TCVN 5574: 2012 CATEGORY
Category................... ............................. .................................................. ............................................... 3 Preface.................. .................................................. .................................................. .................................. 6
1 Scope of application ............................................. .................................................. ........................... 7 2
Normative references .................................................. .................................................. .................................. 7
3
Terminology, units of measure and symbols .................................................. .................................................. ......... 8
3.1 Terms .................................................. .................................................. ............................... 8 3.2 Unit of measure .................................................. .................................................. .............................. ten
3.3 Symbols and parameters .................................................. .................................................. ........ ten 4 General instructions .................................................. .................................................. ................................... 14
4.1 The basic principles ............................................ .................................................. ...................... 14 4.2 The basic requirements calculated on ......................................... ......................................... .......................................... .................................................. ........ .......... 15 4.3 The additional requirements when designing reinforced concrete structures prestressed ................................ ..... 21
4.4 General principles when calculating the flat structure and texture large blocks mention nonlinearity of reinforced concrete ....................... ................................ ................................................ .................. .. ................................. ................................................. .................. .............. 32
5 Materials for concrete structures and reinforced concrete .................................... ..................................... 34 5.1 Concrete ....................... ........................ ............................................ .................................................. ...... ........................................... ................................................ ..... 34 5.1.1 Classification of concrete and use scope ...................................... .................................................. .......... 34 5.1.2 Standard Features and characteristics of concrete calculations ................................... ................................. 38
Frame ................ 5.2 ............................... .................................................. ............................................... 47 5.2.1 Classification of reinforced and the scope of use ...................................... .................................................. ......... 47
5.2.2 Characteristics specific criteria and calculation of reinforced ................................... ................................. 49
6
Calculate concrete structures, reinforced concrete according to the first limit state ............................. 59
6.1 Calculation of concrete structures according to reliability ........................................ .................................................. .................................................. ..... 59
6.1.1 General principles ........................................ ............................................ .... ....................................... .................................................. ........... ................................... ................................... 59 6.1.2 Calculation of concrete structures u nder eccentric compression ............................ ..................................... ......... ............................. ........................................... .................... ...... 60
6.1.3 Profiles bending ........................................... .................................................. .................................... 63 6.2 Calculation of reinforced concrete structures under durability ...................................... ...................................... ....................................... ............................................ ..... sixty four
6.2.1 General principles ............................................ .................................................. .................................................. ................................... sixty four 6.2.2 Calculation under section perpendicular to the longitudinal axis components ................................... ................................... ............................ .................................... ........ sixty four
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TCVN 5574: 2012
A. constructions constructions bending rectangular rectangular section, tee, tee, tee and rings .................... ............................. ........... .. ................. .......................... ......... 66 B. eccentric compressive structures with rectangular section and rings ................................... ............................. 69
C. tensile chord constructions .......................................... .......................................... .................................................. .......................... 77 D. eccentric tensile structures with rectangular section ...................................... .................................................. .. 77
E. Case extensive calculations .......................................... .................................................. .................... 78 6.2.3 Calculation of section inclined to the longitudinal axis components components ..................................... ..................................... ........................................... ............................................. 81
6.2.4 Calculation according according to reliable space section (bending structure twisting simultaneously) ............................. ... .. eighty seven
6.2.5 Calculation of reinforced concrete structures subjected to local loads ................... ............................. ................. ....... 90 A. Calculating local compressive compressive ................. .......................... ................... ................... .............. ..... ............. ...................... .................. ................... ................... ......... ......... 90 B. Calculation of compression perforation .................................................. .................................................. .................. 93
C. Calculation tear .................................................. .................................................. ..................... 95 D. Calculation crease beam .................................................. .................................................. ........... 96 6.2.6 Detailed calculation in place .................................................. .................................................. ....... 97 6.3 Calculation of reinforced concrete structures subject to fatigue .................................................. ......................... 99
7
Calculation of reinforced concrete structures according to limit state Monday ...................... ..................... 101
7.1 Calculate concrete structures under under the formation of cracks ....................................... ........... ........ 101
7.1.1 General principles .................................................. .................................................. ................ 101 7.1.2 Calculator cracks formed perpendicular to the longitudinal axis components .................................................. 101 7.1.3 Calculated according to the cracks formed oblique to the longitudinal axis components .............................................. 105
7.2 Calculation of reinforced concrete structures under the expansion cracks ....................................... ......... 107
7.2.1 General principles .................................................. .................................................. ................ 107 7.2.2 Calculated according to the cracks extend perpendicular to the longitudinal axis components ........................................ 107
7.2.3 Calculated according to the expansion cracks oblique to the longitudinal axis components ........................... ................... ... 110
7.3 Calculation of reinforced concrete structures under the closed cracks ................................. ................................................. ................ 111
7.3.1 General principles .................................................. .................................................. ................ 111 7.3.2 Calculated according to the closed cracks perpendicular to the longitudinal axis components ....................... .................................. ............. ....... 111
7.3.3 Calculated according to the closed cracks oblique to the longitudinal axis components ........................................ ................................................. ......... 112
7.4 Structural calculation of reinforced concrete structures under strain .......................... ................................... .................. ......... 112 7.4.1 General principles .................................................. .................................................. ................ 112
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TCVN 5574: 2012
A. constructions constructions bending rectangular rectangular section, tee, tee, tee and rings .................... ............................. ........... .. ................. .......................... ......... 66 B. eccentric compressive structures with rectangular section and rings ................................... ............................. 69
C. tensile chord constructions .......................................... .......................................... .................................................. .......................... 77 D. eccentric tensile structures with rectangular section ...................................... .................................................. .. 77
E. Case extensive calculations .......................................... .................................................. .................... 78 6.2.3 Calculation of section inclined to the longitudinal axis components components ..................................... ..................................... ........................................... ............................................. 81
6.2.4 Calculation according according to reliable space section (bending structure twisting simultaneously) ............................. ... .. eighty seven
6.2.5 Calculation of reinforced concrete structures subjected to local loads ................... ............................. ................. ....... 90 A. Calculating local compressive compressive ................. .......................... ................... ................... .............. ..... ............. ...................... .................. ................... ................... ......... ......... 90 B. Calculation of compression perforation .................................................. .................................................. .................. 93
C. Calculation tear .................................................. .................................................. ..................... 95 D. Calculation crease beam .................................................. .................................................. ........... 96 6.2.6 Detailed calculation in place .................................................. .................................................. ....... 97 6.3 Calculation of reinforced concrete structures subject to fatigue .................................................. ......................... 99
7
Calculation of reinforced concrete structures according to limit state Monday ...................... ..................... 101
7.1 Calculate concrete structures under under the formation of cracks ....................................... ........... ........ 101
7.1.1 General principles .................................................. .................................................. ................ 101 7.1.2 Calculator cracks formed perpendicular to the longitudinal axis components .................................................. 101 7.1.3 Calculated according to the cracks formed oblique to the longitudinal axis components .............................................. 105
7.2 Calculation of reinforced concrete structures under the expansion cracks ....................................... ......... 107
7.2.1 General principles .................................................. .................................................. ................ 107 7.2.2 Calculated according to the cracks extend perpendicular to the longitudinal axis components ........................................ 107
7.2.3 Calculated according to the expansion cracks oblique to the longitudinal axis components ........................... ................... ... 110
7.3 Calculation of reinforced concrete structures under the closed cracks ................................. ................................................. ................ 111
7.3.1 General principles .................................................. .................................................. ................ 111 7.3.2 Calculated according to the closed cracks perpendicular to the longitudinal axis components ....................... .................................. ............. ....... 111
7.3.3 Calculated according to the closed cracks oblique to the longitudinal axis components ........................................ ................................................. ......... 112
7.4 Structural calculation of reinforced concrete structures under strain .......................... ................................... .................. ......... 112 7.4.1 General principles .................................................. .................................................. ................ 112
4
TCVN 5574: 2012 7.4.2 Determined curvature of reinforced concrete structures on sections no cracks in the tensile .. 112 7.4.3 Determine the curvature of reinforced concrete structures on the cracks in the period under ké o ................................................. .................................................. ........................................... 114 7.4.4 Determine sag .................................................. .................................................. ................. 119 8 The structural requirements .................................................. .................................................. .................................................. ....................... 123
8.1 General requirements .................................................. .................................................. .................... 123
8.2 T he minimum size of the component section .......................... .................................... .................... .............. .... .......................... ............................ .. 123 8.3 Concrete protection layer layer .................................................. .................................................. ....... ...... 124
8.4 T he minimum distance between the bars .................... .............................. .................... .................... .......... .................... ...................... 126 8.5 Reinforced anchor not stretch .................................................. .................................................. .... 126 8.6 Vertical layout for structural reinforcement ...................... ................................. ...................... ................. ...... ............................... .......................................... ............. .. 129 8.7 Horizontal layout for structural reinforcement ...................... ................................. ..................... ................. ....... .............................. ........................................ .......... 131
8.8 Links and details of reinforced welded in place .................................................. ................................ ................................ 134 8.9 Lapping reinforcement not stretch (connection required) .................................................. ............................ 135
8:10 Joints of structural components assembly .................................................. ............................ 137 8:11 Requests own structure .................................................. .................................................. .. 138 8:12 Additional guidance on structure of reinforced concrete structures prestressed ....................... ................................... .............. .. 139 9 The computational requirements and structure of reinforced concrete structure overhaul the houses and buildings ........ 140
9.1 General principles .................................................. .................................................. ............... 140 9.2 Calculation test .................................................. .................................................. ............... 141 9.3 Calculated and constructed structures must be reinforced .............................. ............................................. .................... ..... .................. 143 Annex A (normative) Concrete for concrete structures and reinforced concrete ........ ............... ....... ....... ......... 147
Appendix B ( Refer) ( Refer) Some common types of steel and manuals .......................................... 149 Appendix C (Regulations) (Regulations) deflection and displacement displacement of structures ........................ ................... ....... ........... ................ 155
Annex D (normative) The group's working mode and hoisting crane hanging .................. ................................. ............................. ................ .. 166 Annex E (normative) The quantity used to calculate calculate according to reliability .................................................. .................................................. ......... 167
Appendix F (Regulation) simple beam deflection .................................................. ..................................... 169
Appendix G ( Refer) ( Refer) C onversion table used technical units to SI units .................... ............................. ................. ........ .... 170
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TCVN 5574: 2012
Preface TCVN 5574: 2012 replaces ISO 5574: 1991. TCVN 5574: 2012 is converted from TCXDVN 356: 2005 the National Standards as prescribed in Clause 1 of Article 69 of the Law on Standards and Technical Regulations and b, Clause 2, Article 7 of Decree No. 127/2007 / ND CP dated 1/8/2007 of the Government detailing the implementation of some articles of the Law on standards and technical regulations. ISO 5574: 2012 by the Institute of Science and Technology Building - compiled MOC, the Ministry of Construction proposed, the Directorate for Standards, Metrology and Quality assessment, the Ministry of Science and Technology announced.
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NATIONAL STANDARDS
TCVN 5574: 2012
Structural concrete and reinforced concrete - Design Standards Concrete and reinforced concrete structures - Design standard
1 Scope of Application 1.1
This standard replaces the standard TCXDVN 356: 2005.
1.2
This standard is used to design the concrete structure and reinforced concrete of buildings and structures with different
abilities, working under the effects of temperature system within no more than 50 • C and no lower than minus 70 • C.
1.3
This standard specifies the requirements for design of concrete structures and reinforced concrete made of heavy concrete, lightweight concrete,
concrete granules, concrete honeycomb, hollow concrete as well as concrete self-application productivity.
1.4 The requirements specified in this standard does not apply to concrete structures reinforced concrete and the water works, bridges, traffic tunnels, underground pipelines, road and airport road cars; textured mesh cement, and does not apply to structures made from concrete with medium density less than 500 kg / m 3 a nd greater than 2500 kg / m
3,
C oncrete Polymer concrete binder lime - slag and
binder mixture (except when using the binder in concrete Honeycomb), concrete using adhesive plaster and binder special adhesive, concrete aggregate used special organic, large hollow concrete of the structure.
1.5
When designing structures of concrete and reinforced concrete work in special conditions (affected by the earthquake, the strongest
corrosive environments, in conditions of high humidity, etc ..) must comply with the requirements complement the texture of the standards which correspond
2 Normative references
The following referenced documents are necessary for the application of this standard. For the record referenced documents published in the applicable version yet. For referenced documents do not record the year announced the latest version of the application, including all amendments and supplements (if any). ISO 197: 2002, Metal. Tensile test method.
ISO 1651: 2008, Hot rolled concrete reinforcing steel.
TCVN 1691: 1975, Electric arc weld by hand. TCVN 2737: 1995, Loads and impacts. Design standards. TCVN 3118: 1993, Heavy concrete. Methods for determining compressive strength.
TCVN 3223: 2000, Welding rod for carbon steel and low alloy steel.
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TCVN 5574: 2012
TCVN 3909: 2000, Welding rod for carbon steel and low alloy. Test methods. TCVN 3909: 2000, Welding rod for carbon steel and low alloy. Test methods. TCVN 4612: 1988, System design documentation construction. Reinforced concrete structure. Conventional signs and drawings showing.
TCVN 5572: 1991, System design documentation construction. Structural concrete and reinforced concrete. Construction drawings.
TCVN 5898: 1995, Drawings for construction and civil engineering. Reinforced statistics. TCVN 6084: 1995, Drawings home and construction. Symbols for concrete reinforcement. TCVN 6284: 1997, Reinforced steel prestressed concrete (Part 1-5). TCVN 6288: 1997, Steel wire for cold claw concrete aggregates and produces welded steel mesh reinforcement.
TCVN 9346: 2012, Reinforced concrete structure. Require protection against corrosion in marine environments.
TCVN 9392: 2012, Reinforcing steel in concrete. Arc welding.
3 Terms, units of measure and symbols
3.1 Terminology This standard uses the material characteristics "Range compressive strength of concrete " and "Tensile strength grade of concrete " Substituted respectively for" of concrete under compressive strength " And" of concrete under tensile strength " Used in the standard TCVN 5574: 1991. 3.1.1 Level compressive strength of concrete ( Compressive strength of concrete)
Denoted with the letter B, the average value of the statistics of the compressive strength of the instantaneous, measured in MPa, with probability ensure that no less than 95%, determined on the sample cube standard size (150 mm x 150 mm x 150 mm) manufactured, curing in standard conditions and compression tests at 28 days.
3.1.2 Level tensile strength of concrete ( Tensile strength of concrete) symbol with the letter B t, t he average value of the statistics of tensile strength instant, measured in MPa, with probability ensure that no less than 95%, determined on samples pulled preparation manufactured, curing conditions and standards tensile tests at 28 days.
3.1.3 Bituminous concrete under compressive strength ( C oncrete compressive strength grade classified by)
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TCVN 5574: 2012
Symbol with the letter M, the strength of concrete, obtained a statistical average value of instantaneous compressive strength, measured in newtons per square centimeter DECA (daN / cm 2), d etermined on the cube pattern standard size (150 mm x 150 mm x 150 mm) manufactured, curing in standard conditions and compression tests at 28 days.
3.1.4 Bituminous concrete under tensile strength ( C oncrete tensile strength grade classified by) symbol with the letter K, the intensity of concrete, obtained a statistical average value of the instantaneous tensile strength, measured in newtons per square centimeter DECA (daN / cm 2), determined on samples pulled preparation manufactured, curing conditions and standard tensile tests at 28 days. Correlations between compressive strength levels (drag) of concrete and of concrete under compressive strength (pulling), see Appendix A.
3.1.5 Concrete structures ( Concrete structure)
Structure is made of reinforced concrete is not reinforced or request constructed without regard to the calculation. In the concrete structure of the internal forces calculated by all the impacts are borne by the concrete.
3.1.6 Reinforced concrete structure ( Reinforced concrete structure)
Structure is made of reinforced concrete and reinforced bearing structure. In reinforced concrete structures the internal forces calculated by all the impact sustained by reinforced concrete and bearing.
3.1.7 Reinforced bearing ( Load bearing reinforcement) is set as calculated reinforcement.
3.1.8 Reinforced structure ( Nominal reinforcement) Reinforcement is placed on demand structure without calculation.
3.1.9 Reinforced strain ( Tensioned reinforcement)
Is pre-stressed reinforced in structural fabrication process prior to loading using effects.
3.1.10 Working height of section ( Effective depth of section) Is the distance from the edge compressive structures to focus on vertical cross-section of the tensile reinforcement.
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TCVN 5574: 2012
3.1.11 Protective concrete layer ( Concrete cover)
Concrete layer thickness from the edge components to the nearest surface of the rebar.
01/03/12
Tipping force ( Ultimate Force)
The biggest internal force components, its cross section (with the material characteristics are selected) can withstand.
3.1.13 Limit state ( Limit state) Is a state that, when exceeded dissatisfactory structural requirements for the proposed use it as designed.
3.1.14 Normal usage conditions ( Normal service condition) As conditions of use comply with the requirements before taking the standard or design, satisfying the requirements of technology and use. 3.2 Units of measurement
In this standard using the SI unit of measurement. Unit length: m; unit stress: MPa; force units: N (unit conversion table see Appendix G). 3.3 Symbols and parameters
3.3.1 The geometrical characteristics
width rectangular section; width rib section and the letter T I;
b
b f
ten
b •f
width wing section and the letter T I corresponding tensile and compression in the region;
hour
the height of the rectangular section, and the letter T I;
hour f , hour f •
portion of the wing section height and the letter T I respectively located in the tensile and compression;
a, a •
distance from synergies in the corresponding reinforcement S a nd S • t o the nearest boundary of the section;
hour , 0hour • 0
working height of the section, respectively by h-а a nd h-a ';
x
height concrete compressive zone;
•
the relative height of the concrete under compression, by
S
distance belt length reinforced structures;
hx0 ;
TCVN 5574: 2012
e 0
the eccentricity of axial force N for the focus of the conversion section, determined in accordance with guidelines specified in 4.2.12;
e 0m
the eccentricity of front downforce P f or emphasis conversion section, determined in accordance with guidelines specified in 4.3.6; the eccentricity of synergy between axial force N a nd compressive forces before P f or emphasis conversion section;
e 0 , tot
respectively respectivelyfrom fromsetpoint setpointdistance distancevertical verticalforce force N t o join forces in reinforced S a nd
e, f •
S •;
e,S e sp
respectively around respectively from setpoint axial force N a nd compressive forces before P
to focus reinforced section S;
l
rate structures;
l 0
calculate the length of structures subjected to longitudinal compressive forces; value 0
l
taken under
£ 31, £ 32 and 6.2.2.16;
i
radius of inertia of a cross section of the components of the focus section;
d
nominal diameter of the rebar;
A S A
's
respectively sectional area of reinforcement does not stretch S a nd reinforced stretch '
S; s till
when determining compressive strength before P - respectively the area of the section does not stretch reinforced section S a nd '
S; A sp A A sw
'sp
respectively cross-sectional area of the tensile reinforcement S and S •; sectional area of the reinforcement belt placed in the plane perpendicular to the longitudinal axis and crossing structures inclined section;
A
sectional area of reinforcing bars placed in the inclined plane oblique angle to the longitudinal axis and crossing
s , inc
structures inclined section; Reinforced content defined as the ratio between the cross section area of reinforcement S a nd a cross section area of
•
structures
bh,0r egardless of compressive and pulling wings;
A
the entire area of a cross section of concrete;
A b
sectional area of the concrete under compression;
A bt
sectional area of concrete in tension zones;
A red
sectional area of structural conversion, determined as directed in 4.3.6;
A loc first
Concrete Compressive area locally;
S b ••0
S b s tatic torque of the corresponding cross-sectional area of the concrete compressive and bear 0 pull to neutral axis;
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TCVN 5574: 2012
S S •0s tatic torque of the area corresponding reinforced section S and S • f or neutral axis;
S,S 0 I
moment of inertia of the concrete section of the focus of the structural section;
I red
moment of inertia of the section converted to its focus, determined as directed in 4.3.6;
I S
moment of inertia of the section reinforced with the focus of the structural section;
I b 0
moment of inertia of the cross section for concrete compressive neutral axis;
I
S 0
, I •S m 0 oment of inertia of the respective reinforced section S a nd S • f or neutral axis;
W red
the bending resistance torque conversion section of components for fiber tension at the border, defined as for elastic materials as directed in 4.3.6.
3.3.2 Characteristics reinforced positions in a cross section of structures S
Reinforced vertical symbols:
•
when exist both cross-sectional area of concrete tensile and compressive forces due to the effect of exchange: S denotes reinforcement in the tensile set;
S •
•
when the entire concrete compressive zone: S denotes reinforced compressible boundary set at less;
•
when the entire area of concrete in tension:
+
for tensile structures eccentricity: denotes reinforced tensile set at more marginal;
+
for tensile structures centered: indicates reinforced on the entire cross section of the structures;
Reinforced vertical symbols:
•
when exist both cross-sectional area of concrete tensile and compressive forces due to the effect of exchange: S • denotes reinforced in the area put under compression;
•
when the entire concrete compressive zone: indicates reinforced compressible boundary set at more;
•
when the entire area of concrete in tension for tensile structures eccentricity: denotes reinforced tensile set at less margin for tensile structures eccentricity.
Foreign forces and internal forces 3.3.3
twelfth
F
focused external force;
M
bending moment;
M t
torque;
N
vertical force;
Q
power cut.
TCVN 5574: 2012
3.3.4 The featured materials
R,b
R,
ser b
calculate the compressive strength of the concrete shaft with the first limit state and second;
standard compressive strength of the concrete shaft with the first limit state (intensity prismatic);
R bn
R,bt
R,
bt ser
calculated tensile strength of concrete shaft with the first limit state and second;
R btn
Standard tensile strength of concrete shaft with the first limit state;
R bp
the intensity of the start resistant concrete pre-stressed;
R,S
R s , ser
tensile strength of the reinforcement calculated with the first limit state and second;
tensile strength of reinforced horizontal calculation determined by the requirements of
R sw
5.2.2.4; R sc
compressive strength of reinforced calculated with the first limit state;
E b
initial elastic modulus of concrete compression and drag;
E S
modulus of reinforcement.
3.3.5 Characteristics of prestressed structures
P
compressive forces before, determined by the formula (8), taking losses stresses in reinforcement for each phase of construction work;
•
sp
, • •sp
respectively prestressed reinforced in S a nd S • b efore compression reinforced concrete when the strain on the pad (stretch before) or at the time of prestressing value in concrete is reduced to zero by acting on the structural external forces or external forces actual convention. Actual external force or conventions shall be determined in accordance with the requirements stated in 4.3.1 and 4.3.6, which include loss reinforced the stress in phase with each work of structures;
•
bp
compressive stress in concrete in front compression process, determine at the request of
4.3.6 and 4.3.7 may include loss reinforced the stress in phase with each work of structures;
• sp
coefficient precision tensile reinforcement, determined as required in 4.3.5.
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TCVN 5574: 2012
4 General Instructions
4.1 The basic principles 4.1.1 The concrete structure and reinforced concrete should be calculated and composition, choice of material and size of the structure so that it does not appear the limit state reliability as required. 4.1.2 The selection of structural solutions need to come from rationality in economic terms - Technical applying them in the construction conditions in detail, taking into account the maximum reduction of materials, energy, labor and construction costs by:
•
Use the materials and structures effectively;
•
Reducing structural weight;
•
Maximum use of physical and mechanical characteristics of the material;
•
Use of materials on site.
4.1.3 When designing buildings and structures, to create structural diagrams, select size section and arranged reinforcement ensures reliability, stability and the unchanging spatial consideration in the overall as well as individual sets of structural components in the construction phase and use.
4.1.4 Assembled structures to suit the conditions produced by the motor in the specialized factory.
When selecting components for structural assembly, need to prioritize the use of str uctural prestressed made from concrete and reinforced high-intensity, as well as structures made from lightweight concrete and concrete honeycomb absence require limited by the standards relating respectively. Need selection, combination of reinforced concrete components assembled to a reasonable level which production conditions and transport and erection allow.
4.1.5 For in-situ structural, Notes unified sizes to be able to use formwork rotated several times, as well as using the space frame has been reinforced modular production.
4.1.6 For structural assembly, need special attention to reliability and longevity of joints. Need application of technology solutions and structures that structural joints transmission certainty and ensure the durability of the components in the connector and ensure the cohesiveness of the new concrete poured with concrete old texture.
4.1.7 Concrete components are used: a)
Most of the compression-bearing structure with the eccentricity of axial force does not exceed the limit specified in 6.1.2.2.
b)
In some structural compressive deviation great interest as well as in structural bending when the destruction they do not pose a
direct danger to people and the integrity of the device (the details are based on continuity etc ..).
NOTE: texture is considered concrete structures if their durability during use only by the individual concrete guarantees.
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TCVN 5574: 2012
4.2 The basic requirements for compute 4.2.1 Reinforced concrete structures should satisfy the requirements calculated in accordance with reliability (the first limit state) and satisfy the normal conditions of use (the second limit state). a)
Calculated according to the first limit state to ensure the structure:
•
Not brittle fracture, plastic, or other destructive form (in case of necessity, calculated in accordance with reliability regardless of the
deflection of the structure at a time before being destroyed);
•
Do not lose stability in shape (calculated stable structures thin) or location (calculated against flip and slide the retaining wall,
calculated against uplift for the reservoir submerged or underground, pumping stations, etc ..);
•
Not ruined because of fatigue (calculated fatigue for structures or structures subjected to load repeat the type of mobile or
pulse: eg crane beams, foundation frames, floors have put some machinery unbalanced);
•
Not undermined by the simultaneous effect of human factors and the adverse effects of environmental (impact of recurring or
frequent aggressive environments or fire). b)
Calculated according to the second limit state to ensure the normal working of the structure so that:
•
Not for the formation and expansion cracks or fissures excessive long-term use if conditions do not allow forming or expanding
cracks in the long term. •
No distortions exceed permissible limits (deflections, rotations, slip angle, oscillation).
4.2.2 Calculate the overall structure as well as the calculation of its individual components should be conducted for all stages: manufacturing, transportation, construction, use and repair. Diagram computed for each phase must be compatible with the selected structural solutions.
Allow no need to calculate check the expansion cracks and distortion if the experimentally or actually used the similar structure was confirmed: the width of cracks at every stage does not exceed the allowable value and structure with the stiffness in the use phase.
4.2.3 When calculating the structure, value load and impact, coefficient of reliability of load, factor combinations, coefficient reduction as well as the classification load regular and temporary need to get with the standards current load and impact.
Loads are included in the calculation according to the second limit state need to take follow instructions 4.2.7 and 4.2.11. NOTE 1 in climates too hot which is not protected structures subjected solar radiation, it is necessary to mention the effects of climate heat.
NOTE 2: For structures exposed to water (or in water) need to mention the backwash water pressure (load from the standard design hydraulic structures).
NOTE 3: The concrete structure and reinforced concrete should also be guaranteed fire resistance required by the current standards.
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TCVN 5574: 2012
4.2.4 When calculating the structural components of the assembly may include additional internal forces generated during transport and installation cranes, loads due to self-weight structures need multiplied by the motivation, degree
1.6 when shipped and 1.4 degrees when mounted crane. For the above motivational factor, if any firm basis to allow taking the lower value but not less than 1.25. 4.2.5 The textured semi assembled as well as structural monolithic column bearing loads of construction should be calculated according to reliability, according to the formation and expansion of cracks and under strain in two stages to work following :
a)
Freshly poured concrete before reaching prescribed intensity, structural loads are calculated by weight of the freshly poured
concrete and of any other loading effects during concreting. b)
Freshly poured concrete after reaching specified intensity, structural loads are calculated in effect during construction and
payload when used. 4.2.6 Internal forces in reinforced concrete structures of redundancy due to the effect of load and displacement forced (due to changes in temperature, humidity of concrete, shifting the pillows, etc ..), as well as internal forces in isostatic structures when calculating the deformation in the diagram, is determined taking into account the plastic deformation of concrete, reinforced and having regard to the presence of cracks.
For structures that method of calculating the internal forces have to mention the plastic deformation of reinforced concrete is not yet complete, as well as in the calculation phase intermediate to structural redundancy may include plastic deformation, allowing internal forces determined in accordance with material working hypothesis of linear elastic.
4.2.7 Crack resistance of the structure or structural parts are classified into three levels depending on their working conditions and the type of reinforcement used. Level 1: Do not allow cracks to appear;
Level 2: Allows the short-term expansion of cracks with width restrictions
a crc first but guaranteed after
cracks which will inevitably be closed again; Level 3: Allows the short-term expansion of the crack but the width restriction LT width of cracks but with width restrictions
a crc 2
a crc first and the open
.
Short-term crack width is understood that the expansion cracks when subjected to structural load and frequent, temporary load short and long term. Long-term crack width be construed as extending only structural cracks when subjected to regular load and long-term temporary load.
Level crack resistance of structural reinforced concrete as well as value width allowed limit of cracks in the environmental conditions are not aggressive given in Table 1 (ensure limited permeability for texture) and Table 2 ( safety protection for reinforcement).
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TCVN 5574: 2012
Table 1 - Superior crack resistance and crack width values limited to ensure limited permeability for t he structure
Working conditions of structural
Level anti-cracking and crack width value limit, mm to ensure the structural limit infiltration
when the entire
1. Structure of liquid under
section tensile
pressure or slightly
when a compressive
Level 1*
a crc = 0first.3 a crc = 02.2
Level 3
part section
a crc = 0first.3
2. Structural pressure of bulk materials
Level 3
a crc = 02.2 * Priority use pre-stressed structures. Only when there is a new facility allowing users certainly not pre-stressed structures with required anti-crack level is Level 3.
Load used in calculations using reinforced concrete structures under the conditions established, expanded or closed cracks obtained in Table 3. If the structures or parts of them may require anti-cracks are level 2 and 3 but under the effect of loads corresponding to Table 3 cracks are not formed, there is no need to calculate conditional expansion marks short-term and closed cracked cracks (for level 2), or under conditions of expansion cracks short- and long-term (for level 3).
The anti-cracking level requirements for reinforced concrete structures above apply to cracks and fissures perpendicular to the longitudinal axis is tilted structures.
To avoid cracks extending along the required structural measures (eg reinforced horizontal). For prestressed structures, in addition to the above measures still need to be limited in the concrete compressive stress in the compression stage before the concrete (see 4.3.7).
4.2.8 At the ends of prestressed structures reinforced with no anchor, not allowing cracks to appear in the TV segment stresses (see 5.2.2.5) when the load components often temporary, permanent and temporary short-term time coefficient f
•
1.0 degree.
In this case, the prestressing reinforcement in transmission segment is considered as stress increases linearly from the value 0 to the largest calculated value. Lets not apply the above requirements for the section lying from the central section converted to border tension (Vertical section) when the effect of pre-stressed, if in the section are not published reinforced stretch position no anchor.
4.2.9 In the case, when subjected to the applied load, as calculated in the compressive structures prestressed appear cracks perpendicular to the longitudinal axis structures in various stages of production, transportation and installation up, they need to consider the decline of the crack resistance as well as the increasing tension sag during use.
For components are calculated under the effect of the load loop, not allowing cracks to appear above.
17
TCVN 5574: 2012
For reinforced concrete structures reinforced at which their bearing capacity lost simultaneously with the formation of cracks in the concrete in tension (see 7.1.2.8), the reinforced cross-sectional area along tension should increase to at least 15% of the area of reinforcement required when calculated according to reliability.
a crc first and
Table 2 - Superior crack resistance of reinforced concrete structures and values crack width limit a crc 2
, to protect the safety of reinforced
Crack resistance levels and values
a crc first and a crc 2
mm Steel bar group CI, AI, CII, A-II, CIII, A-III, Working conditions of
Steel bar group AV, A-VI
Steel bar group AT-VII
A-IIIB, CIV A-IV
structure
Steel fiber group
BI and Bp-I
Steel fiber B-II group and Bp-II, K-7, K-19 has a
and K-7 small diameter not
diameter of not less than
greater than
3.5 mm 1. Onoi covered
Level 3
Steel fiber B-II group and Bp-II
3.0 mm Level 3
Level 3
a crc = 0first.4
a crc = 0first.3
a crc = 0first.2
a crc = 0 2.3
a crc = 02.2
a crc = 0 2.1
2. In outdoor or in the ground,
Level 3
Level 3
Level 2
above or below the water table
a crc = 0first.4
a crc = 0first.2
a crc = 0 2.3
a crc = 02.1
a crc = 0first.2
3. Stay in the ground water table
Level 3
Level 2
Level 2
instead changes a crc = 0first.3 a crc = 0first.2
a crc = 0first.1
a crc = 0 2.2 NOTE 1: Symbol 5.2.1.1 and 5.2.1.9 steel group view. NOTE 2: For steel cable, the provisions in this table are applied to the outer steel fibers. NOTE 3: For structural reinforcement bars using AV group, working in a place covered or outdoor, as has experienced design and use of texture, then allow to increase the value
a crc first and a crc 2 this table.
18
up to 0.1 mm compared with the values in
TCVN 5574: 2012
Table 3 - Load and coefficient of reliability of load
Level crack
Payload and reliability coefficients
•
f
resistance of
•
f
when calculated according to the conditions
expansion cracks
reinforced concrete
cracks formed
Short-term
closed long-term
fracture
-
-
structures
Regular load; Long-term temporary load and first
short-term temporary
-
• f > 1.0 * Regular load; Long-term temporary load and Regular load;
• f > 1.0 * (calculated to
2
regularly; Download
Long-term temporary
short-term temporary
significant
load and short-term
clarify the need to check on the conditions
-
temporary
no expansion cracks and closed our short
weight
Download
• f = 1.0 *
long-term temporary
• f = 1.0 *
term) Regular load; Long-term temporary load and
Regular load;
short-term temporary
Long-term temporary
• f = 1.0 * (calculated to
3
As above
load with
-
clarify the need to check on the conditions
• f = 1.0 *
expansion cracks) * Coefficient is taken as calculated in accordance with reliability. NOTE 1: Load-term temporary and short-term temporary is taken under 4.2.3.
NOTE 2: Loads special mention must be calculated according to the conditions when forming cracks in case the presence of cracks leads to peril (explosions, fires, etc ..).
4.2.10 Deflection and displacement of structures, textures may not exceed the limit allowed for in Annex C. deflection limits of the common components shown in Table 4. 04/02/11 When calculated according to the durability of concrete structures and reinforced concrete subjected to longitudinal compressive forces, need to pay attention to the
e d ue to factors not included in calculations caused.
random eccentricity a
Random eccentricity a
e i n any case be taken not less than:
•
1/600 structural length or distance between the cross section of its associated block displacements;
•
1/30 height of the structures section.
19
TCVN 5574: 2012
Table 4 - The limit deflection of structures common Structures of
Limit deflection
1. Girder crane with: a) quay crane arm
1 / 500L
b) electric crane
1 / 600L
2. There were a flat ceiling, r oof structures and hanging wall panels (when calculating external wall plate plane)
(1/200) L
a) when L <6 m
3 cm
b) to 6 m • L • 7.5 m
(1/250) L
c) when L> 7.5 m
3. Floor to ceiling slopes and stairs (1/200) L
a) when L <5 m
2.5 cm
b) when 5 m • L • 10 m
(1/400) L
c) when L> 10 m
NOTE: L is the span of the beam or statements to 2 pillows; for cantilever L = 2L first L first the length of the coil themselves. NOTE 1: When designing structures before the time camber test calculation minus deflection camber allow it without any special restrictions.
NOTE 2: When subjected to regular load, long-term temporary loads and temporary short-term, the deflection of the beam or in any case should not exceed 1/75 1/150 rhythm or length themselves of the cantilever. NOTE 3: When deflection limits are not bound by the requirements of production technology and formed only by the aesthetic requirements, then to calculate the deflection just took the long-term load is applied. In this case take
• f •
first
Also, for the structural assembly to mention the mutual displacement can occur of structures. The transposition of this depends on the type of structure, method of erection, etc .. For the structural components of redundancy, the eccentricity value 0
e t he vertical force than focus section conversion is taken by the eccentricity is determined from static structural analysis, but not less than
e.a In the structural components isostatic, eccentricity 0
e t aken by total eccentricity is determined
from calculating the static and random eccentricity. The distance between the thermal expansion joints need to be determined by calculation.
For concrete structures and reinforced concrete structures prestressed reinforced anti-crack require Level 3, allowing no need to calculate the distance above if they do not exceed the values in Table 5.
20
TCVN 5574: 2012
Table 5 - The maximum distance between the thermal expansion joints allow no need to calculate Dimensions in meters
Working conditions of the structure in the Structure
Indoor Outdoor
land
40
35
30
structural steel layout
30
25
20
no steel structure layout
20
15
ten
single-storey house
72
60
48
multi-storey building
60
50
40
Frame sold assembled or monolithic
50
40
30
Structural characteristics of monolithic or
40
30
25
Frame assembly Concrete
monolithic
Frame assembly
Reinforced concrete
semi-assembled NOTE 1: This value in the table does not apply to the bearing structure temperature below minus 40 • C. NOTE 2: For the one-story structure, is allowed to increase in value to the table by 20%. NOTE 3: This value given in the table for the frame is the case with no frames or bracing columns when placed in the middle of the block bracing temperatures.
4.3 The additional requirements when designing reinforced concrete structures prestressed
4.3.1 The value of prestressing
•
sp
and sp • •
respectively in reinforced stretch S and S • should be selected
with deviations p t hat satisfies the following conditions:
•
•• sp
•
•• sp
sp
••
sp
••
• R p 0 ''
•• • • p , 3 R ,ser s • • ,ser s
(first)
Inside: p c alculated in MPa, is determined as follows: •
In In case case ase of of of stress st stres ress by by by mechanical mec mecha han nical ical m methods: eth ethods ods: p = 0 .05 sp
•
In the the cas case e of ther therma mall stre stress ss by mea means ns of the therm rmal al and and mec mecha hani nica cal: l:
p • 30 •
•
360
;
(2)
l with l t he tension rebar length (distance between the outer edge of the pedestal), measured in millimeters (mm). In case of tension with automated equipment, worth 360 numerator in the formula (2) is replaced by 90.
21
TCVN 5574: 2012
•
4.3.2 Stress values
children first
Stretch Pedestal taken respectively by
and
sp
•
•
children first
respectively in reinforced stretch S a nd S • c ontrolled after
•
• • and sp
(See 4.3.1) minus the losses due to friction and deformation anchor
of reinforcement (see 4.3.3).
Stress values in tension reinforcement S a nd S • i s controlled in placement when tension reinforcement traction on solid concrete has
• children 2
taken respectively by
• sp
is determined from the stress conditions to ensure
and
and sp • •
• , which which values values • children 2
• children 2
and
•
in cross section calculations. Then
• • children 2
children 2
and
• • children is calculated using the formula: 2
•
•
children 2
•
2
• •
• •
sp
• • • • •
• • • • red baby •
PA p
•
I red
red
PA p
•
•
ye
0m sp
sp
• • •
ye•
0m sp
I red
(3) • • •
(4)
In the formula (3) and (4):
•
sp
• , • sp
P, 0m e
-
determ determine ined d not to ment mention ion loss loss of stre stress; ss;
-
determined determined by by the formula formula (8) (8) and (9), (9), in which which the values values
•
sp
and sp • •
can mention
the first stress loss;
y,sp
- see 4.3.6; Health sp •
• •
EE
bs
.
stresses in structural reinforcement of self-tensioning is calculated from equilibrium conditions with stress (self- inflicted) in concrete.
self-inflicted stress of concrete in the structure is determined from concrete grade according to ability to cause stress
S m p ay include content reinforcement, the distribution of reinforcing steel in concrete (on one axis, two axes, three axes), as well as in the case of necessity to mention the loss of stress due to shrinkage, creep of while concrete load-bearing structures.
NOTE: In the structures made from lightweight concrete with levels from B7,5 to B12,5, values
•
2 children
and
•
•
2 children
are not
exceed the value of 400 MPa, respectively, and 550 MPa.
4.3.3 When calculating the pre-stressed structures, to mention loss of prestressing reinforcement when tension:
•
When the tension on the pad should mention:
+
These cost the first: by deformation anchor, friction reinforced with equipment bending direction, which they stress in reinforcement, due to changes in temperature, due to disfigurement (when tension reinforcement on site), so from quick turn of concrete.
+ •
22
These cost the the second second shrinka shrinkage ge and creep creep of of concrete. concrete.
When the tension on the concrete need to mention:
TCVN 5574: 2012
+
The first loss: anchored by deformation, due to friction with the wall of reinforced steel set (cable) or with the concrete surface of the structure.
+
These cost the second due to slack slack stresses in reinforcement, reinforcement, shrinkage and creep of concrete, compression compression local loops reinforcement on the concrete surface, so deformed joints between concrete blocks ( for structures assembled from blocks).
Loss of reinforcement stress is determined according to Table 6, the total value of the loss is not taken stress less than 100 MPa.
When calculating the self-tensioning structures just mention the stress loss due to shrinkage and creep of concrete depending on concrete grade self-tensioned and humidity of the environment.
For the self-tensioning structural work in water-saturated conditions, not to mention loss shrinkage stress.
Table 6 - stress loss Value loss stress, MPa
Factors causing loss of prestressing reinforcement
when tension on concrete
when tension on pedestal
steel
A. The first loss 1. We stress in reinforcement
•
when stretched by mechanical methods
• • • •
a) for steel fibers
b) for steel bars
•
•
• 0, R
0,
sp
• • 0 •22 ,first • •
, ser s
sp
1 • 20 • sp
-
-
when stretched by thermal or mechanical methods thermoelectric
a) for steel fibers
0, 05
• sp
-
b) for steel bars
0, 03
•
-
here:
•
sp
sp
, MPa, MPa, is is take taken n not not
mention the stress loss. If the calculated loss value was marked "minus" is take the value 0.
23
TCVN 5574: 2012
Table 6 - ( next) Stresses the value loss, MPa
Factors causing loss of prestressing reinforcement
when tension on pedestal
steel 2. The difference in temperature between
For concrete B15 to B40 levels from:
the steel rod heated tension in the region and the receiving device when the tension
when tension on concrete
-
1.25 t •
For concrete B45 levels and bigger:
gets hot concrete
-
1.0 t •
Inside:
• t is the difference between the core temperature
Steel pans are heated and fixed tension (outside the heating) receiving the tension, oC . When the lack of
• t = 65 o C.
accurate data taken
When tension reinforcement in the heating to value enough to offset losses due to stress difference in temperature, the power loss due to the temperature difference of 0 degree.
• ll E
3. Deformation of anchoring devices placed in tension
Inside:
• S
• l the distortion of the washers
Inside:
• 1 • ll2
E l S
• l firstis deformed
forced, forced the local anchorage, taken by 2 mm; when
ECU or buffer between the anchor
there is a slip between the bars in reusable clamp device,
and the concrete, take 1 mm;
• l
verified
according to the formula:
• l = 1.25 + 0.15 d
• l 2 is cup shaped deformation of anchor, anchor screws, taken by 1 mm.
with d the rebar diameter, measured in millimeters (mm);
l i s the reinforcement length stretch (a
l i s reinforced stretch length (distance between the outer edge of the pillow on the base of the mold or equipment), millimeters (mm).
When using thermal stress, loss due to deformation anchor regardless of computation as they are included when determining the total elongation of the reinforcement
24
fiber), or structures, millimeters (mm).
TCVN 5574: 2012
Table 6 ( next) Stresses the value loss, MPa
Factors causing loss of prestressing reinforcement
when tension on concrete
when tension on pedestal
steel 4. Friction of reinforcement
a) with a grooved pipe or concrete
•
surfaces
sp
• •1 • • e •
1 • • • •
• • •
Inside: e is the natural logarithm base;
• , •
coefficient, determined in accordance
with Table 7;
• is the length from the tension device to calculate section, m;
• the total angle of the shaft reinforcement navigation, radians;
•
sp
is taken not to mention the stress
loss. b) with equipment fashioned guide
•
sp
1 • • • 1 • • • • e • •
Inside: e i s the natural logarithm base;
• coefficient, taking 0.25; • the total angle of the shaft reinforcement navigation, radians;
•
sp
taken not to mention the stress loss.
5. Deformation of steel mold when
•
manufacturing reinforced concrete
• ll E
S
structures prestressed
Inside: • c oefficient, obtained by:
+ • •
•
-
, when tension reinforced by size;
21 nn
+ • •
•
, when tension reinforcement method
41 nn
using thermal mechanical winch (50% of capacity due to load heavy objects).
25
TCVN 5574: 2012
Table 6 - ( next) Stresses the value loss, MPa
Factors causing loss of prestressing reinforcement
when tension on concrete
when tension on pedestal
steel
n is the reinforcement group is strained not simultaneously.
• l the displacement of the knee together on the pad under the effect of force P,i s determined from the calculated deformation mold.
l is the distance between the outer edges of the pillow Pedestal stretch. In the absence of data on manufacturing technology and structural mold, mold deformation due to losses taken by 30 MPa.
When using thermal stress, losses due to distortions in the calculation mold regardless because they were included when determining the total elongation of the reinforcement.
6. From quick turn of concrete
a) For natural curing concrete
• 40
bp
• bp
when the
R bp
• •
R bp
• • bp • • 40• 85 • • • • • • R • • bp •
• bp
when the
• •
R bp
Inside • and • c oefficient, taken as follows:
ut not greater than • = 0.25 + 0.025 bp R,b 0.8;
• = 5.25 to 0.185
bp
R,b ut not greater than
2.5 and not less than 1.1;
•
bp
determined at the central vertical reinforcement S and S •• have
included losses under paragraph 1 to 5 of this table.
For lightweight concrete, the intensity at the start caused by 11 MPa prestressed or smaller replacement ratio of 40 to 60.
b) For steam curing concrete
Loss calculated using the formula in Section 6a of this table, then multiply by a factor of 0.85.
26
TCVN 5574: 2012
Table 6 - ( next) Value loss stress, MPa when stretched on
Factors causing loss of prestressing reinforcement
pedestal
when tension on concrete
steel
B. The loss Monday 7. We stress in reinforcement
a) For steel fibers
-
b) For bars
• • • •
•
• 0,
sp
R
-
0,
0 22 •
• • ,first
, ser s
• •
sp
• sp 1 • 20
(See glossary for Section 1
in this table) 8. Shrinkage of concrete (see 4.3.4)
Concrete
Steam curing concrete
curing self
in pressure conditions
concrete
curing of
ozone
course
Heavy
Not dependent conditions
concrete
a) B35 and lower
40
35
30
b) B40
50
40
35
c) B45 and larger
60
50
40
d) Group A
40
Loss is determined according to Section 8a, b in this table and multiplied by the coefficient 1.3
Concrete small
e) Group B
50
Loss is determined according to Section 8a in this table and multiplied by a factor of 1.5
particle
f) Group C
Loss is determined according to Section 8a of the
40
table as for heavy concrete curing self course Lightweight
g) type solid
50
45
40
h) type with voids
70
60
50
aggregate concrete small
9. From the concrete variables (see
4.3.4) a) For heavy concrete and lightweight
150 • •
bp bp R
when the •
•
bp bp R
0, 75
;
aggregate concrete small dense 300 • ••
Inside:
•
bp
bp
R bp •
0, 375
•
when the •
bp
R bp •
0, 75
,
taken as in section 6 of this table;
• coefficient, taken as follows: + concrete with natural curing, take • = first; + with steam curing curing concrete concrete in in atmospheric pressure conditions, taking • = 0 .85.
27
TCVN 5574: 2012
Table 6 - ( finish) Factors causing stress loss in
Stresses the value loss, MPa
reinforcement when tension on concrete
when tension on pedestal
b) Concrete small particle
group A
Losses are calculated according to the formula in Section 9a of this table, then multiply the result by a factor of 1.3
group B
Losses are calculated according to the formula in Section 9a of this table, then multiply the result by a factor of 1.5
group C
Losses are calculated according to the formula in Section 9a of this table when • = 0.85
c) lightweight aggregate concrete small hollow
Losses are calculated according to the formula in Section 9a of this table, then multiply the result by a factor of 1.2
-
10. Local pressed concrete surface
70 to 0.22
ext
d
reinforcement due to torsion or Belt Belt
Inside:
round (when the structure has a smaller
d ext diameter
outside of the structure, cm
diameter of 3 m)
-
11. Deformation by compression joints
lln E •
between blocks (for assembly structures from the block)
S
Inside: n the number of joints between structural and other equipment along the length of reinforced stretch;
• l is deformed pressed at each slot:
+ slot stuffed stuffed with with concrete, concrete, taking taking l
•
= 0.3 mm;
+ with direct coupling slot, taking
• l = 0.5 mm; l i s reinforced stretch length, mm. NOTE 1 loss in reinforcement tensile stress
S • is defined as in the reinforcement S;
NOTE 2: For reinforced concrete structures self-tensioning, shrinkage and loss of concrete creep is determined according to empirical data.
NOTE 3: Symbol of concrete durability level see 5.1.1.
4.3.4 When determining the stress loss due to shrinkage and creep of concrete under section 8 and 9 in Table 6 should be noted:
a)
• ,
Knowing ahead of time loading up the texture, stress loss should be multiplied by the coefficient l
determined by the following formula:
• • l
28
4
(5) • 3100 tt
TCVN 5574: 2012
Inside: t i s the time in days, determined as follows: •
when determining losses due to creep stress: from date concrete compression;
•
when determining loss shrinkage stress: from the concrete end date.
b)
For structural work in conditions of low air humidity than 40%, the stress loss should be increased by 25%. Where structures
made of heavy concrete, concrete granules, working in hot climates and not be protected from solar radiation to calculate the stress losses increased by 50%. c)
If you know the type of cement, concrete components, conditions of manufacture and use of the structure, allows the use of
methods more accurate to determine losses stress when that method is proven to be the basis according to current regulations.
Table 7 - The coefficients for determining losses due to friction stresses reinforcement
The coefficient e To determining l osses due to friction reinforced (see Section 4, Table 6)
Tube groove or surface
contact
•
when reinforcement is
• ribbed bar
steel or steel fiber bundle 1. Type of pipe trench
- with metal surfaces
.0030
0.35
0.40
0.55
0.65
0.55
0.65
0.55
0.65
- Concrete surfaces created by the hard core mold
0
- Concrete surfaces created by soft core mold
.0015 0
2. Concrete Surfaces
4.3.5 Values of prestressing reinforcement included in the calculation must be multiplied by coefficient precision tensile reinforcement sp
•
:
• sp = 1 • • sp •
(6)
In formula (6), the sign "plus" when there is an adverse effect of prestressing (ie during the period specific work of structures or parts under consideration of structures, prestressed reduce bearing capacity to promote the formation of cracks, etc ..); the sign "minus" to have a beneficial effect.
•
In case of prestressing by mechanical methods, value • sp
•
by means of thermal and thermal engines • sp
is determined by the formula: •
• •
sp
•
, 0 •
0.1 degree; when tension
1 5• sp
• •
P
•
1 n
p
• • • •
(7)
but take not less than 0.1; in the formula (7):
29
TCVN 5574: 2012
p, •
sp
see 4.3.1;
n i sp the number of bars in cross section tensile structures. When determining the cost the stresses in reinforcement, as well as under conditions when calculating expansion cracks and distortions calculated by
• • sp equal zero.
taking the value allowed
4.3.6 Stresses in concrete and reinforcement, as well as before the compression force used to calculate concrete structures prestressed concrete is determined according to the following instructions: Stresses in the section perpendicular to the longitudinal axis components are determined according to the principles of calculation of elastic materials. In particular, section calculates the equivalent section i ncludes concrete section can include a decrease due to the tube, slotted and cross-sectional area of longitudinal reinforcement (tension and strain) multiplied by the coefficient • is the ratio between the modulus of elasticity of reinforcementS
E and concrete
b
E. When on the section with concrete
with variety and different reliability levels, it must be converted to a type or a grade based on elastic modulus ratio thereof. Compression pre-tensioning P a nd its eccentricity e 0 c p ompared with the focus of the conversion section is determined according to the formula:
• • • •
0
• • • •
•
• •
•
• • • • AAAAP
sp sp sp ssss
(8)
sp
• A• y A • y• A• y •A e • sss sp sp sp sp sp sp p
• •
•
y
sss
(9)
P
Inside:
•
S
and S • •
respectively reinforced stress in no stretch S a nd S • c aused by shrinkage and
creep of concrete;
y,sp
y, Health sp •• S
respectively, the distance from the Health • S
focus-section converted to points
forces set of internal forces in reinforced stretch S and do not stretch S • ( Figure 1). • ' S A ' S
• ' sp A ' sp S S ' y
p
s ' y
®eng ®i too white t © m
S
h t l a e H
p s
tiOt Dion provided a cyclic
h t l a e H
m 0
e P • sp A sp
• S A S
Figure 1 - Diagram of the reinforced front downforce on section of horizontal reinforced concrete structures
In the case of reinforced curved stretch, values
•
sp
and sp • •
should multiply
with • and • • r espectively of the shaft angle to the longitudinal axis of reinforced structures (at the section under consideration).
30
cosa nd •
cos
• • ,
TCVN 5574: 2012
•
Stresses
sp
and sp • •
be obtained as follows:
a)
In the period before the concrete compression: there is mention of the first loss.
b)
In the use of: have to mention the first loss and second Value stresses
•
S
and S • •
taken as follows:
c)
In the period before the concrete compression: taken by losses due to stresses from rapid variations under 6 Table 6.
d)
During the period of use: take the sum of the losses due to shrinkage stress and creep of concrete under section 6, 8 and 9 of
Table 6. 4.3.7 Compressive stress in concrete bp
•
bp R bp
stresses
•
stage compression before concrete must satisfy the condition: ratio
shall not exceed the values given in Table 8.
•
defined at the outermost fibers of compressible concrete mention the loss under 1 to 6
bp
• sp •
Table 6 and the coefficient of precision tensile reinforcement
first .
•
Table 8 - The ratio of compressive stress in concrete bp
the strength of concrete
stage compression before and
R t he start of pre-stressed bear (
bp
• Score
Stress state
•
bp R bp
bp R bp
not greater than
Tensile reinforcement
of section
method
compression
when compressed axially
1. Stress is reduced or unchanged when the
)
eccentric
Pedestal (front stretch)
0.85
0.95 *
On concrete (strained back)
0.70
0.85
Pedestal (front stretch)
0.65
0.70
On concrete (strained back)
0.60
0.65
structures subjected to external forces
2. Stress-bearing structures was increased when the effects of external forces
* Apply to components manufactured under conditions gradually increasing compression force, when the details link steel reinforcement in knee and indirectly with steel content by volume
•
v
l p (See 5.2.2.5), lets get value
period of not less than the length of the transmitted stress •
bp
• 0.5% (see 8.5.3) on
,0 . R bp • first
NOTE: For lightweight concrete from B7,5 to B12,5 level, value
•
bp
R bp
no greater than 0.3 should get.
4.3.8 For structural prestressed which has foreseen to adjust the compressive stress in the concrete during use (eg in reactors, tanks, TV tower), to use reinforced no adhesion tension, there should be measures to protect effectively reinforcing steel from corrosion. For structural adhesive Prestressed not be calculated according to the requirements crack resistance level 1.
thirty first
TCVN 5574: 2012
4.4 General principles when calculating the flat structure and texture large blocks mention nonlinearity of reinforced concrete
4.4.1 The calculation of the structural system of concrete and reinforced concrete (structural linear, structural flat, the fabric of space and massive structures) for the limit state the first and second follow application productivity, internal force, deformation and displacement. Factors stress, internal forces, deformation and displacement which is calculated from the impact of external forces on the structure above (forming the structural system of buildings and structures) and should include nonlinearity physics, anisotropy and in some cases necessary to mention the word processing and the accumulation of damage (a lengthy process) and nonlinear geometry (mostly in the texture of the thin) .
NOTE: anisotropy is not identical in nature (in this case the mechanical properties) according to different directions. Intuitive user is a form of anisotropy, which is not identical in nature is under the direction of three planes of symmetry perpendicular to each other in pairs.
4.4.2 Need to mention the physical nonlinearity, anisotropy and creep properties of the correlation determined in relation to the stress deformation, as well as in terms of durability and crack resistance materials. When that need is divided into two stages of deformation structures: before and after the formation of cracks.
4.4.3 Before the formation of cracks, must use nonlinear model directly oriented towards concrete. This model allows developers to mention the effects of the expansion direction and the heterogeneity of the deformation of compression and shearing. Model allows use of concrete nearly isotropic. This model allows to mention the appearance of the above elements in three dimensions. For reinforced concrete, calculated at this stage need to come from deformation and longitudinal axis of the reinforcing steel and concrete that surrounds it, except for paragraph ends reinforced not arranged anchor dedicated . When the risk of aneurysm reinforcement, should limit compressive stress value limit.
NOTE: The expansion is the increase in the volume of an object of compression due to the development of micro-cracks stains and cracks have great length.
4.4.4 Under conditions of durability of concrete, should include a combination of stress under different directions, because the compressive strength of the two-axis and three-axis greater than the compressive strength of a shaft , even when under compression and pulling at the same time intensity which can be smaller than when only concrete compressive or pulling. In case of necessity, it should be noted long-term effects of stress.
Conditions of reinforced concrete strength no cracks should be established on the basis of the conditions of the material strength components reinforced concrete viewing environment as two components. 4.4.5 Get the strength of the concrete conditions in the environment as a condition of two components forming cracks.
4.4.6 After appearing cracks, need to use object model anisotropic general form in relations between internal forces nonlinear stress or displacement with taking into account the following factors: •
Angle of comparison with reinforced cracks and fissures diagram;
•
The expansion of the cracks and sliding edge cracks;
•
Stiffness of reinforcement:
+
32
Longitudinal axis: there is mention of reinforced adhesive strip or piece of concrete between the cracks;
TCVN 5574: 2012
+
Tangentially with marginal cracks: there is mention of concrete softness at the edge cracks and axial stress and tangential stress corresponding reinforcement in cracks.
•
The hardness of the concrete:
+
Between the cracks: there is mention of the power vertical and concrete slip between the cracks (in the diagram cracks intersect, this stiffness is reduced);
+ •
In the cracks: there is mention of the power vertical sliding edge cracks in concrete.
The gradual loss of partial simultaneity of axial deformation of the reinforcement and concrete between the cracks.
In the model the deformation of reinforced structures with cracks not only mention the hardness of the concrete in between the cracks.
In these cases the appearance of cracks oblique, should mention the specific characteristics of deformation in the upper concrete cracks. 4.4.7 Width cracks and shifting relative sliding of the boundary cracks to determine on the basis of moving in different directions of the bars than the margin of cracks cut through them, taking into consideration the distance between the cracks and shifting conditions simultaneously. 4.4.8 Conditions reliability of structures and structural-panel Massive cracks to determine based on the following assumptions:
•
Vandalism occurs by reinforcement elongation significantly in the cracks most dangerous, often lying compared with rebar and
break concrete of a strip or block between the cracks or external cracks (for example in the areas of compressive lying on cracks);
•
Compressive strength of concrete decreased by tensile stresses caused by the adhesive force between the reinforced concrete and
tensile perpendicular, as well as by the horizontal shift of the crack near the edges reinforced;
•
When determining the strength of the concrete should consider forming cracks diagrams and inclination of cracks compared to reinforced;
•
Need to mention the stresses of rebar reinforced axially oriented. Lets mention tangential stress in reinforcement at the position
of cracks (effect nagen), that the bars do not change direction;
•
Cracks in vandalism, the bars cut through it attained calculated tensile strength (for reinforcement without the stress flow limit
should be controlled in the process of calculating the deformation).
Concrete strength in different regions will be assessed according to the stresses in the concrete as a component of the environment are two components (not to mention the stress converted in the reinforcement between the cracks identified mention the stress in the cracks, adhesion and the gradual loss of partial simultaneity of the axial deformation of the reinforced concrete).
33
TCVN 5574: 2012
4.4.9 For reinforced concrete structures can withstand the small plastic deformation, allowing determine their bearing capacity using limit equilibrium methods. 4.4.10 When structural calculations according to durability, deformation, the formation and expansion cracks finite element method, to examine the conditions durability, crack resistance of all the elements of the structure, as well as check conditions appear excessive deformation of the structure. When assessing the limit state according to reliability, allowing some elements sabotaged, if that does not lead to the destruction subsequent structural and after the load is considered severance effects, texture still normal use or can be restored.
5 Materials for concrete structures and reinforced concrete 5.1 Concrete 5.1.1 Classification of concrete and scope of use
5.1.1.1 This standard allows the use of the concrete follows: •
Heavy concrete with average bulk density of 2200 kg / m m 3 t o 2500 kg / m
•
Concrete small particle has a volume greater than the average 1800 kg / m 3;
•
Lightweight structural concrete solid and void;
•
Autoclaved honeycomb concrete and autoclaved;
•
Special concrete: Concrete stress itself.
3;
5.1.1.2 Depending on the performance and working conditions, the structural design of concrete and reinforced concrete need to specify the quality criteria of concrete. The basic criteria are:
a)
Compressive strength grade B;
b)
Level axial tensile strength B t ( s pecified in this specific case there is decisive and tested during production);
c) follow-resistant Marx, denoted with the letter W (specify for required structural limitations permeability);
d) Mark under the average density D (indicated for the structural requirements of insulation); e) ability to cause Marx under stress
S p ( d esignated for structural stress itself, as characterized
This is included in the calculation and should be checked during the manufacturing process). NOTE 1: Level compressive strength and tensile axial, MPa, must correspond with the intensity values ensure 95% probability. NOTE 2: Bituminous concrete under stress itself causes stress self worth in prestressed concrete, MPa, caused by self-expansion concrete, along with levels of steel in concrete is
•
0.01.
NOTE 3: To facilitate the use in practice, in addition to specifying concrete grade can put concrete grade in parentheses. Example B30 (M400).
34
•
TCVN 5574: 2012
5.1.1.3 For concrete structures and reinforced concrete, prescribed use of concrete and grade level according to Table 9:
Table 9 - Conditions of Use and concrete grade level
Classifications
By level of
Concrete
Level or grade B3,5; B5; B7,5; B10; B12,5; B15; B20;
Heavy concrete
B25; B30; B35; B40; B45; B50; B55; B60
compressive strength
Self-stress concrete
B20; B25; B30; B35; B40; B45; B50; B55; B60
Concrete small particle group A: curing natural or
B3,5; B5; B7,5; B10; B12,5; B15; B20;
is curing in atmospheric pressure conditions, B25; B30; B35; B40 aggregates with larger modules 2.0 magnitude Group B: hardener or curing naturally in
B3,5; B5; B7,5; B10; B12,5; B15;
atmospheric pressure conditions, aggregates B20; B25; B30; B35 with module higher or lower 2.0
Group C: be autoclaved
B15; B20; B25; B30; B35; B40; B45; B50; B55; B60
Lightweight aggregate D800, D900
B2,5; B3,5; B5; B7,5;
concrete with marking according to the
D1000, D1100
B2,5; B3,5; B5; B7,5; B10; B12,5
D1200, D1300
B2,5; B3,5; B5; B7,5; B10; B12,5;
average density
B15 D1400, D1500
B3,5; B5; B7,5; B10; B12,5; B15; B20; B25; B30
D1600, D1700
B5; B7,5; B10; B12,5; B15; B20; B25; B30; B35
D1800, D1900
B10; B12,5; B15; B20; B25; B30; B35; B40
D2000
B20; B25; B30; B35; B40
35
TCVN 5574: 2012
Table 9 - ( finish)
Classifications
Concrete
By level of
Concrete honeycomb
compressive strength
marks according to the average density
Level or grade autoclaved
not autoclaved
D500
B1; B1,5;
D600
B1; B1,5; B2
B1,5; B2; B2, 5
D700
B1,5; B2; B2,5; B3,5
B1,5; B2; B2,5
D800
B2,5; B3,5; B5
B2; B2,5; B3,5
Level axial tensile
D900
B3,5; B5; B7,5
B3,5; B5
D1000
B5; B7,5; B10
B5; B7,5
D1100
B7,5; B10; B12,5; B15 B7,5; B10
D1200
B10; B12,5; B15 B10; B12,5
Hollow concrete
D800, D900, D1000
B2,5; B3,5; B5
block with grade
D1100, D1200, D1300
B7,5
average volume:
D1400
B3,5; B5; B7,5
Heavy concrete, concrete self-stress, small particles of concrete, lightweight concrete
B t 0 .8; B t 1 .2; B t 1 .6; B t 2; B t 2 .4; B t 2 .8; B t 3.2
strength
Water tightness Heavy concrete, concrete granules, lightweight concrete
W2; W4; W6; W8; W10; W12
Mark according to
D800; D900; D1000; D1100; D1200;
Lightweight concrete
the average
D1300; D1400; D1500; D1600; D1700;
density
D1800; D1900; D2000
Concrete honeycomb
D500; D600; D700; D800; D900; D1000; D1100; D1200
Hollow concrete
D800; D900; D1000; D1100; D1200; D1300; D1400
Concrete grade according to ability
Self-stress concrete
S p 0 .6; S p 0.8; S p first; S p 1 .2; S p 1.5; S p 2; S p 3; S p 4.
self-inflicted stress NOTE 1 In this standard, the term "light concrete" and "hollow concrete" refers to symbols corresponding to light concrete structure solid and lightweight concrete with porous structure (the rate percentage of voids greater than 6%). NOTE 2: concrete granules Group A, B, C should be specified in the design drawings.
36
TCVN 5574: 2012
5.1.1.4 Age of concrete to determine the level of compressive strength and tensile axial specified in the design is based on the actual time from the moment construction texture until it starts to load the design, in the construction methods, in terms of concrete curing. When lack of numbers, taking the age of the concrete is 28 days.
5.1.1.5 For reinforced concrete structures, does not allow: •
Using heavy concrete and concrete grade granules smaller compressive strength B7,5;
•
Using lightweight concrete with compressive strength level for smaller B3,5 and B2,5 textured layer for two-layer structure.
Use concrete with compressive strength levels satisfy the following conditions:
•
For reinforced concrete structures made from concrete and lightweight concrete weighs the computation load repeat: not less than B15;
•
For reinforced concrete structures under compression rods made from heavy concrete, concrete and lightweight concrete granules: not less
than B15;
•
For reinforced concrete structures compressible high load bars (eg crane load column, the column of the multi-storey
downstairs): not less than B25. 5.1.1.6 For structures self tensioning made of heavy concrete, concrete granules, lightweight concrete, have arranged reinforcement tension, stiffness of concrete depending on the type and group of reinforced st retch, diameter reinforced stretch and the anchor device, take not less than the values given in Table 10.
Table 10 - Terms of use of concrete durability level for pre-stressed structures Range of concrete durability Sort and group tension reinforcement
not less than
1. Steel fiber groups: B-II
B20
(with anchor)
Bp-II (no anchor) diameter:
Less than or equal 5 mm
Greater or equal to 6 mm
B20
B30
B30
K-7 and K-19
2. Steel bar with no anchor, roads closed hour: + from 10 mm to 18 mm, group
+ 20 mm or greater, group
CIV, A-IV
B15
AV
B20
A-VI-VII and Ат
B30
CIV, A-IV
B20
AV
B25
A-VI-VII and Ат
B30
37
TCVN 5574: 2012
R ( c ontrolled as for compressive strength level) just
Concrete strength at the time of compression before bp
not less than 11 MPa for, even when using steel bar A-VI group, A T- V I, A T- V IK and A T- V II, steel fibers have high strength anchors and steel cables do not need to specify it is not less than 15.5 MPa. Besides,
R bp
not less than 50% level of the compressive strength of concrete.
For texture calculated load loop, using reinforced fiber pre-stressed and reinforced bars pre-stressed group CIV, A-IV with all diameters, as well as groups of AV diameters from 10 mm to 18 mm, the value of the minimum level concrete in Table 10 must be increased to a level (5 MPa) corresponding to the intensity of the start resistant concrete pre-stressed.
When designing the form of its own, allowing the degradation of concrete minimum to a level of 5 MPa compared with the values given in Table 10, simultaneously with the reduction of the intensity of the concrete at the start under prestressed .
NOTE 1: When calculating structural reinforced concrete stage compression before, characterized calculation of concrete is taken as to grant the durability of concrete, there is value in the strength of concrete at the start be tensioned (by linear interpolation). NOTE 2: Where the design of structures covering a special layer that functions as insulation, while the relative value of the compression pre-tensioning
•
bp
R bp
no greater than 0.3 allows the use of reinforced stretch CIV group, A-IV has a diameter no greater than 14
R should appoint not less than 80% level of concrete durability.
mm with lightweight concrete from B7,5 to B12,5 level, while bp
5.1.1.7 When no bases empirical own, does not allow the use of concrete granules for structural reinforced concrete load loop, as well as for structures of reinforced concrete prestressed span greater than 12 m steel fiber used B-II, Bp-II, K-7, K-19.
When using concrete structures granules, against corrosion and ensure the cohesion of concrete with reinforcement tension in the groove and on the concrete surface of the structure, level of compressive strength of concrete is specified not less than B12,5; even when the tube is used to pump concrete to use not less than B25 levels.
5.1.1.8 To insert the joint structures of reinforced concrete structures assembled, concrete grade is assigned depending on the working conditions of the structures, but took no less than B7,5 for joints without reinforcement and take not less than B15 with reinforced joints.
5.1.2 Characteristics specific criteria and calculation of concrete 5.1.2.1 The intensity kind of concrete standards include axial compression intensity prismatic form (intensity prismatic) bn
R a nd the intensity of the pull shaft
btn
R.
The strength of the concrete calculation when calculated according to the first limit state the second limit state
R,
, R,
ser b
bt ser
the coefficient of reliability of corresponding concrete compression bc
• bt of some major concrete in Table 11.
38
R,b
R a nd follow bt
is determined by taking the standard intensity divided
•
and when pulled bt •
. The values of coefficients bc
•
and
TCVN 5574: 2012
Table 11 - Coefficient of reliability of some kind of concrete
• bc and when pulled bt • when compressed
• bc
Value
and bt •
While structural calculations
according to limit state
first Concrete
• bt to the level of concrete
Monday
• bc , • bt
durability
• bc
compressible
tensile
Heavy concrete, concrete granules, self-stressing concrete,
1.3
1.5
1.3
1.0
1.5
2.3
-
1.0
lightweight concrete and hollow concrete
Concrete honeycomb
R ( c ompressive strength of concrete standards
5.1.2.2 Intensity of concrete standards when compressed axially bn
cardboard), depending on the level of the compressive strength of concrete for in Table 12 (rounded). Intensity of
R
concrete standards when pulled axially btn
(Tensile strength of concrete standards)
in cases where the tensile strength of concrete is not controlled in the production process is determined depending on the level of the compressive strength of concrete shown in Table 12.
Intensity of concrete standards when pulled axially btn
R
(Tensile strength of concrete standards)
in cases where the tensile strength of concrete is controlled in the manufacturing process is removed by tensile strength level with probability guaranteed. 5.1.2.3 The calculated intensity of concrete b
R,
R,bt
R,
, R,
ser b
bt ser
(Rounded) depending on the level
and the compressive strength of concrete axial pull for in Table 13 and Table 14, when calculated according to the first limit state and Table 12, when calculated according to the status of second limit.
The strength of the concrete calculation when calculated according to the first limit state reduced (or increased) by multiplying with the coefficient of working conditions of concrete bi
R ab nd
bt
•
R OK . the system
This mention of the specific characteristics of the concrete, the impact of long-term, repetitive load, conditions and working stage of the structure, method of manufacture, size section, etc .. coefficient values working conditions bi
•
given in Table 15.
39
4 0
Table 12 - The strength of concrete standards bn
R,
R,
when calculated according to the status of second limit
Status
T C V N 5 5 7 4 : 2 0 1 2
R a btn nd calculate the intensity of concrete ser b
, R, bt ser , MPa
C Hamlet reliability ch ị u dodge n of the b vise ng
Concrete
В1 В1,5 В2 В2,5 В3,5 В5 В7,5 В10 В12,5 В15 В20 В25 В30 В35 В40 В45 В50 В55 В60 M100 M150 M150 M200 M75 M50 M250 M350 M400 M450 M500 M600 M700 M700 M800 Axial compression (intensity prismatic)
R,bn
R,
Heavy concrete, concrete
-
-
-
-
-
-
-
2.7 3.6 5.5 7.5
9.5
11.0 15.0 18.5 22.0 25.5 29.0 32.0 36.0 39.5 43.0
9.5
11.0 15.0 18.5 22.0 25.5 29.0
granules Lightweight concrete
ser b
1.9 2.7 3.5 5.5 7.5
0.95 1.4 1.9 2.4 3.3 4.6 6.9 9.0
Concrete honeycomb
10.5 11.5
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.39 0.55 0.70 0.85 1.00 1.15 1.40 1.60 1.80 1.95 2.10 2.20 2.30 2.40 2.50
group A
-
-
-
-
0.39 0.55 0.70 0.85 1.00 1.15 1.40 1.60 1.80 1.95 2.10
group B
-
-
-
-
0.26 0.40 0.60 0.70 0.85 0.95 1.15 1.35 1.50
group C
-
-
-
-
-
-
-
0.29 0.39 0.55 0.70 0.85 1.00 1.15 1.40 1.60 1.80 1.95 2.10
-
-
-
-
-
-
-
0.29 0.39 0.55 0.70 0.85 1.00 1.10 1.20 1.35 1.50 1.65 1.80
-
-
-
-
-
-
-
-
Concrete heavy
Concrete small
-
-
particle
Pull shaft
R,btn
R, bt ser
-
-
-
-
-
1.15 1.40 1.60 1.80 1.95 2.10 2.20 2.30 2.40 2.50
aggregate Lightweight
characteristics
concrete
aggregate hollow
0.14 0.21 0.26 0.31 0.41 0.55 0.63 0.89 1.00 1.05
Concrete honeycomb
-
-
-
-
-
NOTE 1 Concrete Group granules see 5.1.1.3. NOTE 2: Symbol M to only concrete grade as stipulated before. The correlation between the value of concrete strength grade of concrete and A.1 and A.2 to the table, Appendix A of this standard.
NOTE 3: The values of concrete strength honeycomb panel with honeycomb concrete humidity is 10%. NOTE 4: For Expanded concrete - sand
R, bt ser
R a btn nd
Perlit Perlit aggregate value
NOTE 5: For hollow concrete value
nd R a bn
NOTE 6: For self-stressing concrete, value
R, nd R a bn
ser b
taken by the value of the lightweight concrete with porous aggregates particle multiplied by 0.85.
R,btn
taken as for lightweight concrete; Valid
R,
ser b
R, bt ser multiplied with 0.7. R,btn
taken as for heavy concrete, valid
R, bt ser multiplied with 1.2.
TCVN ...: 2011 R,
Table 13 - The strength of the concrete calculation b
R w bt hen calculated according to the first limit state, MPa
Level compressive strength of concrete
Status
Concrete
В1 В1,5 В2 В2,5 В3,5 В5 В7,5 В10 В12,5 В15 В20 В25 В30 В35 В40 В45 В50 В55 В60 M100 M150 M150 M200 M75 M50 M250 M350 M400 M450 M500 M600 M700 M700 M800
Axial compression
Heavy concrete, concrete
-
-
-
-
-
-
-
2.1 2.8 4.5 6.0
7.5
8.5 11.5 14.5 17.0 19.5 22.0 25.0 27.5 30.0 33.0
granules (intensity prismatic) Lightweight concrete
R b
1.5 2.1 2.8 4.5 6.0
0.63 0.95 1.3 1.6 2.2 3.1 4.6 6.0
Concrete honeycomb
-
7.5
8.5 8.5 11.5 11.5 14.5 14.5 17.0 17.0 19.5 19.5 22.0 22.0 --
7.0
7.7
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.26 0.37 0.48 0.57 0.66 0.75 0.90 1.05 1.20 1.30 1.40 1.45 1.55 1.60 1.65
Group A -
-
-
-
0.26 0.37 0.48 0.57 0.66 0.75 0.90 1.05 1.20 1.30 1.40 -
Group B -
-
-
-
0.17 0.27 0.40 0.45 0.51 0.64 0.77 0.90 1.00 -
group C -
-
-
-
-
-
-
0.20 0.26 0.37 0.48 0.57 0.66 0.75 0.90 1.05 1.20 1.30 1.40 -
-
-
-
-
-
-
0.20 0.26 0.37 0.48 0.57 0.66 0.74 0.80 0.90 1.00 1.10 1.20 -
-
-
-
-
-
-
Concrete NA ng
Concrete small particle
Pull shaft
-
-
-
-
-
-
-
0.75 0.90 1.05 1.20 1.30 1.40 1.45 1.55 1.60 1.65
aggregate
R bt Lightweight
characteristics
concrete
aggregate hollow
Concrete honeycomb
0.06 0.09 0.12 0.14 0.18 0.24 0.28 0.39 0.44 0.46 -
-
-
-
-
NOTE 1 Concrete Group granules see 5.1.1.3. NOTE 2: Symbol M to only concrete grade as stipulated before. The correlation between the value of concrete strength grade of concrete and A.1 and A.2 to the table, Appendix A of this standard.
-
TCVN ...: 2011 R,
Table 13 - The strength of the concrete calculation b
R w bt hen calculated according to the first limit state, MPa
Level compressive strength of concrete
Status
Concrete
В1 В1,5 В2 В2,5 В3,5 В5 В7,5 В10 В12,5 В15 В20 В25 В30 В35 В40 В45 В50 В55 В60 M100 M150 M150 M200 M75 M50 M250 M350 M400 M450 M500 M600 M700 M700 M800
Heavy concrete, concrete
Axial compression
-
-
-
-
-
-
-
2.1 2.8 4.5 6.0
7.5
8.5 11.5 14.5 17.0 19.5 22.0 25.0 27.5 30.0 33.0
granules (intensity prismatic) Lightweight concrete
R b
1.5 2.1 2.8 4.5 6.0
0.63 0.95 1.3 1.6 2.2 3.1 4.6 6.0
Concrete honeycomb
-
7.5
8.5 8.5 11.5 11.5 14.5 14.5 17.0 17.0 19.5 19.5 22.0 22.0 --
7.0
7.7
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.26 0.37 0.48 0.57 0.66 0.75 0.90 1.05 1.20 1.30 1.40 1.45 1.55 1.60 1.65
Group A -
-
-
-
0.26 0.37 0.48 0.57 0.66 0.75 0.90 1.05 1.20 1.30 1.40 -
Group B -
-
-
-
0.17 0.27 0.40 0.45 0.51 0.64 0.77 0.90 1.00 -
group C -
-
-
-
-
-
-
0.20 0.26 0.37 0.48 0.57 0.66 0.75 0.90 1.05 1.20 1.30 1.40 -
-
-
-
-
-
-
0.20 0.26 0.37 0.48 0.57 0.66 0.74 0.80 0.90 1.00 1.10 1.20 -
-
-
-
-
-
-
Concrete NA ng
Concrete small particle
Pull shaft
-
-
-
-
-
-
-
0.75 0.90 1.05 1.20 1.30 1.40 1.45 1.55 1.60 1.65
aggregate
R bt Lightweight
characteristics
concrete
aggregate hollow
Concrete honeycomb
0.06 0.09 0.12 0.14 0.18 0.24 0.28 0.39 0.44 0.46 -
-
-
-
-
-
NOTE 1 Concrete Group granules see 5.1.1.3. NOTE 2: Symbol M to only concrete grade as stipulated before. The correlation between the value of concrete strength grade of concrete and A.1 and A.2 to the table, Appendix A of this standard.
NOTE 3: The values of concrete strength honeycomb panel with honeycomb concrete humidity is 10%. NOTE 4: For Expanded concrete - sand
R t bt aken by the value of the lightweight concrete with porous aggregates particle multiplied by 0.85.
Perlit Perlit aggregate value
R t b aken as for lightweight concrete; Valid
NOTE 5: For hollow concrete value NOTE 6: For self-stressing concrete, value
R m bt ultiplied with 0.7.
R t b aken as for heavy concrete, valid
T C V N 5 5 7 4 : 2 0 1 2
R m bt ultiplied by 1.2.
4 1 4 1
TCVN 5574: 2012
Table 14 - calculated tensile strength of concrete bt
R W ith
level tensile strength of concrete, MPa Tensile strength level and corresponding marks
of concrete Status
Concrete
B t 0 .8 B t 1 .2 B t 1 .6 B t 2 .0 B t 2 .4 B t 2 .8 B t K 10 K15 K20 K25 K30 3.2 K35 K40
pull along
axis
Heavy concrete, concrete self-stress, small particles of concrete,
0.62 0.93 1.25 1.55 1.85 2.15 2.45
lightweight concrete
NOTE: Symbol of concrete K to just under tensile strength before.
Table 15 - Coefficient of working conditions of concrete
bi
• Coefficient of working
Factors to mention working conditions coefficient of concrete
conditions of concrete
TCVN 5574: 2012
Table 14 - calculated tensile strength of concrete bt
R W ith
level tensile strength of concrete, MPa Tensile strength level and corresponding marks
of concrete Status
Concrete
B t 0 .8 B t 1 .2 B t 1 .6 B t 2 .0 B t 2 .4 B t 2 .8 B t K 10 K15 K20 K25 K30 3.2 K35 K40
pull along
axis
Heavy concrete, concrete self-stress, small particles of concrete,
0.62 0.93 1.25 1.55 1.85 2.15 2.45
lightweight concrete
NOTE: Symbol of concrete K to just under tensile strength before.
Table 15 - Coefficient of working conditions of concrete
bi
• Coefficient of working
Factors to mention working conditions coefficient of concrete
conditions of concrete Symbol
1. Load loop 2. The nature of the long-term effects of the load:
• b
first
Value See Table 16
• b 2
a) When told to load frequently, temporary load long-term and temporary short-term, except for load short term effects that the total duration of their effects during use of small (eg load by crane, load of conveyor equipment; wind loads; loads appear during production, transport and erection, etc ..); as well as special mention loads cause uneven deformation, etc ..
- for heavy concrete, concrete granules, concrete and natural light curing steam curing concrete in environmental conditions: + Concrete ensure continued increase intensity over time (eg, water, damp soil or air humidity over 75%)
1.00
+ no concrete guarantees to continue increasing intensity over time (dry) 0.90 - for concrete honeycomb, hollow concrete does not depend on the conditions of use
0.85
b) As mentioned temporary load short (short-term effects) in combination under consideration or special load * not referred to in paragraph 2a, for concrete. 1.10 3. Pour the concrete vertically, each 1.5 m thick layer on to:
• b 3
- heavy concrete, lightweight concrete and concrete granules
0.85
-
0.80
honeycomb concrete and hollow concrete
4. Effects of biaxial stress state "compression-pull" to the concrete strength
42
• b 4
View 7.1.3.1
TCVN 5574: 2012 Table 15 - ( finish)
Coefficient of working conditions
Symbols of
Factors to mention working conditions coefficient of concrete
concrete 5. Pour concrete vertical column, the maximum size of the column size smaller than 30 cm
Value
• b 5
6. Phase prestressed structures
0.85
• b 6
a) when using steel fibers
+ for lightweight concrete
1.25
+ for other types of concrete
1.10
b) use of steel bars + for lightweight concrete
1.35
+ for other types of concrete
1.20
7. Structural Concrete
• b 7 • b 7
8. Structural Concrete made from high-strength concrete to mention coefficient
• b 8
0.90 0.3 + • • 1. Value • s ee
6.2.2.3 • b 9
9. Humidity of concrete honeycomb
+ 10% and smaller
1.00
+ greater than 25%
0.85
+ greater than 10% and less than or equal to 25%
linear interpolation
10. Concrete pouring insert joints when assembling components joint width less than 1/5 the size of
• b ten
components and less than 10 cm.
1.15
* When adding coefficient of working conditions in the event additional load special mention as directed by the relevant standards (eg when mention the earthquake load) is taken
• b 2 •
first ;
NOTE 1: Coefficient of working conditions: + taken as 1, 2, 7, 9: should be included when determining the intensity calculation
R,
+ taken under 4 should be included when determining the intensity calculation
+
also according to other sections: just mention when determining b
R a nd
b
bt ser
bt
R;
;
R.
NOTE 2: For the bearing structure of the load effects loop, coefficient
• b 2
be disregarded when calculating according to reliability, longer
• b
first
when the
calculated in accordance with fatigue and cracks forming conditions.
NOTE 3: When calculating the load-bearing structure in the stage pre-stressed, coefficient
• b 2 without mention.
NOTE 4: The coefficient of working conditions of concrete are included in the calculation are not interdependent, but their area is not less than 0.45.
43
TCVN 5574: 2012 R,
The strength of the concrete calculation when calculated according to the status of second limit
•
included in the calculation must be multiplied by the coefficient of working conditions bi
ser b
and
R,
bt ser
= 1; except in cases specified in
7.1.2.9, 7.1.3.1, 7.1.3.2. For other types of lightweight concrete, allowing use other values of str ength calculations, when approved according to regulations.
Allows use of value for all types of lightweight concrete when a firm basis. NOTE: For the value-level intermediate concrete durability under 5.1.1.3, the values shown in Table 12, 13 and 17 take the linear interpolation.
5.1.2.4 Value modulus of concrete initial
E c ompression and pulling taken according Table 17.
b
In case no data on type of cement, concrete components, production conditions etc .., lets take the other values of
b
E i s the competent authority for approval. •
5.1.2.5 Coefficient of thermal expansion
bt
when the temperature changes from minus 40 • C 50 • C, depending on the type of concrete
be obtained as follows:
•
For heavy concrete, concrete granules and lightweight aggregate concrete small dense type: 1 • ten- 5 o C- f irst;
•
For lightweight aggregate concrete small hollow type: 0.7 • ten- 5 o C- first;
•
For concrete and hollow concrete honeycomb: 0.8 • ten-
5 o
C- f irst.
In case no data on the mineral composition of aggregates, cement hydrated levels of concrete, lets take the values • bt other if there are grounds and the competent bodies approval. 5.1.2.6 Initial horizontal expansion coefficient of concrete • ( P oat-burn ratio) of 0.2 degrees for all types of concrete. Sliding modular concrete G 0 .4 degree value
E c b orresponding. Value of
E f or Table
b
17.
• b
Table 16 - Coefficient of working conditions of concrete first
Value Concrete moisture status of concrete 1. Concrete heavy
when the load-bearing structure repeat
• b with asymmetry coefficient of cycle first
From 0 to 0.1 0.2
0.3
•
b
0.4
0.5
0.6
0.7
Natural moisture
0.75
0.80 0.85
0.90
0.95
1.00
1.00
Water saturation
0.50
0.60 0.70
0.80
0.90
0.95
1.00
0.60
0.70 0.80
0.85
0.90
0.95
1.00
0.45
0.55 0.65
0.75
0.85
0.95
1.00
2. lightweight concrete Natural moisture
Water saturation
NOTE: In this table:
•
•
•
,
, with
•
bbb , max min
in a cycle of weight change determined as directed in 6.3.1.
44
•
b , min
,
•
b , max
respectively minimum and maximum stress of concrete
TCVN ...: 2011 Table 17 - Module initial elasticity of concrete compression and pulling, E b • ten-
3,
MPa
Compressive strength levels and corresponding marks
Concrete
B2,5 B3,5 B1,5 B1 B2 B15 B20 B5 B7,5 B10 B25 B30 B35 B12,5 B40 B45 B50 B55 B60 M100 M150 M150 M200 M75 M50 M250 M350 M400 M450 M500 M600 M700 M700 M800
Heavy concrete
natural curing
-
-
-
-
9.5 13.0 16.0 18.0 21.0 23.0 27.0 30.0 32.5 34.5 36.0 37.5 39.0 39.5 40.0
steam curing at
-
-
-
-
8.5 11.5 14.5 16.0 19.0 20.5 24.0 27.0 29.0 31.0 32.5 34.0 35.0 35.5 36.0
autoclaved
-
-
-
-
7.0 9.88 12.0 13.5 16.0 17.0 20.0 22.5 24.5 26.0 27.0 28.0 29.0 29.5 30.0
natural curing
-
-
-
-
7.0 10.0 13.5 15.5 17.5 19.5 22.0 24.0 26.0 27.5 28.5 - -
steam curing at
-
-
-
-
6.5 9.0 12.5 14.0 15.5 17.0 20.0 21.5 23.0 24.0 24.5 -
natural curing
-
-
-
-
6.5 9.0 12.5 14.0 15.5 17.0 20.0 21.5 23.0
-
-
steam curing at
-
-
-
-
5.5 8.0 11.5 13.0 14.5 15.5 17.5 19.0 20.5
-
-
-
-
-
-
D800
-
-
-
4.0 4.5 5.0 5.5
D1000
-
-
-
5.0 5.5 6.3 7.2 8.0
D1200
-
-
-
6.0 6.7 7.6 8.7 9.5 10.0 10.5
D1400
-
-
-
7.0 7.8 8.8 10.0 11.0 11.7 12.5 13.5 14.5 15.5
D1600
-
-
-
-
D1800
-
-
-
-
-
D2000
-
-
-
-
-
atmospheric pressure
A Concrete
-
-
-
-
-
-
-
-
-
-
-
-
-
atmospheric pressure small particle group
B
atmospheric pressure C autoclaved Lightweight concrete and
-
-
-
-
-
16.5 18.0 19.5 21.0 22.0 23.0 23.5 24.0 24.5 25.0
-
-
-
-
-
-
-
-
-
-
-
-
8.4
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
hollow concrete, with marking according to the average density
9.0 10.0 11.5 12.5 13.2 14.0 15.5 16.5 17.5 18.0 11.2 13.0 14.0 14.7 15.5 17.0 18.5 19.5 20.5 21.0 -
14.5 16.0 17.0 18.0 19.5 21.0 22.0 23.0 23.5 -
4
5
T C V N 5 5 7 4 : 2 0 1 2
TCVN ...: 2011 f o r t y
Table 17 - ( finish)
s i x
Concrete
Compressive strength levels and corresponding marks
B2,5 B3,5 B1,5 B1 B2 B15 B20 B5 B7,5 B10 B25 B30 B35 B12,5 B40 B45 B50 B55 B60 M100 M150 M150 M200 M75 M50 M250 M350 M400 M450 M500 M600 M700 M700 M800 Light concrete and autoclaved
D500
1.1 1.4
-
D600
1.4 1.7 1.8 2.1
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
concrete honeycomb, which marks block
The average volume
D700
-
1.9 2.2 2.5 2.9
D800
-
-
-
D900
-
-
-
-
D1000
-
-
-
-
-
D1100
-
-
-
-
-
-
D1200
-
-
-
-
-
-
NOTE 1: Classification of concrete granules group see 5.1.1.3.
2.9 3.4 4.0 3.8 4.5 5.5
5.0 6.0 7.0 6.8 7.9 8.3 8.6 -
8.4 8.8 9.3
T C V N 5 5 7 4 : 2 0 1 2
T C V N 5 5 7 4 : 2 0 1 2
TCVN ...: 2011 f o r t y
Table 17 - ( finish)
s i x
Concrete
Compressive strength levels and corresponding marks
B2,5 B3,5 B1,5 B1 B2 B15 B20 B5 B7,5 B10 B25 B30 B35 B12,5 B40 B45 B50 B55 B60 M100 M150 M150 M200 M75 M50 M250 M350 M400 M450 M500 M600 M700 M700 M800 Light concrete and autoclaved
D500
1.1 1.4
-
D600
1.4 1.7 1.8 2.1
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
concrete honeycomb, which marks block
The average volume
D700
-
1.9 2.2 2.5 2.9
D800
-
-
-
D900
-
-
-
-
D1000
-
-
-
-
-
D1100
-
-
-
-
-
-
D1200
-
-
-
-
-
-
2.9 3.4 4.0 3.8 4.5 5.5
5.0 6.0 7.0 6.8 7.9 8.3 8.6 -
8.4 8.8 9.3
NOTE 1: Classification of concrete granules group see 5.1.1.3. NOTE 2: Symbol M to only concrete grade as stipulated before. The correlation between the value of concrete strength grade of concrete and A.1 and A.2 to the table, Appendix A of this standard.
E ab ccording to linear interpolation. For concrete honeycomb not
NOTE 3: For lightweight concrete, concrete honeycomb, hollow concrete volume average volume in between, take autoclaved, the value
E t aken as for autoclaved concrete, then multiply by a factor of 0.8. b
NOTE 4: For self-stressing concrete, value
E taken as for heavy concrete, then multiplied by the coefficient b
• = 0.56 + 0,006B, with B is superior compressive strength of concrete.
TCVN 5574: 2012
CIV 5.2 Frame 5.2.1 Classification of reinforced and the scope of use
5.2.1.1 Steel reinforcement for reinforced concrete structures to ensure the t echnical requirements under the current standards of the State. According to ISO 1651: 1985, has the kind of reinforcement and reinforced CI Smooth ribbed (reinforced rebar) CII, CIII, C IV. TCVN 3101: 1979 with the kind of low-carbon steel wire c old drawn. TCVN 3100: 1979 has rounded steel fiber reinforced concrete used for prestressed. In this standard may include all kinds of steel imports from Russia, consists of the following categories:
a) Reinforcement steel bar:
•
Hot rolled: rolled: Smooth group AI, AI, A-II A-II with with Burt Burt group and A C- II, A-III, A-IV, AV, A-VI;
•
Reinforced body heat and heat: ribbed Group A T- IIIC, A T- IV, A T- I VC, A T- I VK, A T-
DM, A T- V I, A T- V IK and A T- V II. b) Reinforced fiber types:
•
Cold-drawn steel fibers:
TCVN 5574: 2012
CIV 5.2 Frame 5.2.1 Classification of reinforced and the scope of use
5.2.1.1 Steel reinforcement for reinforced concrete structures to ensure the t echnical requirements under the current standards of the State. According to ISO 1651: 1985, has the kind of reinforcement and reinforced CI Smooth ribbed (reinforced rebar) CII, CIII, C IV. TCVN 3101: 1979 with the kind of low-carbon steel wire c old drawn. TCVN 3100: 1979 has rounded steel fiber reinforced concrete used for prestressed. In this standard may include all kinds of steel imports from Russia, consists of the following categories:
a) Reinforcement steel bar:
•
Hot rolled: rolled: Smooth group AI, AI, A-II A-II with with Burt Burt group and A C- II, A-III, A-IV, AV, A-VI;
•
Reinforced body heat and heat: ribbed Group A T- IIIC, A T- IV, A T- I VC, A T- I VK, A T-
DM, A T- V I, A T- V IK and A T- V II. b) Reinforced fiber types:
•
•
Cold-drawn steel fibers:
+
Plain: ribbed Bp-I group;
+
High intensity type: Plain B-II, ribbed Bp-II group.
+
7 fiber type K-7, K-19 type 19 fibers.
Steel cable:
In the reinforced concrete structure, which allows using methods increase the intensity by dragging the group A-III bars B i n the industrial chain (controlled elongation and stress or just controlled elongation). The use of new types of steel production should be the competent authority for approval.
NOTE 1: For the Russian steel, the symbol "C" demonstrates "weld" (eg AT-IIIC); letter "K" represents the resistance to corrosion (eg AT-IVK); "T" symbol used in high-strength steel (eg AT-V). In case of welded steel is required to have corrosion resistance and then used the symbol "CK" (eg AT-DM). Symbol "c" refers to steel with special indications (eg AC-II).
NOTE 2: From now on, in the prescribed use of steel, the order of the steel group demonstrates the priority when applying. For example: in the record 5.2.1.3 " Should use reinforced CIII group, A-III, AT-IIIC, AT-IVC, Bp-I, CI, AI, CII, A-II and AC-II in forced steel frame and mesh " means the order of priority when used will be: CIII, then to AIII, AT-IIIC and etc ..
To make reservation details available and the connection of the hot-rolled steel needed or standard steel design steel structure TCXDVN 338: 2005. These steels are produced according to the standards of other countries (including the steel is produced in the joint venture) must comply with the technical requirements of the relevant standards and have said Technical indicators Main as follows:
•
Chemical composition and manufacturing methods to meet the requirements of the steel used in construction;
•
Indicators of intensity: yield, limited durability and coefficient of variation of those limits;
•
Elastic modulus, elongation extreme, ductility;
•
Weldability are; 47
TCVN 5574: 2012
•
Bearing structures with high or low temperatures need to know the change of mechanical properties when the temperature rises and falls;
•
With load-bearing structures repeat Know fatigue limit.
NOTE: For other types of reinforcing steel in accordance with ISO should not be based on the criteria for conversion of the mechanical equivalent reinforced when choosing the scope of their use (see Appendix B).
5.2.1.2 The selection depends on the type of reinforced structure, whether or not pre-stressed, as well as construction conditions and use of buildings and structures, according to instructions from 5.2.1.3 to 5.2.1.8 and having regard to unity goods used for structural reinforcement in groups and diameter, etc ..
5.2.1.3 So do not stretch reinforcement (reinforced) for reinforced concrete structures, use the following types of steel:
a)
A group of steel bar T- I VC: used as reinforcement along;
b)
Steel bar CIII group, A-III and A T- IIIC: used as reinforced vertical and horizontal reinforcing steel;
c)
Bp-strand steel group I: for use as reinforced vertical and horizontal reinforcing steel;
d)
Steel bars CI group, AI, CII, A-II and AC-II used as transverse reinforcement as well as longitudinal reinforcement (if such can not be
used other ordinary steel);
e)
CIV group of steel bars, A-IV (A-IV, (A-IV, A T- IV, A T- I VK): used as reinforcement along the steel frame and mesh force;
f)
Rebar group AV (AV, A T- V, A T- VK, A T- DM), A-VI (A-VI, A T- VI, A T- VIK), A T- V II used as reinforcement longitudinal compressive, also
used as reinforcement longitudinal compressive and tensile in the case arranged both reinforced and reinforced steel frame stretch in force and wire mesh. So do not stretch reinforced, allowing the group to use reinforced A-III B l ongitudinal tensile steel reinforcement in steel frame and mesh force.
Should use reinforced CIII group, A-III, A T- IIIC, A T- I VC, Bp-I, CI, AI, CII, A-II and AC-II in forced steel frame and mesh.
Allows use as mesh and welded steel frame reinforced types of group A-III B, A T- I VK (made from steel grade 10MnSi2, 08Mn2Si) and A TV (made from steel grade 20MnSi) in link with spot welding Cross (cf. 8.8.1). 5.2.1.4 In the structure using reinforced, pressure steam, liquids and bulk materials, steel reinforcement bars should use the CI group, AI, CII, A-II, CIII, A-III and A T- I IIC and steel fibers Bp-I group. 5.2.1.5 For the tensile reinforcement for reinforced concrete structures, need to use the following types of steel:
a)
rebar group AV (AV, A T- V, A T- V K, A T- D M), A-VI (A-VI, A T- VI, A T- V IK) and A T- V II;
b)
steel fiber fiber B-II B-II group, group, Bp-II; steel cable cable and and K-7 and and K-19. Allow the the use of steel steel bars bars CIV group, A-IV (A-IV, A T- IV, A T- I VC, A T- I VK)
and A-III B r einforcing stretch.
In structures with length not greater than 12 meters should prioritize the use of reinforcement bars Group A T- V II, A T- V I and A T- V.
NOTE: To make tensile reinforcement for reinforced concrete structures prestressed concrete made from lightweight B7,5 to B12,5 level, use the following types of steel bar: CIV, A-IV (A -IV, AT-IV, AT-IVC, AT-IVK) and A-IIIB.
48
TCVN 5574: 2012
5.2.1.6 For the tensile reinforcement for structural pressure steam, liquids and bulk materials should use the following types of steel:
a)
Group B-II steel strand, steel cable Bp-I and K-7 and K-19;
b)
Rebar group AV (AV, A T- V, A T- VK, A T- D M), A-VI (A-VI, A T- VI, A T- VIK) and A T- VII;
c)
CIV group of steel bars, A-IV (A-IV, A T- IV, A T- I VK, A T- I VC). In the above
structural steel also allows the use of group A-III B. For the tensile reinforcement in the structural work in the aggressive environments should strongly preferred steel used CIV group, A-IV, as well as all kinds of steel Group A T- V IK, A T- V K, A T- DM and A
T- I VK.
5.2.1.7 When choosing the type and grade of steel reinforcing placed as calculated, as well as selection of steel roll-formed for the details in place to mention the temperature conditions of use of the structure and nature of the load as required in Annexes A and B.
5.2.1.8 For the hook of the concrete structure and assembly of reinforced concrete should use this type of hot rolled steel rod Ac-II marks 10MnTi group and CI group, AI grade C T 3 сп2.
5.2.1.9 In this standard, from here onwards, while not necessary to specify the type of steel bars (hot rolled, heat), symbol steel group use of symbols of reinforcing steel, hot-rolled (eg steel group AV understood is reinforced AV group, A T- V, A T- V K and A T- DM).
5.2.2 Characteristics specific criteria and calculation of reinforced 5.2.2.1 Intensity of reinforcing steel standards
R i sSN the smallest value of restricted flow control
actual or conventional (by stress to the residual deformation of 0.2%). Featured above is control of reinforcement is taken under the existing state standards and technical conditions of steel reinforcement ensures the probability of not less than 95%. Intensity standards SN R o f certain types of steel bars and fiber for in Table 18 and Table 19; for some other steel types, see Appendix B. 5.2.2.2 Tensile strength calculations
R r einforcement of the calculation according to the second limit state S
and second is defined by the formula:
•
RR
(ten)
• s
sn s
Inside:
• S is the coefficient of reliability of reinforced, taken from Table 20. For other steel grades, see Appendix B.
49
TCVN 5574: 2012
Table 18 - Standard tensile strength SN
R a nd tensile strength calculations
of rebar when calculated according to the status of second limit Value
Group rebar
R, R,
R aSN nd
CI, AI
235
CII, A-II
295
CIII, A-III
390
CIV, A-IV
590
AV
788
A-VI
980
AT-VII
ser s
ser s
, MPa
1175
A-IIIB
540
NOTE: symbol group 5.2.1.1 and 5.2.1.9 of steel t aken from.
Table 19 - Standard tensile strength SN
R a nd tensile strength calculations
R,
of steel fibers when calculated according to the status of second limit Strand steel group
Bp-I
B-II
Bp-II
Grade reliability
Diameter, mm
-
Value
3; 4; 5
R,
R aSN nd
490
1500
3
1500
1400
4; 5
1400
1300
6
1300
1200
7
1200
1100
8
1100
1500
3
1500
1400
4; 5
1400
1200
6
1200
1100
7
1100
1000
8
1000
1500
6; 9; twelfth
1500
1400
15
1400
1500
14
1500
K-7 K-19
NOTE 1: Supply of steel fiber strength is the value of the conventional yield, measured in MPa. NOTE 2: For steel fiber B-II group; Bp-II, K-7 and K-19 in symbols indicate reliability, for example: - Symbol Symbol B-II B-II steel steel fibers fibers with with aa diameter diameter of of 33 mm: mm: •• 3B1 500 500 - Steel symbol Bp-II Bp-II group group fiber fiber diameter diameter 5mm: 5mm: •• 5Bp1 5Bp1 400 400 - Symbol K-7 group of steel cable with a diameter of 12 mm: • 12K7-1 500
50
ser s
ser s
, MPa
TCVN 5574: 2012
•
Table 20 - Coefficient of reliability of reinforced S
Value
• S While structural calculations according to limit state
Group rebar first Rebar CI, AI, CII, A-II
Monday
1.05
1.00
1.10
1.00
1.07
1.00
CIV, A-IV, AV
1.15
1.00
A-VI, AT-VII AT-VII
1.20
1.00
1.10
1.00
1.20
1.00
1.20
1.00
1.20
1.00
1.20
1.00
6 to 8
CIII, A-III diameter, mm
From 10 to 40
controlled elongation and stress A-IIIB only controlled elongation
Bp-I steel fibers B-II, Bp-II Steel cables K-7, K-19 NOTE: symbol group 5.2.1.1 and 5.2.1.9 of steel taken from.
5.2.2.3 Compressive strength of reinforced calculations
R u sed in structural calculations according to the gender status
sc
The first term when the bond between the concrete and reinforced taken according to Table 21 and Table 22. When calculating
R t sc ake not more than 330 MPa big, also for steel
the period prior compressed texture, value
Group A-III B t aken by 170 MPa. When there is no cohesion between the concrete and reinforced grab
sc
R = 0.
5.2.2.4 Intensity of reinforcement calculation when calculated according to the first limit state is reduced (or increased) by multiplying by •
a factor of working conditions of reinforcement si
. This coefficient mention
the danger of destruction because of fatigue, the uneven stress distribution in cross section, anchoring conditions, the intensity of the surrounding concrete reinforcement, etc .., or the reinforcement work in conditions of great stress more conventional liquid limit, change the nature of the steel due to production conditions, etc .. the intensity of reinforcement calculation when calculated according to the status of second limit
R, Accounting coefficient of working conditions si
taken into
• = 1.0. R i ssw reduced compared
Calculating intensity of the horizontal rebar (reinforcing steel reinforced belt and oblique)
R by multiplying the coefficient of working conditions S
d)
ser s
first
Do not depend on the type and steel grade: grab
• S
and 2 • S
• S = 0.8 ( first
. The figures are taken as follows: • S mention the uneven stress distribution first
in reinforced);
51
TCVN 5574: 2012
Table 21 - The strength of the reinforcing steel bar calculation when calculating
according to the first limit state Tensile strength, MPa Strength Reinforced vertical
Group rebar
Horizontal reinforcement (reinforced belt, reinforced
R S
compressed
R sc
R sw
oblique)
CI, AI
225
175
225
CII, A-II
280
225
280
355
285 *
355
CIII, A-III diameter, mm From 10 to 40
365
290 *
365
CIV, A-IV
510
405
450 **
AV
680
545
500 **
A-VI
815
650
500 **
AT-VII
980
785
500 **
490
390
200
450
360
200
A-III diameter, diameter, mm
6 to 8
controlled elongation and stress
A-IIIB
only controlled elongation *
In welded steel steel frame, reinforced reinforced with steel steel belt CIII group, group, A-III has a diameter diameter smaller smaller than 1/3 the diameter diameter reinforced reinforced along the value
R sw = 255 MPa. **
Values
R a sc bove are given for structures made of heavy concrete, concrete granules, lightweight concrete when included in calculation 400 R = sc
computing loads taken under 2a in Table 15; While mention of the load taken under section 2b in Table 15, the value MPa. For structures made of concrete and hollow concrete honeycomb, in any event take
R sc = 400 MPa.
NOTE 1: In any case, if for any reason, reinforced non-stretch group CIII, A-III or higher is used as a steel rod horizontal (reinforced belt, or reinforced oblique), intensity values calculated accounting
sw
NOTE 2: Symbol 5.2.1.1 and 5.2.1.9 steel group view.
52
R a s for steel grab CIII group, A-III.
TCVN 5574: 2012
Table 22 - Strength of reinforced fiber calculated when calculated according to the state
The first limit, MPa Tensile strength calculations Compressive strength
Steel fiber Strand steel group
Reinforced vertical
(reinforced belt, reinforced
R S
3; 4; 5
410
R sc
R sw
oblique)
Bp-I
calculations
Horizontal reinforcement
diameter, mm
375 **
290 *
B-II level reliability 1500
3
1250
1000
1400
4; 5
1170
940
1300
6
1050
835
1200
7
1000
785
1100
8
915
730
Bp-II level reliability 1500
3
1250
1000
1400
4; 5
1170
940
1200
6
1000
785
1100
7
915
730
1000
8
850
680
500 **
K-7 grade reliability
1500
6; 9; twelfth
1250
1400
15
1160
K-19
14
1250
945 1000
hould take in 325 MPa. R ssw
* When using using steel fibers in in a steel frame tie, value ** Valu Values es
1000
are taken into account when calculating the texture made of heavy concrete, concrete granules, lightweight concrete bear the load R a bove sc
R sc = 4 00 MPa
weight taken as 2a in Table 15; when calculating the load-bearing structure according to 2b in Table 15 take the value
R taken as follows: for sc
as well as the calculation of structures made of concrete and hollow concrete honeycomb bear all load types, values
with steel fibers Bp-I earned 340 MPa, for B-II, Bp-II, K-7 and K-19: take by 400 MPa.
a)
For steel bar CIII CIII group, A-III has a diameter smaller than than 1/3 the diameter diameter reinforced reinforced with with steel steel fibers along and for Bp-I Bp-I group group
in welded steel frame:
• S 2 = 0.9 (
• S 2 including the ability to link to welding ruined
crispy).
Tensile strength calculations horizontal reinforcement (reinforced and reinforced belt oblique)
working conditions
• S
first
and 2 • S
In addition, the intensity calculation S
R t aking into account the system sw
above shown in Table 21 and Table 22. R,
R,sc
R i n the respective cases should be multiplied by the sw
coefficient of working conditions of reinforcement. The figures are given in Table 23 to Table 26.
53
TCVN 5574: 2012
•
Copy g 23 - The coefficients conditions the reinforcement of si
Values
Factors to mention the coefficient
Characterized by of working conditions reinforced
core group
steel
1. Reinforced shear
Horizontal reinforcement
Value
Symbol
reinforcement of
All groups
• si
• S
View 5.2.2.4
• S 2
View 5.2.2.4
first
reinforced CIII transverse reinforcement, A-III; BP-
2. solder connections when shear
I
reinforcement
3. Load loop
Reinforced vertical and horizontal reinforcement
4. solder connections when load
Reinforced vertical and
loop
horizontal reinforcement when link
All groups
See Table 24
• S 3
reinforced CI, AI, CII, A-
See Table 25
• S 4
II, CIII, A-III, CIV, A-IV; AV
solder
5. The stress transmitted to the
• S 5
Reinforced vertical
anchor and not reinforced rebar
strained
ll x p
anchor piece does not stretch
l is the distance
Inside: x
since the stress transmission period to calculate the cross section;
All groups l, security l p
reinforced
ll x
Not reinforced along
security
respectively the length of
the TV anchor stresses and
the stretch
reinforced areas (see 5.2.2.5 and 8.5.2) 6. Reinforced high intensity work in
Reinforced along bear
stress conditions greater than
drag
conventional liquid limit
CIV, A-IV; AV; A-VI; ATVII;
• S 6
B-II; K-7;
See Article 6.2.2.4
K-19 Horizontal reinforcement CI, AI; Bp-I
7. Metal structures made of lightweight
• S 7
concrete and lower grade B7,5
Reinforced along bear
8. constructions made of concrete honeycomb B7,5 and lower levels
compressed
Horizontal reinforcement
• S 8 All groups reinforced
0.8
• 40 190 B • 1 R sc B
25 • 1
R sw Reinforced along bear
9. Protection class reinforcement in concrete structures made from
compressed
All groups
• S 9
reinforced
See Table 26
honeycomb
NOTE 1: The factor
• S 3
and
• S 4
under section 3 and 4 of this table is only included in the calculation fatigue; for reinforcement
connected by link welding, coefficients above are included simultaneously. NOTE 2 Coefficient
• S 5 under section 5 of this table used for calculating intensity
NOTE 3: In the formula in Section 8 of this table, values compressive concrete, MPa) obtained in 5.1.1.2.
54
R and prestressed reinforced in
S
R and sc
sp
in MPa; value B (grade reliability R calculated sw
•
.
TCVN 5574: 2012
• S
Table 24 - Coefficient of working conditions of reinforcement 3
Value
when the load-bearing structure repeat
• S 3 with asymmetric coefficients of cycle S
Group Reinforced
• equal
- 1.0 -0.2 0 0.2 0.4 0.7 0.8 0.8 0.9 0.9 1.0 CI, AI
0.41 0.63 0.70 0.77 0.90 1.00 1.00 1.00 1.00
CII, A-II
0.42 0.51 0.55 0.60 0.69 0.93 1.00 1.00 1.00
A-III diameter, mm
6 to 8
CIII, A-III diameter, mm
0.33 0.38 0.42 0.47 0.57 0.85 0.95 1.00 1.00
From 10 to 40
0.31 0.36 0.40 0.45 0.55 0.81 0.91 0.95 1.00
CIV, A-IV
-
-
-
-
0.38 0.72 0.91 0.96 1.00
AV
-
-
-
-
0.27 0.55 0.69 0.87 1.00
A-VI
-
-
-
-
0.19 0.53 0.67 0.87 1.00
AT-VII
-
-
-
-
0.15 0.40 0.60 0.80 1.00
Bp-II
-
-
-
-
-
0.67 0.82 0.91 1.00
B-II
-
-
-
-
-
0.77 0.97 1.00 1.00
-
-
-
-
-
0.77 0.92 1.00 1.00
-
-
-
-
-
0.68 0.84 1.00 1.00
K-19, diameter 14 mm
-
-
-
-
-
0.63 0.77 0.96 1.00
Bp-I
-
-
-
-
-
-
0.41 0.66 0.84 1.00 1.00
-
-
-
-
0.46 0.73 0.93 1.00 1.00
K-7
6 to 9
diameter, mm
From 12 to 15
0.56 0.71 0.85 0.94 1.00 1.00 1.00
controlled elongation and stress
A-IIIB
just check stress
• •
NOTE 1:
•
, min
•
, Inside
S , min
,
•
respectively minimum and maximum stress in the reinforcement of a
S , max
• sss, max cyclical changes in the load, which is determined in accordance with 6.3.1.
NOTE 2: When calculating the bending structure made of reinforced concrete and weighs no tension, for taking vertical reinforcement as follows:
+ when
min
•
0 0•
, 20
MMmax + when
0, 20
min
•
MM max + when
min
•
0, 75
MM max Inside
MM min
max,
•
0, 75
• S •
• S •
• S •
0,
30;
•0 15,
0,
min
8
;
MM max min
,
MM max
respectively bending moment in the smallest and largest cross-sectional area in a cycle calculation of load changes
important.
NOTE 3: Given values
• S indicated in the table without value
• S 3
do not allow the use of the corresponding type of reinforcement
55
TCVN 5574: 2012
• S
Table 25 - Coefficient of working conditions of reinforcement 4
When the load-bearing structure loop asymmetry coefficient of
cycle S
Group links core group
• equal
solder
steel
0
0.2
0.4
0.7
0.8
0.9
1.0
first
0.90
0.95
1.00
1.00
1.00
1.00
1.00
CI, AI
2
0.65
0.70
0.75
0.90
1.00
1.00
1.00
CII, A-II
3
0.25
0.30
0.35
0.50
0.65
0.85
1.00
4
0.20
0.20
0.25
0.30
0.45
0.65
1.00
first
0.90
0.95
1.00
1.00
1.00
1.00
1.00
2
0.60
0.65
0.65
0.70
0.75
0.85
1.00
3
0.20
0.25
0.30
0.45
0.60
0.80
1.00
4
0.15
0.20
0.20
0.30
0.40
0.60
1.00
first
-
-
0.95
0.95
1.00
1.00
1.00
2
-
-
0.75
0.75
0.80
0.90
1.00
3
-
-
0.30
0.35
0.55
0.70
1.00
first
-
-
0.95
0.95
1.00
1.00
1.00
2
-
-
0.75
0.75
0.80
0.90
1.00
3
-
-
0.35
0.40
0.50
0.70
1.00
CIII, A-III
CIV, A-IV
AV HR
NOTE 1: The group of associated welding mentioned in this list include: + Group 1 - link confrontation welding steel bars (A-II, CII, A-III, CIII, A-IV, CIV, AV) with a diameter of the same, with mechanical processing before or after welding; + Group 2 - linking the two intersecting steel bars welded cross by exposure; link confrontation of two welded steel bars (AI, CI, A-II, CII, A-III, CIII) have the same diameter and are beveled head; + Group 3 - 3 steel welded links (A-IIIC) overlap (3 layers) type weld cross by exposure; link welding confrontation of the two bars (A-III, CIII) pair close together; link confrontation of two welded steel bar steel trough; Welding the two bars linked (AI, CI, A-II, CII, A-III, CIII, A-IV, CIV, AV) with two segments connected with weld steel bar across the entire steel clip connector; link welded steel T-bar and the exposed steel with welded joints;
+ Group 4 - link welded steel husband (AI, CI, A-II, CII, A-III, CIII) and the exposed steel by welding, arc welding; link welding of steel bars with a T-arc welds and no metal parts; NOTE 2: In the table for values
NOTE 3: Value coefficient 10% larger diameter 32 mm steel bars.
56
• S 4 for reinforcement to 20 mm diameter. • S 4 should be reduced to 5% if the diameter is 22 mm steel bars up to 32 mm and dropped
TCVN 5574: 2012
Table 26 - Coefficient of working conditions
9
• S
reinforcement of
Value
• S 9
reinforcement of
Protection class
smooth 1. POLISTIROL cement, mineral paint
flanged
1.0
1.0
0.7
1.0
0.7
0.7
3. Bi tum-silicate (hot)
0.7
0.7
4. Bi tum-clay
0.5
0.7
5. bituminous shale, cement
0.5
0.5
2. Cement-bituminous (cold) when
Greater or equal to 6 mm
diameter rebar Less than 6 mm
l R einforced stretch of no anchor defined by
5.2.2.5 The length of the transmitted stress p formula:
• • • • • • •
Inside p
and p •
• Rl sp p pp
• • • bp • d • •
(11)
taken from Table 27.
In case of necessity, value
R s bp hould be multiplied by the coefficient of working conditions of concrete,
• b .
except 2 Value
•
•
greater value of the two values
•
value
sp
in formula (11) is removed by:
•
sp
R aS nd
sp
•
when calculated according to reliability;
when calculating the components according crack resistance. here,
•
sp
taken have included amortization
losses under the stress calculation formula from 1 to 5 in Table 6. In the concrete structures made from small particles of Group B and lightweight aggregate concrete small hollow type (except concrete B7,5 to B12,5 level),
•
value
p and p •
take increased 1.2 times compared with the values given in Table 27.
In the case before transmission tensioning sudden compression in concrete, ribbed rebar for the values
•
p
and p •
taken increased 1.25 times. Do not allow stress transfer before the sudden compression when using
Its rebar larger diameter 18 mm. For ribbed steel bars of all groups, values p
l take not less than d
15.
57
TCVN 5574: 2012
For steel fibers (except steel fiber high intensity group Bp-II has anchored within buckling length), the start point of the segment induces stresses in the case of stress transfer compressed abruptly into concrete taken from the point from the beginning sucking components a
l.
distance of 0.25 p
l
Table 27 - The coefficients for determining the length of the transmitted stress p
Reinforced stretch of no anchor Coefficients
Diameter Type and steel group
mm
1. ribbed steel bars (all steel group)
•
• p
p
Not dependent sugar 0.25
ten
5
1.40
40
4
1.40
50
3
1.40
60
15
1.00
25
twelfth
1.10
25
9
1.25
30
6
1.40
40
14
1.00
25
glasses
2. Steel fiber ribbed high strength Bp-II group
K-7 3. Steel Cable
K-19
•
NOTE: For structures made of lightweight concrete with levels from B7,5 to the values B12,5
p and p •
1.4 times higher than the corresponding values in this table.
E of some kind of reinforcement in Table 28.
5.2.2.6 Modulus values
S
Table 28 - Module elastic reinforcement of some kind Group Reinforced
E
S
• ten •
4
CI, AI, CII, A-II
21
CIII, A-III
20
CIV, A-IV, AV, A-VI and AT-VII
19
A-IIIB
18
B-II, Bp-II
20
K-7, K-19
18
Bp-I
17
58
, MPa
taken increased
TCVN 5574: 2012
6 Calculation of concrete structures, reinforced concrete according to the first limit state 6.1
Calculated in accordance with concrete structure durability
6.1.1 General Principles 6.1.1.1 Calculate concrete structures according to reliability should be carried out on the section perpendicular to the longitudinal axis structures. Depending on the working conditions of the structures, which in computing mention or not mention the work of regional tension.
6.1.1.2 For the eccentric compressive structures referred to in 4.1.7a that limit state is characterized by the destruction of concrete under compression, when calculating not to mention the work of concrete in tension. Compressive s trength of conventional concrete is R
the compressive stress of concrete, with a value equal b
and evenly distributed across the cross section compressive - compressive convention area (Figure 2) and hereinafter referred to as the compression resistance of the concrete.
R b
A b
N
x R b A b
h y
White t © m tiOt Dion
b
Figure 2 - Map of the internal forces and stresses chart on sections perpendicular to the longitudinal axis compressive concrete structure when calculated eccentricity reliability
not to mention the work of concrete tensile zone 6.1.1.3 For structures outlined in 4.1.7b, as well as the structures do not allow cracking under the conditions of use of texture (pressure water structures, eaves, walls, etc ..) when computing mention the work of concrete tensile zone. Meanwhile limit state is characterized by the destruction of concrete in tension zones (cracks appear). Critical power is determined based on the following assumptions (Figure 3):
•
Section is still considered flat after deformation;
•
Elongation largest relative of concrete tensile fibers outermost degree
•
Stresses in the concrete compressive zone is determined with the elastic deformation of concrete (in some cases including
2
bt er b
;
inelastic deformation); •
Stress concrete tensile zone is is evenly evenly distributed distributed and by by
R;
bt
6.1.1.4 While capable of forming cracks oblique (eg Structure section the letter i, T shear), to calculate concrete structures under the conditions (144) and (145), in which the intensity concrete calculations when calculated according to the status of second limit R,
ser b
corresponding calculate when calculated according to the first limit state
and
R,
bt ser
is replaced by the intensity values R ab nd
bt
R;
59
TCVN 5574: 2012
6.1.1.5 In addition, the components should be calculated under the local effect of the load according to 6.2.5.1.
N
A b r u o h
M
x
A bt R bt
b
2R bt
Figure 3 - Map of the internal forces and stresses chart on sections perpendicular to the longitudinal axis structure
bending concrete (compression eccentricity) is calculated according to reliability,
can mention the work of concrete tensile zone
6.1.2 Calculation of concrete structures under compression eccentric
6.1.2.1 When calculating compressive eccentric structures, should take into account the random eccentricity a
Value
e the vertical force.
e i a s determined according to 4.2.12.
6.1.2.2 When the piece of structures
0•
il
14 , need to consider the influence of curvature in the plane of deflection
and in the center of power along with its plane perpendicular to the bearing capacity of the components by multiplying the value of
0
e c oefficient • ( s ee 6.1.2.5). In case outside the plane calculated eccentricity of vertical force, value
e t 0aken by random eccentricity
e.
a
Do not allow the use of concrete structures under compression eccentric (except the cases mentioned in 4.1.7b) when the eccentricity of axial
e e 0 xceed:
force setpoint told to buckling •
a)
Under load combination:
•
Basic: ............................................... .................................................. ..................... 0,90y
•
Special: ............................................... .................................................. .................... 0,95y
b)
By type and level concrete:
•
With heavy concrete, concrete and lightweight concrete granules have greater levels B7,5: .................... y-10
•
With concrete and other concrete level: ........................................ ................................. y-20 (here, y is the distance
from the central section to concrete fibers more compressible, in mm). 6.1.2.3 For concrete structures under eccentric compression mentioned in 8.11.2, needs structural reinforcement. 6.1.2.4 Concrete structures under eccentric compression (Figure 2) s hould be calculated according to the following conditions:
• Inside:
(twelfth)
s the area of concrete compressive zone, is determined from the condition compressive focus areas coincide with the setpoint of A ib
the external forces.
60
ARN bb •
TCVN 5574: 2012
For structures with rectangular cross section,
Ai b s determined by the formula: 2 0 • • • •1 • • bh A b he • •
•
(13)
For concrete structures under eccentric compression is not allowed to appear cracks under the conditions of use, in addition to the calculation under the conditions (12) to check more conditions (14), taking the work of concrete tensile zone (see 6.1.1, Figure 3):
•
•
WRN bt pl
(14)
• • re
0
For structural condition rectangular section (14) has the form: •
first , 75
•
N
6
0
R bh bt
•
(15)
• •
heh
The calculation of concrete structures under eccentric compression mentioned in 4.1.7b must be done under the conditions (14) and (15)
In the formula from (12) to (15):
• coefficient, determined by the formula (19); •
coefficient, taken as follows:
+
for heavy concrete, concrete granules, lightweight concrete, hollow concrete: ........ 1.00
+
for concrete honeycomb be autoclaved: ........................................ ......... .85
+
for concrete honeycomb is not autoclaved: ....................................... 0.75
W the pl bending moment of cross-section resistance for tensile fibers outermost mention inelastic deformation of concrete in tension, which is determined by the formula (16), assuming no axial force:
2 I b 0
•
pl
• S
xh W
•
b 0
(16)
r i s the distance from the central section of the core section to point away from the tension of all, be determined by the formula:
•
(17)
r • AW
• see 7.1.2.4; Position neutral axis is determined from the condition:
b
•
•S xh
• A
•
0
6.1.2.5 Coefficient values • the effect of the curvature to the eccentricity
bt
(18)
2'
0
e the longitudinal force, defined
according to the formula:
sixty one
TCVN 5574: 2012
•
first
•
(19)
first•
NN cr
Inside cr
N i s tipping conventional forces, is determined by the formula:
cr
•
6 ENb 2
• l l 0I
•0 4 ,11 • • 01 • • • 0 , e •
•
• ,first
(20)
• •
In formula (20):
• l coefficient mention the impact of long-term effects of weight to the curvature of the structures in limit state obtained by:
• • l
• first
but not greater than
first •
l
•
(21)
MM
• ;
Inside:
•
the coefficient depends on the type of concrete, taken from Table 29;
M t orque is taken for tensile or compressive margin less than the cr oss section due to the effect loads of regular, long-term temporary load and short-term temporary load;
M t he same, similar M,b ut due to frequent load and long-term temporary load; l l 0
is determined in accordance with Table 30;
• e
coefficient, degree
0
• e , min • here:
•
heh , but not less than min
0,
• 0 5,
0
f and
:
hl 0• 01 , 01 R b
(22)
R b is calculated by megapascan (MPa).
If the bending moment (or eccentricity) due to the total load and total load due to frequent and long-term temporary load with different
• l
accents, the
taken as follows:
+
when the absolute value of eccentricity by the entire payload 0
+
when the e
0•
: • ,ten hour
• • llfirst•
(10 1
• • l 1 )
0
e > h
,ten : • l • first;
,
heh
Inside:
• l first is determined by the formula (21) with M t aken by force along N ( b y weight frequently, temporary long-term and short-term transient causes) multiplied by the distance from the central section of the edge is pulled or compressed less than both due to load regular and temporary load long-term causes out.
62
TCVN 5574: 2012
Table 29 - Coefficient • i n formula (21) Concrete Type Value of • 1.0
1. Concrete heavy 2. Concrete small particle group:
•
A
1.3
•
B
1.5
•
C
1.0
3. lightweight concrete with:
•
Arti Artifi fici cial al aggr aggreg egat ate e dens dense e type type
1.0
•
artificial porous aggregates
1.5
•
natural aggregates
2.5 2.0
4. Concrete Hollow 5. Concrete honeycomb:
•
autoclaved
1.3
•
not autoclaved
1.5
NOTE: Classification of concrete granules group are specified in 5.1.1.3.
Table 30 - Length of calculation 0
l of concrete structures under compression eccentric
Featured link between walls and columns
Value 0 l
1. bearing above and below a) the title match at both ends
hour
b) when cantilevered and the other end may shift, for the home: •
many beats
1,25H
•
one step
1,50H 2,00H
2. Stand free NOTE: H is the height (or wall) between the floor minus the slab thickness or height freestanding structure.
6.1.2.6 Calculates compressive compressive concrete components locally should be conducted according to 6.2.5.1 and 6.2.5.2.
6.1.3 Profiles bending 6.1.3.1 Flexural concrete elements (Figure 3) should be calculated according to the following conditions:
•
bt
WRMpl•
(23)
Inside:
•
coefficients, taken according to 6.1.2.4;
W d pl etermined by the formula (16), for structures wit h rectangular section W pl pl •
bh
pl et certification: W g
2
(24)
35
63
TCVN 5574: 2012
6.2
Calculation of reinforced concrete structures according to reliability
6.2.1 General Principles 6.2.1.1 Reinforced concrete structures must be c alculated on the section perpendicular to the longitudinal axis tilt-section components and structures to the longitudinal axis in the direction of the most dangerous. When torque required inspection section reliable space is limited by the spiral cracks in the tensile direction most dangerous could happen. happen. Also, it should calculate the structures under the local effect of load (local compression, compression puncture, puncture, tear).
6.2.1.2 When there is no adhesive tensile reinforcement, structural calculations according to reliability conducted under personal guidance.
6.2.2 Calculation under section perpendicular to the longitudinal axis components
6.2.2.1 Critical internal resources on the section perpendicular to determine from the following assumptions:
•
Ignore the possibility of concrete in tension;
•
The ability of the concrete compressive stresses, degree
•
Deformation (stress) in the reinforcement is determined depending depending on the height of the concrete compressive zone and
R, are evenly distributed on the compressible region;
b
considering the deformation (stress) by tensioned (see 6.2.2.19);
•
Tensile stress in the reinforcement is taken not greater than tensile strength calculations
•
Compressive stress in reinforcement is taken not greater than the compressive compressive strength calculationssc
R;
S
R.
6.2.2.2 When external force acting in the plane going through the axis of symmetry of the section and reinforced set focus the edge perpendicular to the plane of that, the calculation section perpendicular to the longitudinal axis structures should be carried out depends on the correlation between the relative value of the height of the concrete compressive
• •
hx , is determined from the corresponding eq uilibrium conditions and relative value of height 0
for concrete compressive zone R
•
(See 6.2.2.3), at the time when the limit state of structures occur
out simultaneously with the stresses in reinforcement tensile strength reaches calculations S the corresponding working conditions, except coefficients
6.2.2.3 Value
R,t aking into account the system
• S (See 6.2.2.4).
6
• R is determined by the formula: •
• R • •
• •
sc sr ,u
(25) • • • 11 •
• • • 1first•
Inside:
• is characteristic of concrete compressive zone, defined by the formula: • • • •
0, 008
R b
here:
•
the coefficient is taken as follows:
+
sixty four
for heavy concrete: .................... .............................. .................... .............. .... ................... ............................. ............. ... 0.85
(26)
TCVN 5574: 2012
+
Concrete for small particles (see 5.1.1.3) Group A: ................................... .. 0.80 Group B and C: ................................. 0.75
+
for lightweight concrete, concrete and hollow concrete honeycomb: ............................ 0.80 For other types of autoclaved concrete (heavy concrete, lightweight concrete, hollow concrete), coefficient • get down 0.05;
R c b alculated megapascan (MPa); •
SR
the stresses in the reinforcement (MPa), for reinforcement:
+
limite lim limited ited d flow flow reality: realit reality: y: CI, CI, CI, AI, CII, CII, CII, A-II, A-II A-II,, CIII, CIII, A-III, A-II A-III, I, A-III A-II A-IIII B, Bp-I: • SR R• •
+
•
;
sp s
limite lim limited ited d flow flow convention: conv convent ention ion:: CIV, CIV, A-IV, A-IV A-IV,, AV, AV, A-VI A-VI and and and A A T- V II: • SR R •
+
S
• 400 • • sp • • •
sp
;
high strength fiber and cable types: B-II, Bp-II, K-7, K-19:
• SR R •
S
• 400 • •
sp
, (then
• • sp • 0 );
here: R t S ensile strength is calculated taking into account the coefficient corresponding working conditions
• si , exce ex except cept pt 6 • • • • a)
b)
sp
sc , u
sp
• S (See 6.2.2.4);
is taken with
• sp •
first ;
see 6.2.2.19; is the limit of the stress in the compressive reinforcement, is taken as follows:
For structures made of heavy concrete, concrete granules, lightweight concrete, depending on the factors mentioned in Table 15:
+
with such such kind of load is applied applied at 2a: ......... ............. ........ ........ ........ ...... 500 MPa
+
the effects effects of load load as in 2b: ....... ........... ........ ........ ........ ....... ... 400 MPa MPa
For structures structures made from concrete and concrete concrete hollow honeycomb, honeycomb, in any case loads are taken taken by 400 MPa. When calculating
•
texture compression stage before value
Value
sc , u
= 330 MPa.
• R is determined by the formula (25) for concrete structures made from honeycomb to be removed is not greater than 0.6.
6.2.2.4 When calculated according to the durability of reinforced concrete structures using high-strength steel reinforced (limited flow convention) CIV
• • • R ,
group, A-IV, AV, A-VI, A T- VII, B-II, K-7 and K-19, while complying with conditions
tensile strength of reinforcement
S
R s hould be multiplied by the coefficient
6
• S (See Section 6 Table 23) was determined
according to the formula:
65
TCVN 5574: 2012
• • S 6 • • • •• • • • • •
•
• • • • •
1•
•
21
• R
(27)
Inside:
•
coefficient, taken to the type of reinforcement group:
+
CIV, A-IV: ................................. 1.20
+
AV, B-II, Bp-II, K-7, K-19: ....... 1.15
+
A A-VI, -VI, A T - VII: ............................. 1.10
For the case of tensile chord, as well as drag eccentric vertical forces placed in the middle due to the synergy of reinforcement, value
• S 6 is taken by •. 0, 9
When solder joints located in the components have reached the bending moment
M max
M ( max
torque is calculated
• S for reinforced CIV group, A-IV, AV taken not greater than 1.1; for reinforcement
the largest), coefficient values 6
A-VI group and A T- V II took no greater than 1.05. Coefficient 6
• S regardless of the structures: -
calculated load loop;
-
arranged reinforced with high strength steel fibers closely spaced (no gaps);
-
used in corrosive environments.
6.2.2.5 For reinforcement in the tension placed under compression, when subjected to external forces or in the period prior compression, compressive
R ( s ee 6.2.2.6, 6.2.2.7, 6.2.2.11, 6.2.2.18) should be
strength calculations sc
replaced by stress coefficient
• sp •
first ,
• •
sc,u
• •
sc,u sp
• • sc• (MPa) but not greater than
R,I nside
sc
sp
•
•
identified with
taken in 6.2.2.3.
A. constructions bending rectangular section, T, letters Ia nd rings
6.2.2.6 For the rectangular section of the bending structure outlined in 6.2.2.2 (Figure 4), when
• •
should be calculated according to the following conditions:
•
b
•
0
•
• • bx xh sc 5 0, AR RM
s
•
0
• ah''•
(28)
in which height compressive zone x is determined from the condition: •
66
RARAR ' •
sc ss
bx
bs
(29)
• hx0 •
R
TCVN 5574: 2012
' a
A ' S
R sc A ' S
x
R b A b
M A b 0
h h A S R S A S
a b Figure 4 - Diagram internal force and stress diagrams on sections perpendicular to the longitudinal axis of reinforced concrete structures in bending when calculated according to reliability
• •
6.2.2.7 The calculation of the winged section located in the compressible when
hx0 • • R should be conducted
depending on the location of the boundary compressive region:
a) If the border areas through the compressive type (Figure 5a), meant to satisfy the condition:
•
RAR hb •' sc ffbss
(30)
AR''s
then the calculation is done as for the rectangular section width b ' f a ccording to 6.2.2.6. b) If the border region abdominal compressive passing beam (Figure 5b), ie not subject to the condition (30), then the calculations performed under conditions: •
b
•
0
•
••
0,
•
bx • AR• 0hhhbb • xh '' 5ffb • R , RM • • 0
'5
sc f
s
•
0
• ah''•
(thirty first)
in which height concrete compressive zone x i s determined from the cond ition:
• Value
'
Rbs bx RARAR • •
•
•
fb
''f • HBB
(32)
b •f u sed in calculations are taken from the conditions: the width of each side, from the edge of the beam is not larger belly 1/6 rhythm
b •f n ot greater than:
structures and take
•
sc ss
when the horizontal ribs or when
hour f • • 0.1 hour : .................. 1/2 distance between the ribs waterway
vertical;
•
when no horizontal rib or when the distance between them is greater than the distance between the longitudinal ribs, hour f • < 0.1 hour : .................................................. ............... 6
•
hour •;
f
when cantilever wing form: +
case f
+
0.05 cases hour • f
+
case f
hour • • 0.1 hour : ...................... 6
f
hour • < 0.1 hour : ......... 3 f
hour •
hour •
hour • < 0.05 hour : ....................n ot to mention wings in the calculation.
sixty seven
TCVN 5574: 2012
a)
b)
b ' f
b ' f
' a
A ' S
a
f ' h '
A ' S
f ' r u o h
x
h x r u o h
0 r u o h
0
a
A S
a
A S
b
b
a - side; b - in the belly Figure 5 - Position the compressible boundary on constructional section
reinforced concrete flexural
• • R hx0 . Case
6.2.2.8 When calculated according to reliable bending structure should follow conditions
if the area of tensile reinforcement structure on request or from calculations according to the second limit state is taken larger than the
• • R hx0 , It is necessary to conduct
reinforcement required to comply with conditions calculated according to the formula for the general case (see 6.2.2.19). If the results calculated from
• • R hx0 , allows calculation under the
the formula (29) or (32) show
events (28) and (31), while the height corresponding compressive region is determined from the formula:
• •
'
•
'
• sc ss
sc ss
•
bs
• RARA
(33)
bx
bs
R bx • RARA•
' fb
' • HBB f
•
(34)
Inside: •
S
0, 2
• 0,
• • 0• 2
• • R •
,
• • 35 • 1 • • • R s • sp
• • • •
RRS
(35)
here • •
hx ( x a re worth 0
R t aking into account the coefficient corresponding working conditions S
of reinforcement);
• sp - is determined by the coefficient sp
•
> 1.0.
For structures made from concrete B30 and lower levels have not stretch reinforced CI group, AI, CII, A-II, CIII, A-III and Bp-I, when
•
•
hx 0• for calculations under conditions (28) and (31), which replaced the value
R
hx 0• .
R
6.2.2.9 For bending structure section rings with radii ratio between internal and external
1
rr • 2
and reinforced the perimeter evenly distributed (ratio of not less than 6), the calculation should be done when calculating compressive eccentric structures in 6.2.2.12. Meanwhile, in the formula (41), (42) taken N = 0 and in formula (40) replaced ne w ith 0 the value of bending moment M.
68
0, 5
TCVN 5574: 2012
B. eccentric compressive structures with rectangular section and rings 6.2.2.10 When calculating reinforced concrete structures under eccentric compression should mention random eccentricity according 02/04/12 original, as well as the influence of the curvature to the bearing capacity of structures under
6.2.2.15. 6.2.2.11 The calculation of compressive structures eccentric rectangular section referred to in 6.2.2.2 should be taken:
a) When
• •
hx
• 0 • R
(Figure 6) under the following conditions:
•
•
b
0
0 AR , 5 bx • •xh R Ne sc s
•
•
0'
• ah' •
(36)
which, under compression zone height is determined by the formula: '
•
• RARARN • sc ss
(37)
bx
bs
N ' a
e
R b
A ' S R sc A ' S
e '
x
R b A b
A b 0
h h A S
R S A S
a b Figure 6 - Map of the internal forces and stresses chart on sections perpendicular to the longitudinal axis reinforced concrete structures under eccentric c ompression when calculated reliability
b) When
• •
hx
•0 • R - also under conditions (36), but height compressive zone is defined as
after:
-
For structures made from concrete or lower level B30, reinforced CI group, AI, CII, A-II, CIII, A-III, x i s determined by the formula: • •
'
•
• RARAN sc ss
(38)
bx
bs
Inside:
•
-
S
• • • • •
•
twelfth
1
/
• • 1• R • •
(39)
0hx
• • R
S
For structures made from concrete B30 larger level as well as for reinforced structures using higher group A-III (non-tensioned or prestressed) - x i s determined according to the formula (66), (67) or (68).
6.2.2.12 For structures under section eccentric compression rings have the ratio of the radius and the outer radius rr1 1 • 0, 5 , evenly distributed reinforced the perimeter (the vertical bars of not less than 6), the calculations should be carried out under the following conditions:
0
• •
Ar•R R AR tot s mb sc,
Ne • s
sine
• • •
•
AR • z ss ss, tot cir
(40)
69
TCVN 5574: 2012
which, relative area of concrete compressive zone is determined from the formula:
••
N • •
•
cir
•
•
b
• •
sp
•
sc
• AR ss
first
•
(41)
, tot
• ARRAR
2
ss
, tot
• cir •
If the results calculated by the formula (41) shows the value
0, 15
, then in the formula (40) value
• cir is determined by the formula:
• cir •
N • ••
•
b
• S
in particular, the value
and S z is
• AR , sss
• •
tot sp
(42)
ARAR sc , tot s
determined according to the formula (43) and (44) with
• cir •
0,15
.
In the formula from (40) to (42):
r m The average value of the inner radius and outer radius of the section; r r S adius circle passing reinforced focus; A
s , tot
the entire area along the reinforced section;
• S coefficient, determined by the formula: •
• •
S
1
(43)
• • 2 • cir
z S is the distance from where the tensile force of the reinforced central section to be determined by r:
formula (44) but did not get bigger S z
•
sp
is identified with coefficients
S
•
•
• sp •
•cir r s
, 0 • twelfth , 3 •
(44)
first ;
• firstcoefficient, determined by the formula: •
first
• •
r
•
•
(45)
sp
R s
here:
• r coefficients, taken for reinforcement: +
limited actual flow (group CI, AI, CII, A-II, CIII, A-III): ................. 1.0
+
limited flow convention convention (CIV group, A-IV, A-IV, AV, A-VI, A-VI, A T- VII, B-II, Bp-II, K-7, K-19): ............................... .............................................. 1.1
NOTE: For other types of steel under Vietnamese standards, see Appendix B.
•
2
is the coefficient, which is determined by the formula:
•
•
• •
(forty six)
twelfth
which values • b e obtained by: • •
R c S alculated megapascan (MPa).
70
• 4
first , • 5 R S 10 6
(47)
TCVN 5574: 2012
• S • 0 , then in the formula (40) replaced
If the results calculated by the formula (43) for value value
• cir
calculated from the formula (41) with
•
• • 1
2
• S • 0
and
• 0 .
6.2.2.13 Structure special section made of heavy concrete, concrete reinforced granules indirectly should be calculated according to the instructions in 6.2.2.11 and 6.2.2.19. Section included in the calculation only the concrete section ef
Al imited by the axis of the outer rebar or wire mesh belt axis of spiral reinforcement (Figure 7). Then
b
R i n the formulas from (36) to (38), (65) and (66) is replaced by R,
intensity prismatic converted
, even when high-intensity fiber reinforced,
R b sc e replaced by
R,
sc red
.
il ef 0 structural reinforcement of the indirect value should not exceed:
slenderness
Inside: ef
red b
i
+
55, when reinforced steel mesh i ndirectly;
+
35, when reinforced with spiral indirectly.
radius of inertia of the section included in the calculation.
a)
b)
S S
A s, cir
A ef A ef
A sx
A s, cir
A sy
h t l a e H
l
l x
d ef
a) steel mesh; b) reinforced twisted form Figure 7 - structures with compressible have indirectly reinforced
Value
R,
red b
is determined according to the following formula:
a) When is indirectly reinforced steel mesh,
R,
red b
is calculated as follows:
•
b,
Inside,
R,
xy s
• •S • RRR xy b red , xy
(48)
is the intensity of sound calculation in steel mesh;
•
•
A • nl A n
yx x sx sy y
l xy
(49)
A s ef
71
TCVN 5574: 2012
here:
n,x sx A A x l
are respectively the bar, cross sectional area and length of the mesh bar steel (in the distance between the axis of the outer reinforcing bars) in a way;
n,Health A Health l sy A
is similar, but in the other;
A ef
is the area of concrete within the steel mesh;
S
is the distance between the mesh;
•
coefficient mention the influence of indirect reinforcement, which is determined by the formula: first
• •
0, 23
•
with
•
(50)
• •
R xy s , xy
•
(51)
R b • ten
R, s xy , R c b alculated megapascan (MPa). For concrete structures made from smaller particles, coefficient • t ake no greater than 1.0. Sectional area of the rod in welded steel mesh on a unit length of this method or other methods can not differ more than 1.5 times.
b) When indirectly reinforced with spiral or ring,
R b , red is calculated using the formula:
, red b
•
1 •2 • • • •
• RRR , s cir
•
cir b
75
0
de ef
• • • •
(52)
Inside: e 0
is the eccentricity of axial force (excluding the effects of curvature);
R s , cir is the core strength of twisted calculation;
• cir
is the reinforcement content, obtained by:
• cir •
4 A
, cir s
(53)
sd ef
here:
A
is the cross-sectional area of the twisted core;
cir s
d ef
diameter core section in torsion;
S
the twisting step.
Reinforced content value is determined according to the formula (49) and (53), for concrete structures made of small particles is not greater than 0.04 taken. Compressive strength calculated conversion
R,
sc red
reinforcement of high intensity along CIV group, A-IV, AV, A-VI
and A T- V II, for structures made of reinforced concrete with heavy weld mesh indirectly be determined by the formula (54):
72
TCVN 5574: 2012
sc , red
• RR sc
2
•• first• • first • • • •• •
s
• • • •
• • first
•
• •
• sc s first• • first • • • sc • RRRR
(54)
• • first • •
R.
but get no bigger S In formula (54):
E 5 S •• •
8,
• • first
R S • 10
(55)
3
Inside:
• •
0,
• •
,
8
tot's ef
RAA • b • • • • 100 1 • •
here:
•
A
coefficient, taken as follows:
tot's
A ef R b
+
CIV reinforced for the group, A-IV: ............. .... 10
+
for reinforcement reinforcement group AV, A-VI, A-VI, A T- VII: ..... 25
the entire cross-section area of the bars along the high intensity; is as in the formula (49); is calculated by megapascan (MPa).
Value • t ake not less than 1.0 and not more than: +
Reinforced with CIV group, A-IV: ....................... 1.2
+
Reinforced with groups AV, A-VI, A T- VII ............ 1.6.
When determining the limit values of the relative height compressive zone on section reinforced indirectly by the formula (25), then the value • w hich is taken by the formula: • • • •
0, 008
R b • • 2 •
(56)
0, 9
Inside:
•
coefficients, taken according to 6.2.2.3;
• 2 coefficient, degree •
ten ,b ut not greater than 0.15; •
here, • is the reinforcement content xy
or cir
•
is determined by the formula (49) and
(53) corresponding to a grid of reinforced steel or indirectly twist ed.
Value
•
sc,u
in formula (25) for components with high strength reinforcement obtained by:
•
sc,u
• •
• 2 8 • • • 5E S • 10
• 3
(57)
but not more than:
seventy three
TCVN 5574: 2012
•
900 MPa for reinforced CIV group, A-IV;
•
1200 MPa for for the group group reinforced AV, A-VI, A T- VII.
When considering the influence of the curvature to the bearing capacity of reinforced structures placed indirectly, use the instructions in 6.2.2.15 when determining the moment of inertia of the cross section bounded by the bars of the grid steel or components within belt twisting. Value
N c cr alculated from the formula (58) must
multiplied by the coefficient
• • first
0,
•0 25,
l 0 c ef 05•
10 (here:
c i ef n height or diameter of the part more
• e ,
Concrete area included in the calculation), and when determining min
Formula (22) is replaced by
0, 01
•
0
cl ef
• • 2 , with •
2
•
0, first • l 0
, the second term in the right hand side of
c ef • •
• 1 1, 0 .
Reinforced indirectly included in the calculation condition when the bearing capacity of the structures determined by the instructions in this (with
R,
A aef nd
red b
) exceeded its bearing capacity but
determined under section Natural A and intensity values of concrete calculations
R n b ot to mention photos
Indirect effects of reinforcement. In addition, indirect reinforcement needed to satisfy the requirements under 8.7.3 structure. 6.2.2.14 When calculating compressive structures with reinforced eccentric indirectly, besides calculating reliability according to 6.2.2.13 should be calculated against cracking for concrete protection layer.
The calculation is done according to the instructions given by the values 6.2.2.11 and 6.2.2.19 using computational load (
•
f
R,
= 1.0) with the whole area of the concrete section and calculate the intensity degree
ser b
and
R,
ser s
for the second limit state, the compressive strength of reinforced calculate earned value R,
ser s
but not greater than 400 MPa.
When determining the limit values of the relative height of the compressibility of the formulas (25) and (69), taking •
sc,u
= 400 MPa, and in the formula (26) replaced with 0.006 coefficient of 0.008.
When considering the impact of the pieces need to follow the instructions in 6.2.2.15, which
formula (22) but rather 0.01 b
R b y 0.008
R,
e
•
been identified
.
ser b
6.2.2.15 When calculating compressive eccentric component, consider the effect of the curvature to the bearing capacity of the structures by calculating structural deformation in the diagram (see 4.2.6).
Allow structural calculations in the diagram does not deform if the effect of the curvature (when the piece be determined by by the the condition (36), (40), (65), by by multiplying 0 il • 14 ) the durability, be
e c oefficient •.
Meanwhile tipping conventional forces in the formula (19) to calculate • b e obtained by:
cr
•
6 l EN 2 0
Inside:
74
l 0
taken according to 6.2.2.16;
• e
coefficients, taken according to 6.1.2.5;
• • • • • I 0• 4 ,11 • • 0 1 • • lb • 0 , • •• • • pe • •
• • • • • ,first • • I S • • • •• • • •
(58)
TCVN 5574: 2012
• l
is the coefficient, which is determined by the formula (21), in which the torque MT a re determined to
with axes parallel to the border areas and passing compressible core tensile rebars most or focus the bars under compression at least (when the entire section is compressed). M d ue to the effect of causing the entire load, T d ue to the frequent load and long-term temporary load caused. If the torque (or eccentricity) on different marks, should follow the instructions in 6.1.2.5.
•
p
the coefficient at the effects of tensile reinforcement to the stiffness of the component. When compression forces before
•
are evenly distributed on the section,
• p •
p
• 12 1
determined by the formula:
• bp
0
(59)
R b he
here:
•
• sp •
bp is determined by the coefficient
first ,0
;
R b b e taken without regard to the conditions of employment coefficient of concrete; value heh take
0
• •
no greater than 1.5;
EE bs
For concrete structures made of small particles of Group B, in the formula (58) value of 6.4 is replaced by 5.6. When calculating the effect of bending moments outside the plane, the eccentricity of axial force 0
e i s taken by
random eccentricity (see 4.2.12). l o f reinforced concrete structures under eccentric compression so determined as to
6.2.2.16 Length calculation 0
with components of the frame structure may include state deformation of it when the load placed at the most unfavorable for structures, taking into account the deformed inelastic material and the presence of cracks on structures.
For the structural components common, lets get the length calculation 0
l o f structures such
after:
a)
For the multi-storey columns have the rhythm of not less than two, the link between the beams and columns are assumed to be hard when the floor structure
is:
+
build:
+
monolithic pour:
0
• H l; 0•
0, 7 H l
,
here hour t he floor height (distance between the center of the button);
b)
For the column a link layer bearing structures match the roof (the roof structural system is considered hard in its plane, capable
of transmitting horizontal forces), as well as the pillars of the viaduct: 0
l
taken under
Table 31.
c)
For structures of truss and arch: 0
l
taken from Table 32.
75
TCVN 5574: 2012
Table 31 - Length of calculation 0
l o f t he one-story column
Value 0 l w hen calculated in the horizontal plane frame or perpendicular to the axis
horizontal or perpendicular to
Featured
the frame parallel with the viaduct when
viaduct have
no
the bracing in the plane of the row of upright or pillow anchor
when mention
Section under crane beams
loads by crane
column
Section on crane beams
incoherent
1.5 firsthour
0.8 firsthour
1.2 firsthour
continuity
1.2 firsthour
0.8 firsthour
0.8 firsthour
incoherent
2.0 2 hour
1.5 2 hour
2.0 2 hour
continuity
2.0 2 hour
1.5 2 hour
1.5 2 hour
one step
1.5 hour
0.8 firsthour
1.2 hour
many beats
1.2 hour
0.8 firsthour
1.2 hour
incoherent
2.5 2 hour
1.5 2 hour
2.0 2 hour
continuity
2.0 2 hour
1.5 2 hour
1.5 2 hour
one step
1.5 hour
0.8 hour
1.2 hour
many beats
1.2 hour
0.8 hour
1.2 hour
2.5 2 hour
2.0 2 hour
2.5 2 hour
one step
1.5 hour
0.8 hour
1.2 hour
many beats
1.2 hour
0.8 hour
1.2 hour
incoherent
2.0 firsthour
0.8 firsthour
1.5 firsthour
continuity
1.5 firsthour
0.8 firsthour
1.0 firsthour
joint
2.0 hour
1.0 hour
2.0 hour
hard
1.5 hour
0.7 hour
1.5 hour
column
House with crane
While not
Section under crane beams
mention the
column
load of crane Section on crane beams column
Career column
Column section below
House no cranes Section column on
column with constant section
when the crane beams
viaduct While the link between pipelines and rhythm support column
NOTE 1:
hour the entire height of the column from the surface on the nail to the horizontal structure (rafter or truss beam oblique bar rafter) in the corresponding plane; t he column section below the hour first
height (from the surface on the underside of the nail to the crane beams).
is the height above the column section (from the top of the column to the structural level in the horizontal plane, respectively). NOTE 2: If the link to the top of the hour 2 column with indoor cranes, column height calculation section on the plane containing the vertical axis degree columns 2
HOUR .
76
TCVN 5574: 2012
l constructional and arch truss
Table 32 - Length of calculation 0
Structures of
Length calculation
l 0constructional and arch truss
a) Bar on the wings when calculated in present
flat rig
••
81 • heh ten
0.9 l
••
• heh 81 ten
0.8 l
for the lower skylight, the skylight width greater or equal to 12 m outside the
1. The components
0.8 l
plane truss
of the rig
In the remaining cases
b) ADD oblique and
in the plane of the gantry
0.9 l
0.8 l
vertical bar when outside the
calculating
0.9 l
0.9 l
0.8 l
0.8 l
plane of the gantry
2. Arch
when calculated in
3 matches
.580 L
2 matches
.540 L
the plane arch
mismatched While arch-plane properties (any)
.365 L
L
NOTE:
l i s calculated according to the length components of the center button; also for wing bar on the rig when calculated in the plane of the truss, l is the distance between the nodes link them;
L is the arch length along the axis of its geometry; when calculated beyond the arch plane,
L is the distance between the link point it in a direction perpendicular to the
plane of the arch;
hour the depth of the bar on the side of the rig; first b 2first b i s the width of the bar cross section respectively on the wing and vertical bar (bar oblique) of the gantry. C. tensile structures with chord 6.2.2.17 When calculating the cross section reinforced concrete structure tensile chord must comply with the following conditions:
• Inside:
A
tot's
ARN , tot
ss
(60)
is the cross-sectional area of the entire reinforced along.
D. eccentric tensile structures with rectangular section
6.2.2.18 Calculating section eccentric tensile structures outlined in 6.2.2.2 should be conducted depending on its placement along N:
a) If the vertical force N p laced in between the forces of the reinforcement S and S • ( F igure 8a): calculated according to the following conditions:
'
•
AR Ne • 0 ' • ah' • ss
(sixty one)
•
Ness •
(62)
0
• AR' • ah
77
TCVN 5574: 2012
b) If the vertical force N outdoor installation spacing in reinforced synergy S a nd S • ( Figure 8b): calculated according to the following conditions:
•
b
•
0
•
0 AR , 5 bx • •xh R Ne sc s
•
0'
• ah' •
(63)
including: height compressive zone x i s determined by the formula: •
'
sc ss
• • RNARAR s
b
bx
(sixty four)
• • R hx0 , then in the formula (63) replaced
If the formula (64) calculate the value
• • R hx0 , with
• R
be determined according to 6.2.2.3.
a)
' a
A ' S
R S A ' S
' e 0
h h
N
A S
e
R S A S
a b b)
' a
A ' S
R b R sc A ' S
R b A b
x
A b 0
h h
' e
A S R S A S
e
a
b
N a - axial
b - axial
N placed between the forces of reinforced S, S •;
N o utdoor installation spacing of reinforcement forces S, S •
Figure 8 - Diagram internal force and stress diagrams on sections perpendicular to the longitudinal axis of reinforced concrete structures tensile eccentricity, as calculated under section reliability
E. Case extensive calculations (With section, external force and reinforcement layout any) 6.2.2.19 The calculation of the cross section in the general case (Figure 9) should be conducted from the condition:
• • •
bb
•
•
• • SSRM si si
(65)
including: the "public" before the parentheses are taken with the case bearing structures eccentric compression and bending, the "minus" is taken for the case of tensile structures.
78
TCVN 5574: 2012
I
2
8
4
0 r u o h r 6 u 0 o r 5 0 u h r o u h o h
0 r u o h
0 3 r 0 u r o u h o h
R b
1
0 r u o h
• s1 A s1 • s2 A s2
first
2
• s3 A s3
x
3
7 0
8
R b A b
A
• s8 A s8 • s4 A s4
4 B
• s7 A s7 • s6 A s6 • s5 A s5
6 7 5
I
C
II the plane parallel to the plane of the effect of the bending moment, or plane passing along and force set point of the internal case of traction, compression; A synergy is placed in compression reinforcement and concrete in compressive zone; B is a set of forces in reinforced tension; C is located outside force
Figure 9 - Diagram internal force and stress diagrams on sections perpendicular to the longitudinal axis
reinforced concrete structure in the general case calculation section according to reliable
In formula (65):
M i s the bending structure: the projection of external force torque due to the square plane angle with the straight line compressive limit of section; is in compressive structures and pull eccentricity: the torque due to vertical force N f or axial straight line parallel to the compressive limit and go through:
+
focus section of the bars along the tensile or compressive most at least when the compressive eccentric structures;
+
point compressive zone, far away from the limit line when the compressive than tensile structures eccentricity;
S b
the static torque of the cross-sectional area of concrete compressive zone for the corresponding axis in the above-mentioned axis. Meanwhile in the bending structure of the shaft position is taken as i n the case of eccentric compressive components;
S si
the static torque of rebar area along th i f or the corresponding axis in the shaft above;
•
the stresses in the bars along th i i s determined according to the instructions in this article.
si
Height compressive zone x a nd stress
•
si
determined from solving simultaneous equations:
bb
•
•
•
si si
• Naar • 0
(66)
79
TCVN 5574: 2012
• si •
•
,
•
•
sc
• • • • • 1 • • • spi • • • • iu •
(sixty seven)
11 ,1
In equation (66) the "minus" before value N t aken for eccentric compressive components, the "plus" get to pull eccentric structures.
Additionally, to locate the zone boundary compressive bending oblique must comply with additional conditions on the parallel plane the effect of the torque caused by internal and external forces, even when squeezed or pulled eccentric oblique must comply to additional conditions: the setpoint of the external force acting axially, of the compressive force in the concrete and reinforcement compression, and of forces in reinforced in tension (or external force acting along the axis, where the compression force in concrete and in full synergy reinforcement) must lie on a straight line (Figure 9). If the value
•
si
calculated using the formula (67) for reinforcement CIV group, A-IV, AV, A-VI, A T- VII, B-II, Bp-II, K-7
• R si , the stress
and K-19 exceeded
•
•
si
si
is determined by the formula:
• • • • • • •first• • • • •
•eli • i • • R Ri •si eli • •
R r egardless coefficient
Stress cases found by the formula (68) exceeded si
•
Formula (65), (66) the value coefficient 6•
be replaced by si
• S , In the
6
R t aking into account the coefficient corresponding working conditions, including
(See 6.2.2.4).
S
•
stresses
si
(68)
si
enclosed mark is calculated according to the formula (67) and (68), when taken into account to comply
under the following conditions:
R • si •
-
In any case si
-
For pre-stressed structures prestressed spi
•
•
•
•
R; sci si
> •
•
reduced quantities
sci
sc , u
, here
•
sci
the stresses in reinforcement, by
(See 6.2.2.3 and 6.2.2.13).
In the formula from (66) to (68):
A si
is the cross-sectional area along the second rebar i;
•
is tensioned in bars along th i,t aking into account the coefficient sp
spi
•
, Defined
depending on the location of the rebar;
• i
the relative height of the concrete compressive zone,
• •
, Inside hx 0I i
0I
hour i s about
Distance from central axis across t he second section reinforcing bar i a nd a straight line parallel to the compressive limit to the farthest point of the compressive zone (Figure 9);
•
is characteristic concrete compressive zone, defined by the formula (26) or (56);
• Ri , • eli
the relative height compressive zone corresponding to t he time when the stress in reinforcement reach the corresponding
values are si
80
R and
• R si ; value Ri •
and eli •
is determined by the formula:
TCVN 5574: 2012
•
( eli ) Ri
•
•
•
•
, eli ( Ri's )
•
sc ,u
(69) • • • • • • 11 1first • •
here: when
determining si
• : • S, Ri = R
when identified eli
•
• Value
• • spi -
sc,u
: •
S, eli
si
• 400 • • spi • • • spi , • S, Ri calculated megapascan (MPa);
= • R • • si
, •
spi
S, eli
calculated megapascan (MPa);
- 6.2.2.3 and 6.2.2.13 view.
and coefficients • a re defined as follows:
When the the cause cause for for the the kind prestressed reinforced CIV group, A-IV, AV, A-VI, A T- V II by mechanical methods, as well as auto-thermal method or methods of thermal engine automatically, calculated using the formula:
•
• • spi •
• •
spi
•1200 1500• 0
(70)
• 0 4, 8
(71)
R si • 0,
spi
0• 5
,
R si
-
When the the cause cause for for the the kind prestressed reinforced CIV group, A-IV, AV, A-VI, A T- V II by other methods, as well as cause for prestressed reinforced B-II group, Bp-II, K-7 and K-19 by any means, get value
• • In the formula (70), (71), 6 coefficient sp •
•
spi
spi = 0 and coefficients • = 0.8.
taken have included the loss referred to in paragraph 3 and 5 of the Table
<1.0.
Note: Index i t he number of the bars in question.
6.2.3 Calculation of the vertical cross section tilted structures 6.2.3.1 Calculation of reinforced concrete structures under section inclined should be taken to ensure reliability when subject to the effect of:
-
Shear forces on the strip between the cracks oblique tilt (see 6.2.3.2);
-
Shear stress cracks on skewers (see 6.2.3.3 to 6.2.3.5);
-
Shear forces on the strip between inclined compressive load placements and pillows (for short coil of columns, see 6.2.3.6);
-
Bending moment on the cracks oblique (see 6.2.3.7).
6.2.3.2 Reinforced concrete structures subjected to shear should be calculated to ensure reliability on the strip between the cracks oblique tilt condition: Q •
Coefficient
• w first,
0, 3 •
•
11
R bh bbw
0
(72)
consider the influence of belt reinforced with longitudinal axis perpendicular structures, be determined in accordance
recipe: 81
TCVN 5574: 2012
•
w first
•
•1 5 • • w
(seventy three)
but not greater than 1.3, Inside:
• •
Coefficient first • b
WBS
,
• • AEE
sw
bs
is determined by the formula: • b
first
•
first •
• R b
(74)
Inside:
•
coefficient, taken as follows:
+
for heavy concrete, concrete granules, concrete honeycomb: ............ 0.01
+
for lightweight concrete: ............................................ ..................... 0.02
R cb alculated megapascan (MPa). 6.2.3.3 For reinforced concrete structures reinforced with horizontal (Figure 10) shear, to ensure durability oblique cracks need to calculate the most dangerous section tilted condition: •
•
• qqqq , inc s
(75)
sw b
Power cut Q i n formula (75) is determined from external forces placed on one side of the inclined section in question.
Q b
S
S
S
S
S
S
R sw A sw R sw A sw R sw A s, inc
R sw A sw
c 0
c
Figure 10 - Diagram internal force on cross section inclined to the longitudinal axis components
reinforced concrete when calculating shear strength
Power cut
Q ob wn by reinforced concrete, which is determined by the formula:
Q
•
• bb 2 first • • • • • nf •
R bh
bt
2 0
c
Inside c t he length of the projection of the most dangerous sections inclined to vertical structures. Coefficient
• b 2 considering the influence of the concrete is taken as follows: 82
For heavy concrete and concrete honeycomb: .................................. 2.0
(76)
TCVN 5574: 2012
-
For concrete granules: ........................................... ............... 1.7
-
For lightweight concrete with marking according to the average density:
+
• D 1900 ............................................... ........................... 1.90
+
• D 1800: using fine aggregate characteristics: ...................................... 1, 75 fine aggregate used hollow: ...................................... 1.50
Coefficient
•
considering the influence of the compressive side of the T-section, I-beams is determined according to the formula:
f
• f •
0, 75
•
' f
'
• HBB f
•
(77)
hb 0
but not greater than 0.5. In formula (77),
b •f
•
take no bigger
3 hb•f
,
simultaneous horizontal reinforcement should be anchored to
wing.
• Coefficient n
, consider the influence of axial force, which is determined as follows: -
the vertical compression strength, determined according to the formula:
N
• n •
(78)
0,first
R bh bt
0
but not greater than 0.5. For pre-stressed structures, in the formula (78) replaced N b y compressive forces advance P; b eneficial effect of axial compressive force will not be taken into account if t he axial compressive force induced bending moments and torque by point with the effect of lateral loads caused.
-
when subjected to axial traction, determined by the formula:
•
n
•
•
N
0, 2
R bh bt
(79) 0
but the absolute value is not greater than 0.8.
Value
•
• first
•
• •
nf
•
in any case not be greater than 1.5.
Value
Q cb alculated using the formula (76) took no less than
Coefficient
• b 3
•
• • •
3 first
• bt• NFB R
•
bh 0
.
taken as follows:
-
For heavy co ncrete and concrete honeycomb: .................................. 0.6
-
For concrete granules: ........................................... ................ 0.5
-
For lightweight concrete with marking according to the average density:
+
• D 1900: .............................................. ...................... 0.5
+
• D 1800: .............................................. ...................... 0.4
83
TCVN 5574: 2012
For reinforced concrete structure with horizontal reinforcement should also ensure durability under section tilted in between the belt reinforcement, between the knee and oblique reinforcement, r einforcement between oblique together. Power cut
Q,
Q a sw nd
inc s
is determined by the total projection of the internal forces tipping respectively in aggregate
steel reinforced belt and cracks oblique oblique cut through dangerous on the axis perpendicular to the longitudinal axis structures. Length 0
•
blique projection of dangerous cracks on vertical structures are determined from the minimum conditions of expression c o
• take no bigger
• . In the formula for determining b • QQQ , inc s
2a hour nd t the same time 0 not greater than the value c,a
c n ot less than
0
c,v alue
Q r eplacement value c e qual 0
sw b
2 ihour f 0
c
0
. • hc 0
For only reinforced structures perpendicular to the longitudinal axis belt components, with constant step between inclined section under
c
Inside:
•
c w ith minima of expression
consideration, value 0
•
•
0
•first• •
b 2
b
• • fn •
R bh bt
QQ sw • • determined by the formula:
2
(80)
0
q sw
q sw is the internal forces in reinforced belt per unit length components, determined by the formula:
sw
For such structures, shear
•
sw sw
(81)
AR s q
Q i s determined by the formula: sw (82)
Q sw• o cqsw Meanwhile, reinforced belt determined by the calculation shall meet the following conditions:
q
sw
•
• b 3 • • 1•
• • fn •
Rb
bt
(83)
2
In addition, reinforced straps should meet the requirements in 8.7.5 to 8.7.7. When calculating the structural reinforcement along the CIV group of steel, A-IV, A-III B o r reinforcement group AV, A-VI, A TVII (combination), the coefficients
• b 2 , • b 3 as 4
• b
(6.2.3.4) should be multiplied by 0.8.
6.2.3.4 For reinforced concrete structures without reinforcement belt shear, to ensure reliability on oblique cracks need to calculate the most dangerous oblique fracture under conditions:
Q
•
• b
4
• • • first
• n
2
bt
R hb0
(84)
c Among them: the right side of formula (84) took no bigger Coefficient
• b 4
2, 5 R b bh
taken as follows:
•
For heavy concrete, concrete honeycomb: ....................................... ......... 1.5
•
For concrete granules: ........................................... .......................... 1.2
•
For lightweight concrete with marking according to the average density:
+ 84
0
• D1900: ................................................ ...................... 1.2
and not less than
• b first • • • R • bt n bh 3
0
.
TCVN 5574: 2012
+
• b 3
Coefficients
• D1800: ................................................ ..................... 1.0
and n •
as well as value Q a nd c i n formula (84) is determined according to 6.2.3.3.
If the region is considered the effect of shear forces no cr acks perpendicular to the longitudinal axis, ie if meeting the conditions (127) when replacing
conditions (144) by replacing
R,
bt ser
R,
bt ser
and
R,
equal bt R, allows increased reliability component as calculated from ser b
corresponding with bt
R a nd
b
R.
6.2.3.5 The reinforced concrete structure with compressible boundary lie (Figure 11) shear, to ensure reliability in the section inclined to follow 6.2.3.3 and 6.2.3.4 calculations. In particular, working height within the inclined section under consideration is taken as follows
•
For structures with horizontal reinforcement: value 0
•
For structures without transverse reinforcement: value 0
hour b iggest;
hour medium.
0 r u o h
c
Figure 11 - Diagram calculation of reinforced concrete beams with compressible boundary lie
•
6.2.3.6 For short coil reinforced concrete (
0, 9 hl0 ,
Figure 12) shear, to ensure reliability
on the strip between inclined compressive load is applied and the knee, should be calculated according to the following conditions:
0,
• bl •2
8
RQbbwsine •
35
including: the right hand side of equation (85) takes no larger than
(85)
bh 0R and no less than the right side of the expression
bt
(84); • i s the angle between the compressible strip with horizontal calculations. The width of the strip
l i s determined by the formula:
inclined compressive b
b
Inside: sup l
•
llsup
sine
•
(eighty six)
is the length of the transmission along the length of the coil themselves.
When determining the length sup
l
need to consider the important transmission characteristics according to the schemes of different pillows
Structure to cantilever (beam or girder buckling free titles, placed along the cantilever, or perpendicular to the cantilever, etc ..)
85
TCVN 5574: 2012
Q
l l sup
0 r u o h
l b
r u o h
•
Figure 12 - Diagram cantilever calculate short
Coefficient• w2
, consider the influence of reinforced belt placed under the cantilever height, determined by the formula: • w2 •
Inside:
• •
; • AEE• first
w WBS
15 • • • w1
(eighty seven)
; bs
sw
A sw
is the cross-sectional area of the reinforcement belt in the same plane;
S w
is the distance between the belt reinforcement, in a direction perpendicular to them.
When it is necessary to mention the horizontal belt reinforcement and reinforced belt at an angle no greater than 45 o
from horizontal. The horizontal layout of the cantilever reinforced short to satisfy the requirements of 8.7.9. 6.2.3.7 The reinforced concrete structures subject to bending moment (Figure 13), to ensure reliability in the section should be calculated tilt with tilt dangerous section under the following conditions:
•
•
sw s
• MMMM , inc s
(88)
torque M i n formula (88) is determined from external forces placed on one side of the section under consideration for tilting the axis perpendicular to the plane of the effects of torque and passing the setpoint forces b
N in
compressive zone. Of torque
M,S
nd M a sw
M s , inc the sum of the torque to the shaft above the internal forces due to relative
applications in vertical reinforced, reinforced belt, reinforced oblique cut the tension of the tilt section. When determining the internal forces in reinforced cutting through the section inclined, should pay attention to the degree of reinforcement anchored into the outer inclined section.
Height of the compressible section tilt is determined from equilibrium conditions of the internal force projection in the compressive concrete and reinforcement in cut the tension of longitudinal section tilt up structures.
eighty six
TCVN 5574: 2012
z S, inc
S
S
N b
S R sw A sw
S
z
R sw A sw
R sw A S, inc
R sw A sw
R S A S
z sw z sw z sw
c
Figure 13 - Diagram internal force on cross section inclined to the longitudinal axis components reinforced concrete when calculated according to the bending moment resistant durability
Section tilted subjected to torque should be calculated at the cutting position or bending down, as well as at the close of the beam and bearing at the top of the cantilever free. In addition, the inclined section subjected to torque was calculated at positions sudden change the shape of structures (cut part section, etc ..).
M b S e reinforced by vertical cut through the tension
At positions near the bearin g points of components, torque
the inclined section is defined by the formula: (89)
ARM z • ssss
Inside:
A S
is the reinforcement area along the inclined section cut through;
z S
is the distance from the synergy of vertical reinforcement to compressive forces in the region.
If the longitudinal reinforcement is not anchored, calculated tensile strength
ur positioned cut through more R O
S
reduced presence tilted taken under section 5 Table 23. For structures made of honeycomb concrete, reinforced the internal forces in the vertical is determined according to the calculation only when considering the work of the cross in the proximal anchor pillow. torque
sw re borne by the belt reinforcement perpendicular to the longitudinal axis components, with constant step in the tensile range M a of tilt section in question, which is determined by the formula: cq
M
sw
•
sw
2
(90)
2
Inside: q sw is the internal forces in reinforced belt per unit length components, determined by the formula (81);
c
the projection length of the most dangerous sections inclined to vertical structures.
6.2.4 Calculation according to reliable space section ( bending structure twisting simultaneously) 6.2.4.1 When calculating the space section, the internal forces are determined based on the following assumptions: eighty seven
TCVN 5574: 2012
•
Ignore the possibility of concrete in tension;
•
Compressive zone of section space is considered to be flat, situated at an angle • t o the longitudinal axis structures and compression
resistance of the concrete degree
•
2
R b sine
• ,
evenly distributed across the region under compression;
Tensile stress in the reinforced vertical and horizontal rebar cut the tension of the space section in question obtained a R and
calculated intensity S •
sw
R; R f or no tension reinforcement; for
Stress of of reinforcement in in the the compressive degree sc
with reinforced strain obtained in 6.2.2.5.
Structures with rectangular section 6.2.4.2 When calculating the bending structure twisted simultaneously, need to follow the f ollowing conditions:
t
•
hbb 0,first
2
(91)
RM
Inside: b, h r espectively the smaller and larger cross section. Value
R f b or higher grade B30 concrete is taken as for concrete B30 levels. 6.2.4.3 Calculated in accordance with section space endurance (Figure 14) must comply with the following conditions:
•
• • wsst• • first ARM • q • • •
2
•
0
•
0, 5
(92)
xh •
c
b
x M T r u o h
R S A S
a R sw A sw
Q
S
Figure 14 - Map of the internal forces in the space section of reinforced concrete structures bending and twisting when calculated according to reliability
Height compressive zone x i s determined from the condition:
•
• • RARAR
sc ss
bx
bs
The calculation should be carried out with the 3-position diagram of the compressive space section:
88
-
Diagram 1: side compression bending of structures (Figure 15a);
-
Diagram 2: at the edge of structures, parallel to the plane of the effect of the bending moment (Figure 15b);
-
Figure 3: side being pulled by the bending of structures (Figure 15c)
(93)
TCVN 5574: 2012
In the formulas (92) and (93):
A S A • i s the reinforcement area along section located in the tensile and compressive regions corresponding to S each calculation diagrams;
b, h t he size of the edge components, respectively parallel and perpendicular to the World term compressive region:
(ninety four)
• • 2
• BHB
(95)
• • bc
Inside: c t he projection length of the compressible boundary on the longitudinal axis components, the calculation is done with the value c T he most dangerous, c w as determined by calculation methods taken up properly and not greater than
bh) •.
(2
x A ' S
A S
A S
a x 0 r u o h
r u o h
b
A ' S
0
h h
x
a a
A S
b
hh 0
A ' S
b
a - side is compressed by bending; b - side parallel to the plane the effect of bending moments; c - next to being pulled by bending
Figure 15 - Map location of the compressive space section
In formula (92) values • a nd q
•
characterize the relationship between the internal forces
M, t M,a nd Q t aken
as follows:
-
when no bending moments:
-
when calculated by:
+
Figure 1:
• • MM t
+
+
diagram 2:
Scheme 3:
; first
; • q • first
• • 0 ; • q •
• • • MM t
Torque
• • 0 ; • q •
Qh
1• 2M
t
; • q • first
t ending moments M a nd shear Q t aken in cross section perpendicular to the longitudinal axis components M,b
and passing through the focus of the compressive space section.
89
TCVN 5574: 2012
Coefficient values w
•
, characterize the relationship between the horizontal reinforcement and reinforced along, be determined by the
formula:
•
sw w
•
AR sw
(96)
AR sb ss
Inside:
A sw sectional area is a belt reinforcing bars next to the tension of calculating diagrams are reviewed;
S
is the distance between the aforementioned belt reinforcement.
Meanwhile the value w •
take not less than 0, 5
• w , min •
•
(97)
2/1 • MM uw
and not greater than
•
• 15 first , of
• w , max •
• •
•
• • • MM u •
(98)
Inside:
M i s the bending moment, to diagram 2 degree 0; for chart 3 taken with a "-"; M i s u the largest bending moments which cross section perpendicular to the longitudinal axis components to withstand.
If the value
w
•
•
calculated from the formula (96) is less than
(92), (93) is reduced according to the ratio
•
•
, min ww
w , min
, resources The value of internal
AR f ormulated
ss
.
If they meet the following conditions:
M t
•
0, 5 qb
(99)
then the calculation according to the diagram 2 shall comply with the following conditions:
•
•sw
•
b MQQQ
3
t
(100)
b
In formula (99), (100):
b Q,sw
the width of the edge sections perpendicular to the plane of bending; Q i sb to be determined according to 6.2.3.3.
6.2.5 Calculation of reinforced concrete structures subjected to local loads A. Calculating local compressive 6.2.5.1 Calculate local compressive structures (laminated sur face) without transverse reinforcement should satisfy the condition:
• •
90
ARN 1
loc , loc b
(101)
TCVN 5574: 2012
Inside: N
the vertical compression force due to local loads;
A loc
is compressible local area (Figure 16);
first
•
coefficients, depending on the characteristics of the load distribution on the area was localized compression surface, taken as follows:
+
when the load distributed evenly: ........................................... ............. 1.0;
+
when the load is un evenly distributed (below the beams, purlins, lintel) for heavy concrete, concrete granules, lightweight concrete: ...... 0.75 for concrete honeycomb: .................................................. . 0.50
R,
is calculated compressive strength of concrete local, determined by the formula:
b loc
, b loc
here:
• • b •
• • • RR bb
(102)
first;
+
• = 1 for the lower grade concrete B25;
+
• • 13 ,5
bt
for concrete B25 and higher levels;
RR b +
• b •
3
/ 2 AA loc loc 1
but not greater than the following values:
+
when the force diagram according to Figure 16a book, c, d, e, h: for heavy concrete,
concrete granules, lightweight concrete:
higher levels B7,5: ........................................... .................................... 2.5 grade B3,5; B5; B7,5: .............................................. ................................ 1.5 for lightweight concrete and concrete honeyco mb has granted B2,5 and lower: ................... 1.2
+ R,b
when the force diagram according to Figure 16b set, d, g does not depend on the type and grade of concrete: 1.0
R t bt aken as for concrete structures (see item 7 Table 15);
A filter2
is compressible local area calculation determined as directed in 6.2.5.2.
6.2.5.2 Area calculation
A including the area of symmetry through the area being pressed (Figure 16). when the filter2
then, need to follow the following principles:
-
When local load acting on the entire width b c onstructional, area calculations include sections of length not greater than b each
side of the border in the area of effect of local load (Figure 16a);
-
When placed in a local load across the entire width boundary structures, area calculation
A bfilter2 y area
integrated A loc1 ( Figure 16b);
91
TCVN 5574: 2012
-
When the load locally located in the seat pillow purlins or beams, area calculations include the width by depth pillow on
structural purlins or beams and length not greater than half the distance between the beams wood or beam adjacent purlins or girder under consideration (Figure 16C); -
If the distance between the beams (purlins) greater than twice the width structures, the width of the area calculated by the total
width of the beams (purlins) and twice the width structures (Figure 16D); -
When local load set at an angle structures (Figure 16e), area calculation A; loc1
local compressive
-
A bfilter2 y area
When local load placed on a portion length and width component part, the area shown in Figure 16f calculations. While there
are a few loads with such characteristics, the area calculation is limited by the line passing through the midpoint of the distance between the point of the load placed adjacent; -
When the load placed on the bulge locally by wall or walls with a T-section, area calculation A bfilter2 y local compression area
-
A loc1 ( Figure 16g);
When determining the area calculations for complex shaped cross section, irrespective of the area where their connection with
loading areas can not be guaranteed with the necessary reliability (Figure 16h). NOTE: For local load by beams, purlins, lintel and the other bending structure, when defining the area loc1 nd Aa
Ad filter2 epth measured from the edge bearing take no larger than 20 cm.
6.2.5.3 Calculate local compressive structures made of concrete reinforced with heavy indirect form of welded steel mesh should meet the following conditions:
•
(103)
ARN1
,loc red b
Inside: A loc1
is compressible local area;
R,
is converted prismatic intensity of concrete when calculating local compressive, is determined by the formula:
red b
, red b
here:
• RR • bb • • •
R xy, s s • xy
(104)
R, s xy , • , • xy notation as in 6.2.2.13. • b •
3
(105)
/ 2 AA loc loc 1
but not greater than 3.5;
• S is coefficient considering indirectly reinforced area in the local compressive, for diagram Figure 16b, e, g taking S
•
= 1, which reinforced indirectly included in
calculated on condition horizontal steel mesh to put on a smaller area is not part of the area is limited by the dashed line on the diagram in Figure 16, respectively; for diagram Figure 16a, c, d, f coefficients S
• formula:
92
be determined by the
TCVN 5574: 2012
• S •
4•
of 535
loc
(106)
AAeffirst
here:
A tef he concrete area is located in the area bounded by the outer bars of reinforced steel mesh used as
indirect and must satisfy the condition A loc1 •
A •ef
A loc 2
B. Calculation of compression perforation
6.2.5.4 Structural slab (not horizontal reinforcement) subjected to force evenly distributed over a limited area should be calculated against compression Puncture conditions: • •
hu
bt m
RF 0
(107)
Inside:
F
the compression force perforation;
•
coefficients, taken on:
u m
+
heavy concrete: ..................................... 1.0
+
Concrete small particle: ................................. 0.85
+
Lightweight Concrete: ....................................... 0.8
The average value of the perimeter on the bottom and the bottom under compression tower perforation perforation formed when compressed, within the working height of the section.
When determining m
u and F h ypothesized that the compress perforation occurs in the slope of the tower have small bottom area
area of effect of compression force under perforation, while the side panels at an angle of 45 o from horizontal (Figure 17a).
Perforation compressive force F t aken by compression forces on the tower perforation, minus the load against compression caused greater effect on the bottom of the tower caused compression (taken in plane tensile reinforcement). If so bearing diagrams, compression perforation occurs only under the side towers have greater inclination 45 o ( f or example in Figure 17b pile station), the right side of the condition (107) is determined for the actual tower's riddled with compression 0
ch . Meanwhile, the bearing capacity is taken not greater than the value corresponding to the compression tower riddled with
• , 40 hc here c t he length of the side of the tower slides up horizontally compressed punctured. 0 ,
93
TCVN 5574: 2012
a)
b)
A loc 2
A loc first
A loc 1 = A loc 2
b
b
b b ab
c)
A
d)
A loc 2
l / 2 l / 2
a
b
b bb
A loc first
l • 2b 2b
e)
l • 2b 2b
A
A loc 2
A loc first
l> 2b
l> 2b
A loc 1 = A loc 2
f)
A loc 2
A loc first t s r i f
c
t s r i f
b
a
b
t s r i f
c 2 • b
b b first
a first
g)
c 2 • b
t s r i f
c
a
hour)
A
A loc 2 2
b b t s r i f
c A loc first
A loc 1 = A loc 2
t s r i f
c
b 2
a) when a local load on the entire width of the structures; b) when a local load on the entire width is in the edge components; c, d) when the load in place upstairs locally purlins or beams; e) when a local load components placed in one corner; f) when the load placed on the part of local and partial width length or the payload components set up locally convex portion of the wall or w alls; g) local load placed on pillars wall; h) section of the form complex IMPORTANT INSTRUCTIONS:
A loc1 is compressible local area; A filter2
the calculated area under compression locally;
A
the minimum area to put wire mesh, which reinforced indirectly included in the calculation formula (104).
Figure 16 - Diagram calculation of reinforced concrete structures under compression locally
ninety four
TCVN 5574: 2012
a)
b) F
F
0
r u o h
0
r u o h
45 o
c 45 o
a) when the side of the tilted tower riddled compressed 45 o; b ) when the compressed side of the tower at an angle greater perforation 45
o
Figure 17 - Diagram calculate perforation compressed reinforced concrete structures
When within tower riddled with compression reinforcement belt placed perpendicular to the surface, calculations should be carried out under the following conditions:
•
but not greater than power b
b
•
0, 8
(108)
FFF sw
2 F . b
F d egree right-hand side of inequality (107), and
F t he entire sum due shear reinforcement belt
sw
(Cut to the side of the tower) bear, be calculated using the formula:
sw
•
•
ARF sw sw
(109)
here, R sw not exceed the value corresponding to reinforced CI, AI. When mention transverse reinforcement,
F t sw ake not less than
0, 5 F b
.
When arranged reinforced belt on part limited near placements concentrated load, need to perform additional calculations according to the conditions (107) for tower compression caused bottomed out within the perimeter of the sections reinforcement horizontal.
Horizontal reinforcement should satisfy the requirements in 8.7.8.
C. Calculation tear 6.2.5.5 Reinforced concrete structures were tear due to the effect of the load placed on the lower edge or in the range of height section (Figure 18) should be calculated according to the following conditions:
• • first• • •
S
0
• •hh• F • • •
(110)
AR sw sw
0
S
F
hour S
father
r u o h
r u o h
hour S
Figure 18 - Diagram tear calculating reinforced concrete structures
95
TCVN 5574: 2012
In formula (110): F
the tear force;
hour S
is the distance from the position of force to tear reinforced central section along;
•
the total shear resistant reinforced by additional belt placed on the tear length a AR sw
sw
equal: • 2
S
(111)
BHA
•
here: b t he width of the transmission area tear. Value a nd b d etermined depending on the characteristics and conditions set loads tear up structures (placed on the coil, or hour S contiguous structures, etc ..).
D. Calculation crease beam 6.2.5.6 When the recess of the bar located at the domain folded tensile, transverse reinforcement should be sufficient to:
a)
Forces in longitudinal tensile reinforcement is not anchored to the compressive region:
• first
b)
ARF ss • cos 2
(112)
first
2
35% synergy in all the bars along the tensile: • 0, ARF
2
•ss cos 7 first
(113)
2
Transverse reinforcement requirements as calculated from the above conditions should be located on an approximately length
•3 tg hs 8
• (Figure 19).
The total projection of forces by horizontal reinforcing bars (rebar belt) located on this segment of the angle bisector to not smaller concave •
1
•
FF 2• • , mean: AR cos • • sw sw
•
• 1 FF • 2
(114)
in the formulas from (112) to (114):
A S
is the area of the entire cross section of the longitudinal tensile reinforcement;
A S first
is the area of the entire cross section of the longitudinal tensile reinforcement is not anchored to the compression zone;
•
• •
is a concave corner in the tensile structures; R sw the total cross-sectional area of transverse reinforcement within s;
the angle of the horizontal bars compared to the angle bisector •;
NOTE 1: The horizontal reinforcement must embrace the entire longitudinal tensile reinforcement and solidly anchored in the compression zone; NOTE 2: When the angle • • 160 o, can put vertical tensile reinforced continuously. when the • < 160 o then some or the entire longitudinal tensile reinforcement should be set apart and solidly anchored in the compression zone
96
TCVN 5574: 2012
s/2
s/2
r u o h
A s1
3 • / 4
2 / h
A s1 • •
A S
A S
Figure 19 - Diagram calculations and structural beams crease
6.2.6 Calculation reservation details available
6.2.6.1 The anchor bars welded steel perpendicular to the plane of the details in place, under the eff ect of bending moments M, force N p erpendicular to them and shear forces Q b y static load placed in the plane of symmetry of the details in place (Figure 20) should be calculated according to the formula: 2
first ,first
•
• QnA • • •• security •• security • • • • 2
security
(115)
R S
Inside: A
security
N
security
the total cross-sectional area of the anchor bar is located in the biggest bearing anchor line;
is the greatest traction in a row anchor bar: •
security
Q
security
•
(116)
z MN n N security
the shear force transmitted to a row of anchor bar:
•
•
security
'
0, 3 NQQ security
(117)
n
security
N •security
is the largest spa in a row compression anchor bar, which is determined by the formula:
' security
•
•
(118)
z MN n N security
In the formulas from (115) to (118): M, N, Q r espectively torque, axial and shear forces exerted on the details in place; Torque is defined for shaft located on the outer edge of the plane and passing through the focus of all the anchor bar;
n
security
is the anchor of every bar along the shear force; if transmission does not guarantee slip Q
are up all the anchor bar, then when determining the shear force
Q jsecurity ust to mention no more than 4 rows anchor;
z
is the distance between the outermost rows anchor bar;
•
is the coefficient, which is determined by the formula (119) when the anchor rod 8 mm diameter and 25 mm, with heavy
concrete, concrete grade granules from B12,5 to B50 and B12 supplied from lightweight concrete , 5 to B30, • i s determined by the formula:
97
TCVN 5574: 2012
475
3
(119)
b
• •
• • security RAR 1 s
• • 0 1,15
but took no greater than 0.7; for heavy concrete and concrete granules larger B50 levels, coefficients
•
take for granted, such as B50; for lightweight concrete greater level B30 B30 take as for granted;
here,
R,b
A
is the cross-sectional area of each tensile bar anchor largest, measured in square centimeters (cm
•
security 1
R u S nit is megapascan (MPa); 2);
coefficient, taken as follows:
+
for heavy concrete: 1.0 degrees;
+
concrete granules for group A: 0.8 degrees; Group B and C: 0.7 degrees;
+
for lightweight concrete: degree
• m
300 2 ( m •
is the average density of the concrete
cardboard, in kilograms per cubic meter kg / m 3);
•
coefficient, determined by the formula:
(120)
• • 1 1• •
but not less than 0.15;
here:
• •
0, 3
security
QN
when the N • security > 0 (can be compressed)
security
• •
0, 6
when the N • security • 0 (not under compression)
QN
If in the anchor bar without traction coefficient • d egree 1. Sectional area of the anchor bar in the remaining rows have taken the cross-sectional area of each tensile most.
In the formulas (116) and (118) force N i s considered positive if the preset direction from details out (Figure 20), is negative if the preset N,
direction into details. If force security
N • security and shear forces
Q c alculated from the security
formula from (116) to (118) is negative, then in the formulas from (115) to (117) and (120) we were taken to 0. In addition, if N < 0 , then the formula (117) taken
security
N • = N.
When the detailed layout built on the upper surface (the concrete), the ratio of component • be reduced by 20%, while the value
N •security get zero.
98
security
TCVN 5574: 2012
first
Q M z
N
first
1-1
Figure 20 - Diagram internal forces acting on the reservation details available
6.2.6.2 In the reservation availability anchor bars welded at an angle of 15 o 30 o, T his oblique anchor rods are bearing slide (when Q > N, with N t he tear force) according to the formula:
, security inc
•
•
'
0, 3 NQA security
(121)
R S
Inside: A
inc security
N •security
the total cross-sectional area of the anchor bar oblique;
see 6.2.6.1.
When it needs more anchor bar set perpendicular, calculated using the formula (115) with
• •
, And value first
Q p security ick
10% of the shear force values determined by the formula (117).
6.2.6.3 Structural details of the link to ensure that the anchor bar work scheme selected calculation. The external parts available reservation details and links are welded standard steel structure design ISO 338: 2005. When calculating the ciphertext and tear strength, they shall be considered as they l ink anchor match perpendicular bar. In addition, the thickness of the preset details are welded with the anchor bar should be checked under the following conditions:
•
R
dt 0, 25
(122)
security sq s
R
Inside: d
is the diameter of the anchor bar requirements as calculated;
R sq
is the calculated shear strength of the steel, taken according to ISO 338: 2005.
security
In the case of using the link type of welding to increase workspace copies when the anchor bar is pulled out of and as a basis, respectively, may be adjusted condition (122) for linking welding this.
The thickness of the need to satisfy the requirements of welding technology.
6.3
Calculation of reinforced concrete structures subject to fatigue
6.3.1 Calculation of reinforced concrete structures fatigue is done by comparing the stresses in the concrete and reinforced with corresponding fatigue limit
•
b fat
and
•
S, fat
of them.
99
TCVN 5574: 2012
Fatigue Limit of concrete
•
work
• b
• b of concrete ( first
b fat
first
degree calculating intensity of concrete b
ultiplied by the coefficient conditions R m
taken according to Table 15).
Fatigue Limit of Reinforced
•
work
• S 3 taken according to Table 24). Case when using reinforced with welded links, price
• S 3
of reinforcement (
Fatigue limits
•
S, fat
S, fat
degree calculating intensity of reinforcement S
• S 4
there are more factors including working conditions
(
• S 4
ultiplied by the coefficient conditions R m
taken according to Table 25).
Stresses in reinforced concrete and is calculated as for the elastic material ( according to the conversion section) subjected to external forces and compressive forces before P.
Inelastic deformation in the area of concrete compressive be mentioned by reducing the elastic modulus of concrete, taking the conversion coefficient of concrete steel • • 2 5, 20, 15, 10 respectively for concrete grade B15, B25, B30, B40 and higher. Coefficient
• repeat.
•
•
• , Inside b EE bs
E • the elastic modulus of concrete conventions when subjected to loads
E,b i t characterizes the ratio between stress and deformation full (including variables
E •b other than
elastic deformation and residual) of concrete, accumulated during load subjected to case if the condition (143) is not satisfied when the replacement value
R,
bt ser
by value
R, a rea information bt
converted area is determined regardless of the concrete tensile zone. 6.3.2 Structural fatigue calculation under section perpendicular to the longitudinal axis components should be conducted under the following conditions:
•
For concrete compressive
•
• b , max • •
b , fat
• R •
•
,
• fatR • s
(123)
first bb
For tensile reinforcement:
S
, max
• •
(124)
ss3
in the formula (123); (124): •
b , max
, •
S , max
is the biggest stresses corresponding compressible concrete and reinforced in
tensile. R b
the strength of the concrete calculations;
R S
the intensity calculation of tensile reinforcement.
When reinforced with welded links, in the formula (124):
•
,
• Rs fat •
• 3 sss4 .
In the region are concrete compressive test, the effect of the load loop to avoid tensile stresses appear.
Compression reinforcement without fatigue calculations.
6.3.3 Calculate fatigue on a section inclined to comply with the following conditions: reinforced horizontal bear full cooperation of the tensile stress that the effect along the length of structures in the central section of the exchange, this time to interest in the horizontal reinforcement
R p eople with
is removed by calculating intensity S coefficient of working conditions
100
• S 3
and
• S 4 (Table 24 and 25).
TCVN 5574: 2012
For components not horizontal reinforcement, should comply with the requirements in 7.1.3.1, but the formula (144), (145) replace the intensity of concrete calculations calculate bt R and
b
R,
bt ser
and
R,
ser b
respectively by intensity
• b given in Table 16.
R m ultiplied by the coefficient of working conditions
first
7 Calculation of reinforced concrete structures according to limit state Monday 7.1
Calculate concrete structures under the formation of cracks
7.1.1 General Principles Reinforced concrete structures are calculated according to the formation of cracks:
•
Perpendicular to the longitudinal axis components;
•
Oblique to the longitudinal axis structures.
7.1.2 Calculation of cracks formed perpendicular to the longitudinal axis components 7.1.2.1 For reinforced concrete structures subject to bending, pulling and compression forces on the eccentric interior cross section perpendicular to the formation of cracks is determined based on the following assumptions:
-
Still regarded as a flat section after deformation;
-
Elongation largest relative of concrete tensile fibers by outermost
-
Stresses in the concrete compressive zone (if any) shall be determined taking into elastic deformation or elasticity of concrete.
2,
/
ser bt
erb ;
Meanwhile inelastic deformation is mentioned by reducing the distance the core r ( f ocus distance from the exchange section to the farthest point of the core tensile), see 7.1.2.4;
R, bt ser ;
-
Stresses in concrete in tension zones evenly distributed and valued by
-
Stress in tension reinforcement does not equal the total algebraic stress, corresponding to part deformation of concrete that surrounds
it, and the stress caused by shrinkage and creep of concrete;
-
Tensile stresses in reinforced by algebraic sum of its pre-stressed (which included all the losses) and stress deformation with
increments of concrete that surrounds it. The instructions on this does not apply to components iterative load (see 7.2.1.9).
7.1.2.2 When determining the internal forces in cross section with reinforced structures do not take tension anchors, on the length of the transmitted stress p
l prestressed reinforced in sp
(See 5.2.2.5) when calculated in accordance with the formation of cracks to mention the reduction
•
and sp • •
by multiplying by a factor of
5
• S under section 5 in Table 23.
7.1.2.3 Calculation of reinforced concrete structures with compressed axially tensioned, bearing pull chord N s hould be conducted under t he following conditions:
• NN crc
(125)
Inside: N crc
is the internal force on cross section perpendicular to the longitudinal axis structures when cracks form, defined by the formula:
•
bt crc ,ser
•
• 2 •
S
• • PAARN
(126)
101
TCVN 5574: 2012
7.1.2.4 Calculate bending structure, eccentric compression, as well as pull eccentricity according to t he formation cracks comply with the following conditions:
(127)
MM • crc r
Inside: M r
the torque caused by external f orces located in a side section being considered for the axis parallel to the axis and passing neutral point away from the core area of the cross section of this t ension more;
M crc
the anti-cracking torque of section perpendicular to the longitudinal axis structures when cracks form, defined by the formula: •
• MWRM rp
(128)
M t ensioning torque is due P f or shaft used to determine rp
M; s r eal of torque
crc
here:
,
pl ser bt
is determined based on the direction of rotation ( "plus" when the direction of rotation
M arp nd
M isr contrary
different, "but" when they overlap). tensioning P t o be considered:
+
For pre-stressed structures: external compression force;
+
For non-tensioned structures: external traction and is determined by the the formula formula (8), (8), in in which the value of of S
•
and S • •
in the stretch does not get reinforced by prices
loss value of concrete shrinkage under section 8 of Table 6 (as with reinforced front drag on the base);
Value
M are defined as follows: r +
For bending structure (Figure 21a): r
+
• MM
For eccentric compressive structures (Figure 21b):
• NM r • +
0
• re•
(130)
For tensile structures eccentricity (Figure 21c): • NM r•
Value
(129)
0
• re•
(131)
M a rp re defined as follows: -
When calculated according to the formation of cracks in the tensile section due to external forces, but under compression by the compression force before (Figure 21), determined by the formula:
rp
-
•
PM • 0 p • re•
(132)
When calculated according to the formation of cracks in the tensile zone of the section due to compressive forces before (Figure 22), determined by the formula:
rp
102
•
• PM
0 p
• re•
(133)
TCVN 5574: 2012
a)
b) N A ' S 0
e r 0 e r
1 A ' S
x h
M
m 0
x h
2
e
x
r
r e
m 0
e
2
P
x h
R bt, ser
A S
r
h
first
+ m 0
+ m 0
e
P
R bt, ser
A S
A ' S
c)
first
r u o h
r
m 0
x
e r
2
+ m 0
e e m 0
r
x h
+ 0
e A S
P
R bt, ser
N a - bending; b - when the eccentric compression; c - when pulling the eccentric;
IMPORTANT
INSTRUCTIONS: 1 - core point;
2 - emphasis conversion section.
Figure 21 - Map of the internal forces and stress diagram on a cross section of structures when calculated according to the formation of cracks perpendicular to the longitudinal axis components in the tension caused by external forces, but under compression by the compression force before
In the formulas from (130) to (133):
r i s the distance from the focus-section converted to points far from the tensile cores than are is checking the formation cracks: +
For the eccentric compressive structures, pre-stressed structures flexural tensile and eccentric, if they satisfy the following conditions:
• PN
(134)
the value r i s determined by the formula:
•
+
red
(135)
r • AW red
For tensile tensile structures eccentric, if not not satisfy the the condition condition (134), (134), the the r is determined by the formula: Wr
• • 2 • +
•
pl
'
• AAA • ss
(136)
For bending structure structure without without reinforcement strain, r i s determined by the formula:
103
TCVN 5574: 2012
red
(137)
r• AW red In the formulas (135) and (136):
• •
•
first ,6 •
R,
(138)
bb ser
but take not less than 0.7 and not greater than 1.0; here:
•
b
is the biggest stress in the compressive zone of concrete due to external forces and tensioned, is calculated as the objects under
section elastic converted; etermined as directed in 7.1.2.6; W d pl
• •
EE bs .
For the cross section of the connecting structure and texture combinations block does not use glue in the joints, when calculating them in the
R,
formation of cracks (beginning expansion joints) value
bt ser
in the formula (126)
and (128) are taken to zero. A ' S
R bt, ser
x h
r
r u o h
m 0
e
x
r -
twelfth
m 0
e
b
N
A S
IMPORTANT INSTRUCTIONS: 1 - core point;
2 - emphasis conversion section. Figure 22 - Diagram internal force and stress diagrams in cross section when calculating structures according to the formation cracks perpendicular to the longitudinal axis components
in the tensile compressive strength due to previous causes
7.1.2.5 When calculated according to the formation of cracks in the segment for cracks in the initial compressive (see 4.2.9), the value
M t he tension due to the effect of external force is determined by the formula crc (128) should be reduced by a quantity
•
crc
• •
MM . crc
Coefficient • i s determined by the formula: • • • • •
If the value • c alculated as negative, 0 degree.
104
first ,
•0 5
,
•
•9 • •1 • • •
m
•
(139)
TCVN 5574: 2012
In formula (139):
• m is determined by the formula (171) for areas with initial cracks, but take not less than 0.45.
A
YHY
• •
•
AA
S
(140)
'
•
ss
but not greater than 1.4; here: Health i s the distance from the focus-section converted to concrete tensile fibers together by external forces outside.
For structural steel reinforcing bar steel fiber and A-VI group, A T- V II, value • c alculated using the formula (140) is reduced to 15%.
7.1.2.6 Bending resistance torque pl
W t he conversion section to the outermost tensile fibers (which include variable
inelastic form of the concrete tensile zone) is defined by the formula (141), assuming no axial force N a nd tensioning before compression P:
W
pl
•
2•
b 0
'0 0
• •
• • III
S
•
xh
•
• S bs 0
(141)
Position neutral axis is determined from the condition:
'0 b
'0
• •
S
xh SSS
• •
S 0
•
• •
• A bt
(142)
2
7.1.2.7 In the structural reinforcement structures prestressed (eg bar), when determining the internal forces on sections of structures that follow the formation of cracks, cross-sectional area the concrete tensile not with prestressing will not be included in the calculation.
7.1.2.8 When examining the ability structural loss bearing capacity simultaneously with the formation of cracks (see 4.2.10), the internal forces of the forming section cracks are defined by the formula (126) and (128) , but rather
R,
bt ser
1.2
R,
bt ser
• and coefficients sp
degree 1 (see 4.3.5).
7.1.2.9 The calculation according to the formation of cracks when the load loop is done under the following conditions:
• Inside:
•
bt
•
bt bt
(143)
R, ser
the tensile stress (in-line method) largest in the concrete, as determined in accordance
6.3.1. Tensile strength of concrete calculations job
R,
bt ser
in formulas (143) to mention coefficient conditions
• b first taken from Table 16.
7.1.3 Calculating the cracks formed oblique to the longitudinal axis components 7.1.3.1 The calculation according to the formation of cracks skewers should be done under the following conditions:
•
• •
R,
surfaces 4
ser bt
(144)
Inside: 105
TCVN 5574: 2012
• b 4
the coefficient of working conditions of concrete (Table 15), defined by the formula:
• b 4 •
• • first 0, 2
/mc
b,
(145)
• • BR ser
but not greater than 1.0; here:
• coefficients, taken on: + heavy concrete: .............................................. ...................... 0.01; +
Granulated concrete, lightweight concrete and concrete honeycomb: ............... 0.02;
B is superior compressive strength of the concrete, in megapascan (MPa). Value B
•
take not less than 0.3.
The tensile stress value and the compression in concrete
•
( mc ) mt
•
MT
•
• • 2
yx
•
•
• and MC
• • • • •
• • 2
is determined by the formula:
2
yx
• • • •
(146)
2
• • xy
Inside:
•
•
the stresses in the concrete on the section perpendicular to the longitudinal axis due to external force structures and tensioned before causing compression;
x
the stresses in the concrete on the section parallel to the longitudinal axis components of the effect locally of jet pillows,
Health
centralized and distributed loads and compressive forces by prestressed reinforced belt and reinforced oblique causes;
• xy
the tangential stress in the concrete due to external forces and compressive forces reinforced by prestressed oblique caused.
•
Stresses
x
, •
and
Health
•
xy
are defined as for elastic material, except to stress caused by tissue
induced torque is determined according to the formula for the plastic state of structures. stresses
•
x
, •
in the formula (146) the sign "plus" if the tensile stress and the sign "minus" if the application
Health
compressive stress. stresses MC
•
in the formula (145) were taken in accordance with absolute values.
The test under the conditions (144) are made in the focus section in the exchange and the adjacent location between compressible wing with rib structures cross section or the letter T I.
•
When calculating structures using reinforced stretch no need to consider the reduction anchor prestressed sp
•
•
sp
on the length of the transmitted stress p
l
• S 5
(See 5.2.2.5) by multiplying by a factor of
and
under section 5
Table 23. 7.1.3.2 When there are loads effects loop, the calculation according to the formation of cracks that need to be done according to the instructions in 7.1.3.1, which calculates the intensity of concrete
working conditions
106
• b first taken from Table 16.
R,
bt ser
and
R,
ser b
have to mention us
TCVN 5574: 2012
7.2
Calculation of reinforced concrete structures under the expansion cracks
7.2.1 General Principles Reinforced concrete structures are calculated according to the expansion cracks:
•
Perpendicular to the longitudinal axis components;
•
Oblique to the longitudinal axis structures.
7.2.2 Calculating the cracks extending perpendicular to the longitudinal axis components
a,m m, is determined by the formula:
7.2.2.1 Crack width perpendicular to the longitudinal axis components crc
a crc • • • •
•
3• 20 ,
• 100 5 • •
3
d
(147)
E ssl
Inside:
•
• l
coefficients, taken on:
+
bending structure and compression eccentricity: by 1.0;
+
tensile structures: 1.2;
coefficient, taking the effect of: +
temporary short-term load and short-term effects of frequent load and long-term temporary load: .......................... .................................................. .. 1.00;
+
loop load, load regular and long-term temporary loads on structures made from:
heavy concrete:
in conditions of natural humidity .............. ............ .. 1.6 to 15 •
in water saturated state: ..................................... 1.20 when the state water and dry saturated alternate: 1.75 Concrete small particle:
Group A: ............................................... ......................... 1.75 group B: ................... .................................................. ... 2.00 group C: ......................................... .............................. 1.50 lightweight concrete and hollow concrete: .......................................... ...................... 1,50 concrete honeycomb ..................... .................................................. ................. 2.50
Value
• l
for small particles of concrete, lightweight concrete, hollow concrete, concrete honeycomb in water saturated state is multiplied by a
factor of 0.8; even when the state of water and dry saturated alternate coefficients are multiplied by 1.2;
•
coefficient, taken as follows:
+
reinforced with ribbed bar: ................ 1.0 107
TCVN 5574: 2012
•
+
Reinforced with smooth round bar: ............ 1.3
+
with fiber reinforced ribbed or cable: ..... 1.2
+
Reinforced with slippery: ............................. 1.4
the stresses in the bars
S
S outer layer or (when tensioned) increments of stress due to the effects of external forces, which are
determined in accordance with the instructions in 7.2.2.2;
•
is the reinforcement content of the section: take the ratio of the area of reinforcement S a nd concrete sectional area (with
working heights
d
hour a nd regardless of the channel under compression) but not greater than 0.02;
0
is the reinforcement diameter, measured in millimeters (mm).
For structures require level 2 anti-crack, crack width is determined with a total load of regular, long-term temporary and short-term
• l •
temporary coefficient
first ,0
.
For structures require level 3 anti-crack, crack width is determined with the long-term effects of frequent load, long-term temporary
• l •
coefficient
first ,0
. Short-term crack width is determined
as the sum of long-term crack width and breadth of cracking in the effect of short-term temporary load coefficient
• l •
first ,0
;
Crack widths determined by the formula (147) is adjusted in the following cases: If the central section of the bars S t he outermost layer of bending structure, eccentric compression, pull eccentricity with
a)
tot
0,
treatment a n crc eed
•
,8 0 heh , is a fiber tensile most one about 0
to be increased by multiplying by a factor of
•
a
2
•
0, 2 ha, The price
equal:
20 2 • 1
•
a
ha
•
(148)
3
but no larger than 3. b)
• •
For bending structure, eccentric compression from heavy concrete and make lightweight concrete with
2
0, 008
and
MM r 0• , Crack widths due to the short-term effects of all loads allowing identified by internal 0 corresponding to the torque caused cracks a = crc
linear interpolation between the values
in this guide with torque
0
•
crc
• bh• MM
2
R
bt , ser
nd value M acrc
, (Inside
• •
a iscrc calculated according to the
•15• / • ) But not great
0.6. Meanwhile long-term crack width due to frequent load and long-term temporary load is determined by multiplying the value found crc
a
• • 1
1
•
• •
rp r rl
2
• MMMM • , Inside rp
• l1 •
first , 8 •
•
due to the effect of all the loads with the score r2 l
MM • but not less than l crc
• .
here:
• , •
as well as in the formula (147);
M,r first M i sr 2the torque
M r espectively due to the effect of permanent loads, long-term temporary and r
because the entire load (see 7.1.2.4).
108
TCVN 5574: 2012
c)
For structures made of lightweight concrete and concrete hollow B7,5 and lower levels, value
ecessary a n crc
have increased 20%.
• S should be determined by the
7.2.2.2 stresses in tensile reinforcement (or increments of stress) Challenges for:
- Tensile structures chord:
•
S
• PN
•
(149)
A S
- Bending structure:
•
S
PM • • ezsp •
•
•
- Compressive structures with eccentricity, and eccentricity pull when
•
For tensile structures eccentricity when z = S
z ( I nside:
S
(150)
A z S
•
•
•
e o
S
0, 8 hour : 0
tot
•ze• P N • • ezsp •
•
(151)
A z S
0,
tot
•
,8 0 heh , value 0
•
S
is determined by the formula (151) with
z i S s the distance between the reinforced focus S a nd S •).
For components not prestressed tensioning value before compression P i s taken to zero. In formula (151), the "community" is taken when pulling the eccentric, the "minus" - the eccentric compression. When the position of the vertical traction N l ocated between the focus of reinforcement S and S •• v alue
e t S aken with the "minus". In the formulas (150) and (151):
z i s the distance from the central area reinforcement section S t o the point of the resultant regional compressive concrete section above the crack, which is determined according to 7.4.3.2; When the tensile reinforcement arranged in multiple layers under section height of the bending structure, eccentric compression, pull eccentricity has 0,
More coefficient
n
•
tot
•
, Stress ,8 0 heh 0
• S
calculated using the formula (150) and (151) need to multiply
equal:
• n •
•
• axh
•
• axh twelfth
(152)
Inside:
•• hx0 , worth • i s determined by the formula (164); a,first a r 2espectively, the distance from the central area of the entire cross section of reinforced S a nd the outermost layer of the fiber reinforced concrete tensile most. Value stress ( S
• + • sp ) R,
ser s
or when there are multiple layers of tensile reinforcement (
• • SN + • sp ) Does not exceed
.
109
TCVN 5574: 2012
On the passage structures with initial cracks in areas under compression (see 4.2.9), stressed the value before compression P to reduce a
•
quantity P
is determined by the formula:
•
•• PP
(153)
Inside:
•
is determined by the formula (139).
7.2.2.3 The depth of the initial cracks ,5 0 hour .V alue 0
hour i n areas under compression (see 4.2.9) is not greater than
crc
hour is determined by the formula: crc
• hh • • first , 2 • • m • •
crc
Value • i s determined by the formula (164),
•
m
(154)
hour 0
calculated using the formula (171) for the cracks
original. 7.2.3 Calculating the cracks extend oblique to the longitudinal axis components
Width cracks when reinforced belt oblique perpendicular to the longitudinal axis structures should be defined by the formula:
0,6
a crc • • l
•
d •
sw w
(155)
0 ws
hd•E ,
E b 1• 15• 2
• • w •
0
Inside:
• l
coefficient, taken as follows:
+
When told to load a temporary short-term and short-term effects of frequent load and long-term temporary load: ....................... .......................................... 1.00
+
When mention payload repeaters as well as long-term effects of frequent load and long-term temporary loads on structures made from: heavy concrete:
in conditions of natural moisture: .......................................... ................. 1.50 in water saturated state: ....................... ..................................... 1.20 as modified alternate between storm status water and air-dried: ....... 1.75 Granulated concrete, lightweight concrete, hollow concrete and concrete honeycomb: grab as in the formula (147);
•
taken as in the formula (147);
d w
is reinforced belt diameter;
• •
S
EE b ; •
A sw w •bs .
Stresses in reinforced belt is defined by the formula:
110
TCVN 5574: 2012
• sw •
• QQ b A sw
R,
but may not exceed
ser s
(156)
sh
01
.
In formula (156): Q a nd
Q r b espectively left side and right side of the condition (84) but rather the value first
coefficient
bt qual R e
R,
bt ser
• b 4 be multiplied by 0.8.
When no cracks perpendicular in the region are considered subjected to shear, ie satisfies the condition (127), lets mention the Q b b ear by component as calculated from the condition (144). first
increased shear Intensity calculation
R,
bt ser
and
R,
ser b
not exceed the respective values of B30 grade concrete.
a crc calculated using the formula (155)
For structures made of lightweight concrete and lower grade B7,5, value
must increase to 30%. When determining the width of cracks oblique short term and long term need to follow t he instructions in 7.2.2.1 on to mention long-term effects on the nature of the load.
7.3
Calculation of reinforced concrete structures under the closed cracks
7.3.1 General Principles Reinforced concrete structures should be calculated according to the closed cracks:
•
Perpendicular to the longitudinal axis components;
•
Oblique angle to the longitudinal axis st ructures.
7.3.2 Calculating the cracks closed perpendicular to the longitudinal axis components
7.3.2.1 To ensure close cracks perpendicular to the longitudinal axis for certain structures when subjected to regular load and long-term temporary load, must comply with the following conditions: a)
Reinforced in stretch S s ubjected to regular load, l ong-term temporary loads and temporary short term, appear to avoid
irreversible deformation must comply with the following conditions:
•
•sp • s •
0, 8
R,
(157)
ser s
Inside:
•
S
value increments tension stresses in reinforcement S due to the effects of external forces, are determined according to the formula
from (149) to (151).
b)
Section structures with cracks in the tension due to the effect of loads frequently, temporary load long-term and temporary
short-term need to always be compressed under the effect of loads frequently, temporary load length term legal and compressive
•
stress b not less than 0.5 MPa. Quantity b
•
in border tension caused by external forces
are defined as for objects subjected to elastic
external force and tensioning before compression.
111
TCVN 5574: 2012
•
7.3.2.2 For structures with cracks segment initial compressive region (see 4.2.9), the value Formula (157) is multiplied by the coefficient • number first , 1•1
first •
• • ,
remaining quantities P w hen determining stress
•
b
sp
in
be multiplied
• • • but not greater than 1.0; which values • i s determined as directed in 7.1.2.5.
7.3.3 Calculating the cracks closed structures oblique to the longitudinal axis
To ensure the closed cracks oblique to the longitudinal axis for certain components, both principal stress in concrete, determined according to 7.1.3.1 at the central exchange section when subjected to frequent load , long-term temporary loads, and compressive stress is worth not less than 0.6 MPa. Requirements are met through horizontal reinforcement (reinforced belt or oblique) tensioned.
7.4
Structural calculation of reinforced concrete structures under strain
7.4.1 General Principles 7.4.1.1 Deformation (deflection, rotation) of the component structures of reinforced concrete should be calculated according to the formula of structural mechanics, in which the value of the curvature taken into account shall be determined in accordance with the instructions in 7.4.1.2 and 7.4.3.
Value of curvature deformation of reinforced concrete structures are calculated from their original state, even when tensioned, from the state before compression. The initial curvature of the self-inflicted tensioning structures identified include content and location along with r einforced concrete sections and values before concrete compressive strength.
7.4.1.2 Camber is defined as follows: a)
For those segments that regional structures of its tensile cracks formed perpendicular to the longitudinal axis components is
determined as for elastic objects. b)
For the period of construction that in the tension of it cracks perpendicular to the longitudinal axis components: defined as the ratio
between the difference of deformation medium of fibers outermost regions under compression of the concrete and turn the average form of longitudinal tensile reinforcement with a working height of structures section.
Components or segments structures are considered no cracks in the tensile if cracks do not form when subjected to load frequently, temporary long-term and temporary short term or if they are closed when subjected to regular load and long-term temporary, in which the load taken into account the coefficient of reliability of load
• f •
0 first,
.
7.4.2 Determining curvature reinforced concrete structures on sections no cracks in the tensile 7.4.2.1 On sections where no cracks formed perpendicular to the longitudinal axis components, the full value of the curvature of bending structure, compression and pulling eccentric eccentricity should be determined by the formula:
• • • • Inside:
112
• • • • • • first •
1 •1 1 1
• • • • •2 •
• •1 • • • • • •3 • rrrrr •4
(158)
TCVN 5574: 2012
• • •
first •
• first• respectively in curvature due to temporary short-term load (determined in accordance with 4.2.3) and • ,• • • • 1rr • 2
due to frequent load, long-term temporary load (not including compression force before P), is determined according to the formula:
• 1 • • • • •
• • • • • • •
• 1
• r
• 1 • • • • • r • •2
1
EM bb
•
red
b 2
II red EM bb
first
(159)
Inside: M is due to external force torque corresponding (short term and long term) for the axis perpendicular to the surface
flat effect of bending moments and go through emphasis conversion section;
• b first is coefficient considering the impact of short-term creep of concrete, is taken as follows: +
For heavy concrete, concrete granules, lightweight concrete with fine aggregate types of solid and concrete honeycomb (for structural prestressed two layers made from concrete honeycomb and heavy concrete): degree 0.85;
+
• b 2
For lightweight aggregate concrete small hollow foam and concrete: 0.7 degrees;
is coefficient considering the influence of long-term creep deformation of concrete structures without cracks, which are t aken according to Table 33;
• first• •• is due to the convex curvature of the components of the short-term effects of pre-stressed compression P, • r • 3
is determined by the formula:
• • •
first •
0 p
• • • P first r E bb e I red •3
(160)
• first• •• is due to the convex curvature of the components due to shrinkage and creep of concrete when subjected to • • r 4 front downforce, which is determined by the formula:
• • •
first •
• • •4
• • •
•
bb
(161)
hr0
here:
• b , • b • is deformed relatively concrete caused by shrinkage and creep of concrete due to compressive forces before and is determined respectively at the focus reinforced longitudinal tensile and fiber concrete compressive outermost formula (162):
• •
•
; E
sb b s
• • •
•
•
(162)
E s
sb b
113
TCVN 5574: 2012
Value
• sb obtained a total loss of prestress shrinkage and creep of concrete •
Cardboard determined under section 6, 8, 9 Table 6 for reinforcement in the tensile set;
•
sb
Similar grab the tension reinforcement if they are set or not set in concrete compressive fibrous outer.
• • •
Meanwhile total
• 1 • 1 • • • • • •3 • rr • 4
P IE• eb 2 0p
take not less than •
first
bb
. For non-tensioned structures, values
red
• first• •• • first• •• and lets get zero. • • r r • • 3 4
curved
7.4.2.2 When determining the curvature of structures with cracks in the area initially under compression (see 4.2.9) value
• • •
first• •• r
, ••
first
first• ••
• r
and
2
• first• •• determined by the formula (159), (160) increased by 15%, while the value • • r 3
• first• •• determined by • • r 4
formulas (161) should be increased to 25%.
7.4.2.3 In areas with perpendicular cracks formed in the tension, but it is closed under the effect of loads are considered, the curvature • • •
first• •• r
, ••
first
first• ••
• r
and
2
• first• •• in the formula (158) is increased • • r 3
up 20%.
Table 33 - Coefficient
2
• b , the effect of long-term creep of concrete to distortion of structures no cracks 2 Coefficient •
Calculate the long term effects
b
, for structures made from
load heavy concrete, lightweight concrete, hollow
Concrete small particle group
concrete, concrete honeycomb (for structural prestressed concrete made from two layers of honeycomb and
A
B
C
1.0
1.0
1.0
1.0
a) from 40% to 75%
2.0
2.6
3.0
2.0
b) Less than 40%
3.0
3.9
4.5
3.0
heavy concrete)
1. The short-term impact
2. The long-term effects when air humidity surroundings:
NOTE 1: Classification of concrete granules group see 5.1.1.3. NOTE 2: When concrete alternation saturated conditions - dry, value
• b 2
need to multiply by a factor of 1.2 if
Long-term effects of bear loads. NOTE 3: When the air humidity around 75% higher than in the state of concrete and water saturation, value Table 33 must be multiplied by a factor of 0.8.
7.4.3 Determining the curvature of reinforced concrete structures on the sections with cracks in the tensile
114
• b 2
in Section 2a
TCVN 5574: 2012
7.4.3.1 In areas have formed cracks perpendicular to the longitudinal axis components in the tensile, flexure of bending structure, eccentric compression, as well as drag eccentric with rectangular section, tee, tee ( box) with , tot 0
•
0, 8 heh , need identified by the formula: 0
first
• 0
• • • •
• sss
• •• • •h N0v Eb bh•zh M r 0 •• f • AE •
b
• (163) tot
AE sss
Inside:
M t he torque on the axis perpendicular to the plane of the effects of t orque and goes through key reinforced center section S, since all external forces placed at one side of the section in question and stressed by compression before P c ause;
z
is the distance from the central section of reinforced S t he set point of the compressive forces in the area located above the crack is determined according to the instructions in 7.4.3.2;
•
•
S
b
is taken of the coefficients of the concrete work on the stretch zone tensile cracks, be determined according to 7.4.3.3;
is coefficient considering the uneven distribution of fibers deformed outer concrete compressive on the length of the cracks and is taken as follows: +
For heavy concrete, concrete granules, slightly higher concrete B7,5: ........ 0.9;
+
For lightweight concrete, hollow concrete and concrete honeycomb B7,5 and lower levels. 0.7;
+
For structures affected by the load loop, regardless of type and level concrete: ............................. .................................................. .............................. 1.0;
• f
is the coefficient, which is determined by the formula (167);
•
the relative height of the concrete compressive zone is determined according to 7.4.3.2;
•
coefficient characteristics of elastic-plastic state concrete compressive region, prepared according to Table 34;
N tot
it is the vertical force N and tensioning before compression P ( While pulling the eccentric force N taken with the "minus").
For structures without reinforcement strain, force P l ets get zero. When determining the curvature of the structures on the original paragraph cracks in areas under compression (see 4.2.9), the value P
reduced amounts P
•
is determined by the formula (153).
For compression bending structure and eccentricity made from heavy concrete, as curvature caused by torque
•
M crc <
•
M r < 2
2
crc
• • bh M R
, ser bt
•,
determined by linear interpolation between the values: M p r ermitted 2 crc re defined as for the continuous elastic bodies according to 7.4.2.1, 7.4.2.2, M a
Curvature caused by torque
7.4.2.3. •
Curvature caused by torque
•
2
crc
bh M R • •
, ser bt
•
is determined as directed in this. Coefficient • OK
determined as directed in 7.2.2.1b and reduced 2 times when taking into account the long-term effects of frequent load and long-term temporary load.
115
TCVN 5574: 2012
Table 34 - Coefficient • c haracterized by elastic-plastic state concrete compressive zone
Coefficient •• for components made from
Long-term effects nature
Hollow
Heavy concrete,
load
Concrete small particle
concrete
lightweight concrete
ong
the group
A 1. Short-term effects
Concrete structure
B
C
0.45
0.45
0.45 0.45 0.45
0.45
a) 40% - 75%
0.15
0.07
0.1
0.2
b) <40%
0.1
0.04
0.07 0.05 0.1
2. Long-term effects, while air humidity environment
the pulse
around:
0.08 0.15
0.1
NOTE 1: The concrete granules for in 5.1.1.3; NOTE 2: When concrete changes saturated state - dry, value • n eed to multiply by a factor of 1.2 if subjected to long-term loads.
NOTE 3: When the humidity of the ambient air is higher than 75% and the concrete in a state of water saturation, value
• under Section 2a of this table need to divide by
0.8.
7.4.3.2 Value • is calculated using the formula:
1
• • • •
•5 1 •• • • •
first ,5
•
11
10 • •
• • f
(164)
S ,
of 5 • 5 heh tot 0
but took no greater than 1.0. compressed, the sign "minus" when force N i stot
The second term of the right-hand side of formula (164), take the "community" as the force
N i stot pulled (see 7.4.3.1). In formula (164):
•
coefficient, taken as follows:
+
For heavy concrete and lightweight concrete: ........................ 1.8
+
For concrete granules: ........................................... . 1.6
+
For hollow concrete and concrete honeycomb: ..................... 1.4
• •
M bh R 0
116
(165)
2
, ser b
TCVN 5574: 2012
• • • • ff • • •
• •
'
ff
hour •
• •
•
(166)
2 1 hour 0' •
•
•
'
• vhbb f
•
2
•
'
A S
(167)
bh 0 e,
tot's
N f tot or reinforced central section S,c orresponding to models
is the eccentricity of force
yeast M ( s ee 7.4.3.1), is defined by the formula:
, tot's
e•
(168) NMtot
Value z i s calculated using the formula:
•
0
• • • • • •
• • hhhz 0' • •1 2 •• fff • • • • • • •
• •
2
(169)
0, 97
•
For compressive eccentric structures, values z should be taken not greater than
•
For rectangular rectangular duct structures structures or or tee tee off off in in the tensile zone, in in the the formula (166) and (169) (169) instead instead qual a •2 hour • e
f
f
• •
hh • of calculated as for letters section
b •.
The width of the wing calculated
7.4.3.3 Coefficient S
;
tot's
hour • = 0 corresponds with or without reinforcement S •;
or f
The wing section is located in a pressurized area, as Update the width
e,
•
f
b • i s determined according to the instructions in 6.2.2.7.
for structures made of heavy concrete, concrete granules, lightweight concrete and structural two
classes for pre-stressed concrete honeycomb made from heavy concrete and is determined by the formula: 2
•
but not greater than 1.0; which took
S
•
first , 25
• • • • ls m
,tot's
• • m first
• 3 •of 15 • •tot8 sm ,
(170) / heh 0
• /, 0 2/ • l S heh first
For bending structure is not pre-stressed, the last term on the right side of formula (170) lets get zero. In formula (170):
• ls
is considering the influence coefficient term effects of weight, taken from Table 35;
e s , tot is considered the formula (168);
117
TCVN 5574: 2012
•
,
bt m pl
• •
WR ser
(171)
• MM rp r
but not greater than 1.0; here
W pl M,r
see formula (141);
M srp ee 7.1.2.4, which torque is considered positive if the cause drag reinforced S.
•
Table 35 - Coefficient ls
Coefficient • ls
level with concrete
Long-term effects on the nature of the load
Larger B7,5 Less than or equal B7,5 1. Short-term effects, when reinforcement is a - Lubricants
1.0
0.7
- flanged
1.1
0.8
b - steel fibers
1.0
0.7
2. Long-term effects (not dependent on the type of reinforcement)
0.8
0.6
form steel bar
For a layer structure made of honeycomb concrete (not prestressed), value
•
S
is calculated as
formula:
•
S
•
0, 5
• • l
(172)
MM ser
Inside: M t he bending resistance of the structural cross section calculations with intensity endurance calculation ser reinforced concrete and the calculation according to the second limit state;
• l
coefficients, which are obtained as follows:
+
While short-term effects of the load for the reinforced ribbed: .......................... 0.6
+
While short-term effects of weight for smooth reinforced: ........................... 0.7
+
While the long-term effects of weight does not depend on the shape steel section: ............................... .................................................. ........................... 0.8
For texture calculated fatigue value
7.4.3.4 Full curvature r recipe:
118
•
S
in all cases be taken by 1.0.
1 to paragraph cracks in tension zone should be determined in accordance
TCVN 5574: 2012
• • • •
• • • • • • •
1 •1 1 1
• •
• • • • • •3 2 1 •
•1 • • • • • rrrrr •4
(173)
Inside: • first• •• the curvature due to the short-term effects of the entire load used to calculate deformation as directed in 4.2.11; • • r first
• first• •• the curvature due to the short-term effects of frequent load and long-term temporary load; • r • 2 • first• •• the curvature due to the long-term effects of frequent load and long-term temporary load; • • r 3 • first• •• the camber shrinkage and creep of concrete when subjected to compressive forces advance P,i s determined by the formula (161) • • r 4 and follow the instructions in 7.4.2.2. • • •
flexure
value
•
S
first• •• r
, ••
first
first• ••
• r
and
2
• first• •• is determined by the formula (163), in which • • r 3
• first• •• and • first• •• be charged with • • • r first • r 2
• first• •• • worth • r are 3
and • w ith short-term effects of the load, while
•
S
and •
• first• •• • first• •• and • is negative, they are taken to zero. • • r 2 • r 3
with long-term effects of the load. If the value
7.4.4 Determination of deflections
7.4.4.1 sag m
f d eformation caused by bending is determined by the formula: l
•
• 0
•
M f •
•
first •
• dx r • XXM
(174)
Inside:
M i sx the bending moment at section x due to the effect of forces unit put towards transposition need determination of components in section x o n length looking deflection rate;
• first • is a full curvature in section x l oad caused by the deflection to determine; value r • r •• • x
first
is determined according to the formula (158), (173) corresponding to the passage and has no cracks; seal of r 1 comes in line with the curvature graph.
For structures (not reinforced stretch) bending cross section constant, cracks, on each piece bending moments do not change the seal, allowing the curvature for the section with maximum stress, curvature the remaining section of the piece that was taken out of proportion with the value of the bending moment (Figure 23).
hl •
7.4.4.2 For when bending structure this case, the full deflection tot
f
ten
should mention the impact of cutting force to sag. In
by total deflection by bending m
f and deflection due to shear strain
f.q 119
TCVN 5574: 2012
a)
b)
c)
a - load diagram; b - bending moment diagrams; c - chart curvature
Figure 23 - Chart bending moment and curvature of structures reinforced concrete with constant cross section
7.4.4.3 sag q
f b y shear strain is defined by the formula:
l
(175)
f q • • Q x x • dx 0
Inside:
Q x
the shear force in section x by force unit in the direction of displacement effects should define and put in the necessary determination section deflection;
• x
the shear strain, defined by the formula:
• x •
first ,5
• bx
GQ hb0 2
• crc
(176)
here: Q t he shear force at section x d ue to the effects of external forces; x
G t he sliding module of concrete;
• b 2 is coefficient considering the influence of long-term creep of concrete, taken from Table 33; • crc is coefficient considering the influence of cracks on the shear strain, taken as follows: +
On sections along the length of structures no cracks and fissures oblique perpendicular to the longitudinal axis components: 1.0 degrees;
+
On the segment only cracks oblique to the longitudinal axis components: 4.8 degrees;
+
On paragraph only perpendicular cracks or fissures and cracks oblique and perpendicular to the longitudinal axis structures, taken by the formula:
• crc •
I 3 ME x red b
120
•1• • • • r • x
(177)
TCVN 5574: 2012
M,x
here
• 1 -• respectively due to external force torque and full curvature • • r •• x
section in section x l oad caused by the deflection. 7.4.4.4 For the characteristics of thickness less than 25 cm (excluding the statement of the four sides) placed wire mesh flat, with cracks in the tensile value deflections calculated using the formula (174) to be multiplied coefficient 3
• • • •
hour 07 hour • 0
•
, but took no greater than 1.5 ( 0
easured in centimeters (cm)). hour m
, 0 •••
7.4.4.5 When calculating the components put a layer of reinforcement (Figure 24) using finite element method (or methods other mathematicians), allows the use of equation (163) by equations of physics symmetric format:
first
•
• •0
• NBMB • • • NBMB 22 •
•
r
11
•
12
(178)
twelfth
Inside:
•
act
• •
11
twelfth
22
•
B
•
PNN
• • b • • zzbs • • •• f • • • first
(181)
• • zzz • • bs sb • z bh • • •• f • • • 0 E b • ~ • • • AE ss bs
(182)
•
0
•
• ~bh • b
2
•
• • 2 • • zzbs • • •• f • • • first
B
(180)
• • AEE sss •
2
B
•
•
act
(179)
0 p
first
•
•
• Pe MM
2
sb
0
E z bh
• ~ b
•
•
2
• • AE ss • z
bs
• ~ •2• • 0
(183)
(184)
the elongation or shortening along the y axis;
M torque act due to external force is placed on one side section being considered for the y-axis;
N act
is the force along the y-axis set at, take the "public" when causing drag;
z,S b z corresponding to the distance from the y axis setpoint reinforcement forces of drag and to join forces in concrete under compression;
•
be determined according to 7.4.3.2;
•
coefficient, taken from Table 34;
• f
coefficient, determined by the formula (167) do not mention the reinforcement in the compressive set of
section;
• •
S
b
determined in accordance with 7.4.3.3;
determined according to 7.4.3.1.
121
TCVN 5574: 2012
Y-axis is within the height of the section in order to work to simplify the diagram properties. If the y-axis is higher than the focus area of z s hould take with a negative sign.
the compressible section, the quantity b • b
•
b A b
b
M
z
N
•
Health
S
z
S A S
Figure 24 - Map of the internal forces and stresses chart on sections perpendicular to the longitudinal axis structures, there is a reinforcement layer as calculated under strain
For the second term in the formula (179), the "minus" if power is removed P s et lower than the y axis, if force P s et higher y-axis the sign "plus". For the first term of the formula (180), the "community" is taken as the force is taken as the force act
N is pulled, and the "minus"
act
N i s compressed.
7.4.4.6 When calculating structures reinforced with laminated set (Figure 25), should use the physical equation general form:
• •• • 1 DN • D r 22• 0 • twelfth •• 1 • Dr DM 11
•
•
•
12 0
(185)
Inside:
~ •11 •
'1 2
z z •AED
i • 1
•
•
si si si j n
2
AE •
sj sj k f
0
•• sj • • 1 •
•
si•
E bh zv2 bbb
(186)
~ •12 •
z z •AED
i • 1
•
•
si si si j n
'
AE •
sj sj k f
0
•• sj • • 1 •
E bh zv
(187)
bbb
•
si• first
~
•22
•
•
i •
1
•
si si j n
•
'
k sj sj • AEAED •• f • • 1 •
si • first
0
E bh v
•
(188)
bb
with
i
is the number of longitudinal tensile reinforcement;
j
is the number of vertical bars under compression;
• first
the relative height compressive zone of section: degree
• •
x 01 1
•
f
z,si
122
is calculated using the formula (167) do not mention the reinforcementS •;
z i sj s the distance from the central core th i a nd th j t he y-axis.
; hour
TCVN 5574: 2012
z,si
In formula (187) values
z,sj
z t b aken positive sign if under the y axis, the case
reverse negative impression.
• sc1 A ' s1 • b A b • SCJ A ' sj • SCK A ' sk
1
b
x
M
j s
z
0 r u o h
N • SN A SN
i s
z
Health
• si A si • s1 A s1 Figure 25 - Diagram internal force and stress diagrams in cross section perpendicular to the longitudinal axis structure Events have placed multiple layers of reinforcement when calculated according to the deformation
Value first
•
• and si
in equations (186) to (188) allowed under 7.4.3.2 and 7.4.3.3 identify,
but in the calculation formula instead 0
• m equal •
•
•10mm 1 •
qual hour e
01
hour ,
Ae S qual
•
A
0 si 01i
• •
first , xh (As determined •) and 3 ,3 1 xh
hh0 ± • .
8 Requests structure 8.1
General requirements
When designing structures of concrete and reinforced concrete, to ensure the conditions of manufacture, the life and the work and of reinforcing steel and concrete need to make the request structure outlined in the this.
8.2 Minimum size of section structures 8.2.1 The minimum size of the section of concrete structures and reinforced concrete is determined from the calculation according to the force and by groups of limit states respectively, should be selected taking into account t he requirements economy, the need for unity of formwork and placing reinforcement, as well as the conditions of production technology components.
In addition, the section sizes of reinforced concrete structures need to choose as to ensure the requirements for reinforced arranged in cross-section (thickness of concrete protection, the distance between the bars, etc .. ) and anchor reinforcement.
8.2.2 The thickness of the whole block is taken not less than:
•
For roof deck: ............................................. ................................ 40 mm
•
For floor housing and public works: ................................... 50 mm
•
For the floor between floors of the manufacturer: ................................. 60 mm
•
For copies made from lightweight concrete, and lower levels B7,5: .................. 70 mm minimum thickness of the assembly is
determined from the condition ensure the required thickness of the protective layer of concrete and rebar layout conditions on the thickness (see 8.3.1 to 8.4.2).
123
TCVN 5574: 2012
The size of the cross section of the eccentric compressive components should be selected so that the piece
/ il
0
according to the
any direction shall not exceed: •
For reinforced concrete structures made of heavy concrete, concrete granules, lightweight concrete: ........... 200
•
For the column: ............................................. .................................................. ........................ 120
•
For concrete structures made of heavy concrete, concrete granules, lightweight concrete, hollow concrete: ... 90
•
For concrete structures reinforced concrete and concrete made from honeycomb: ................................ ........ 70
8.3
Concrete protection layer
8.3.1 Concrete layer to protect reinforcement forces should ensure the simultaneous working of the steel and concrete in all work phases of the structure, as well as protect the reinforcement from the effects of air temperature and similar impacts.
8.3.2 For reinforcement along the bearing (not tensioned, pre-stressed, prestressed pull on the pad), thickness of concrete protection needs to be taken not smaller diameter steel rod or cable and not less than:
•
In and wall thickness:
•
+
100 mm or less: ...................... 10 mm (15 mm)
+
Over 100 mm: .................................... 15 mm (20 mm)
Beams and girders in the ribs with a height:
+
Less than 250 mm: ............................. 15 mm (20 mm)
+
Greater or equal to 250 mm: ............ 20 mm (25 mm)
•
In column: ............................................... ................. 20 mm (25 mm)
•
In the foundation beam: .............................................. ..................... 30 mm
•
In the basement:
+
build: ............................................... .......... 30 mm
+
monolithic concrete layer lining when: ........................ 35 mm
+
whole blocks when no concrete layer lining: ............. 70 mm
NOTE 1: Values in parentheses (...) applied to outdoor structures or wet locations. NOTE 2: For structures in affected areas of the marine environment, thickness of concrete protection taken as prescribed by the current standards ISO 9346: 2012.
In a layer structure made from lightweight concrete and hollow concrete B7,5 and lower grade, thickness of concrete protection should not be less than 20 mm, while for the outer wall panel (without plaster) not be less than 25 mm.
For a layer structure made from concrete honeycomb, in any case protective concrete layer is not less than 25 mm.
124
TCVN 5574: 2012
In the areas affected by the salty steam, taking the thickness of concrete protection as defined in the corresponding standards in force.
8.3.3 Thickness of concrete protection for belt reinforcement, reinforcement and reinforced distribution structure should be taken not less than the diameter of the reinforcement and not less than:
•
When the depth of less than 250 mm components: ........................ 10 mm (15 mm)
•
When the depth of structures by 250 mm or more: .................. 15 mm (20 mm)
NOTE 1: Values in parentheses (...) applied to outdoor structures or wet locations. NOTE 2: For structures in affected areas of the marine environment, thickness of concrete protection taken as prescribed by the current standards ISO 9346: 2012.
In components made from lightweight concrete, hollow concrete have greater levels not B7,5 and concrete made from honeycomb, thickness of concrete protection for horizontal reinforcement taken not less than 15 mm, not dependent height section.
8.3.4 Thickness of protective concrete at the tip of the pre-stressed structures along the length of the communication stresses (see 5.2.2.5) should be taken not less than:
•
CIV group for bars, A-IV, A-III B: .................................................. ...... 2 d
•
For rebar group AV, A-VI, A-VI, A T- VII: ................................................ ....... 3 d
•
For reinforced reinforced cable cable types: types: ........................................... ........................................... .....................................2 .....................................2 d
(here, d m easured in millimeters (mm)).
In addition, the thickness of concrete protection in areas mentioned above must not be less than 40 mm for all types of reinforcing steel bar and not less than 30 mm for reinforced cable format.
Allow the concrete protective layer of reinforced stretch with no anchor at anchor or in the pillow section is taken like in the rhythm section for the following cases: a)
for structures tensioned with the force bearing transmit focus, when the details bearing steel and reinforced indirectly (reinforced
equal weld mesh or reinforced belt surrounding the reinforced vertical) placed under directions in 8.12.9.
b)
in villages, panels, MDF and pole foundations of power transmission lines when you place the additional horizontal reinforcement at the
tip structures (steel mesh, reinforced belt tight) as defined in 8.12.9.
8.3.5 In structures reinforced along prestressed tension on concrete and in the tubing set of steel, the distance from the surface structures to the surface of the tube to be taken not less than 40 mm and not less than the width of the tube placed steel in addition, the gap above to the side of the component is not less than 1/2 the height of the steel tube set.
When the tension in the reinforcement layout or on the outside groove open section, thickness of protective concrete is formed later through grouting methods or other methods to obtain not less than 30 mm. 8.3.6 To ensure easy set principles of rebar, wire mesh or steel frames to shuttering along the entire length (or width) of the components, the ends of the bars need to set the edge components a about are:
•
For structures with dimensions less than 9 m: ....................................... ............ 10 mm
125
TCVN 5574: 2012
•
For structures with dimensions below 12 m: ....................................... ........... 15 mm
•
For structures with dimensions greater than 12 m: ...................................... ....... 20 mm
8.3.7 Structure section in rings or box section, the distance from the bars along the inner surface of the components need to satisfy the requirements in 8.3.2 and 8.3.3. 8.4 Minimum distance between the bars 8.4.1 Distance waterway between the bars (or casing reinforced stretch) in height and width section should ensure the work simultaneously between reinforced concrete and are selected have to mention the convenience when placing and compacting concrete mortar. For pre-stressed structures should also consider the level of local compression of the concrete, the size of the equipment drag (click, clip). Components used in the table or vibrator dress when making should ensure that the distance between the bars allowed to pass through tight dress concrete mortar.
8.4.2 Distance waterway between the bars along not stretch or reinforced stretch is pulled on a pedestal, as well as the distance between the bars in the welded steel frame adjacent, taken not less than the diameter of the rebar largest and smaller values following provisions: a)
If you pour the concrete, the bars have a horizontal position or diagonally: not less than: for rebar is placed under 25 mm, with
reinforced on 30 mm. When reinforced under more than two layers arranged according to height, the distance between the horizontal bar (outside the bar at the bottom two layers) should not be less than 50 mm.
b)
If you pour the concrete, the bars have a vertical position: not less than 50 mm. When controlling a systematic way of concrete
aggregate size, this distance can be reduced to 35 mm but not less than 1.5 times the largest dimension of coarse aggregate.
In cramped conditions, allowing the bars arranged in pairs (no gaps between them). In structures with reinforced tension is tension on concrete (except for the structure to be reinforced constantly), distance waterway between the tubes placed steel must not be less than the diameter of the tube and in any event not less than 50 mm.
NOTE: The distance between the waterway ribbed rebar is taken under the nominal diameter regardless steel burrs.
8.5 Anchor Reinforced no stretch 8.5.1 For ribbed bars, as well as reinforcing bars used in the smooth circular welded steel frame and welded the ends to straight, without bending the hook. The Smooth rebar tensile used in the frame, mesh bending force should be at the top hook, hook-shaped or U-shaped L 8.5.2 The longitudinal tensile rebar and compression reinforcement should extend through the section perpendicular to the longitudinal axis structures in which they are charged with the whole intensity calculation, a smaller spaces security
l
is determined by the formula:
• • • • • •
126
dl
• • •
• • • •
RR
Security Security bs Security
(189)
TCVN 5574: 2012
•securitysecurity • dl .
but not less than Which values
•
, • • security and security • as well as the minimum allowable value security
l
security
is determined according to Table 36.
Simultaneously the bars have smooth round hook at the t op or welded with reinforced belt along the length of the anchor. That
R t b aking into account the working conditions coefficient of concrete, except
calculates the value coefficient
• b 2 . l
For concrete structures made of small particles of Group B, length security
according to the formula (189) to increase 10d
for tensile reinforcement and 5d for compression reinforcement.
Where the anchor rod should have a larger cross-sectional area required area calculations with full reliability calculated intensity, length
l
security
according to the formula (189) to allow reduced by multiplying
the ratio of the area necessary calculations and the actual area of the reinforced section. If calculated, along the anchor rod is formed by concrete cracks are pulled, then the reinforcing bars must extend into the compressible section security
l
calculated using the formula (189).
When not performing above requirements need to take measures to anchor the bars along to make sure we work with the whole intensity calculated at the section under consideration (reinforced indirectly, welded to the tip of the bar of the preset anchors or details,
l
bending folded anchor bars) while the length security not less than d
ten .
For reservation details available should consider the following features: length of anchor tensile bar of detail built into the concrete
•
buried tensile or compressive when
• security , • • security and security •
need identified by the formula (189) with values
bc
R b •
0, 75
or
•
bc
R b •
0, 25
Table 1a taken under section 36. In the
•
The remaining cases need to obtain these values under section 36. In particular Table 1b bc
the compressive stress in calves
Concrete action perpendicular anchor bar, defined as for elastic materials on the conversion section, frequent load coefficient of load
• f •
reliability
. first
When the anchor bar of the details in place under traction and slide, the right side of formula (189) is multiplied by the coefficient
•
determined by the following formula: 0, 3
• • • first Inside:
•
0, 7
(190)
NQ
security 1 security 1
N,security Q - security respectively traction and shear forces in the anchor bar. first first
At the same time anchor rod length must not be less than the minimum value security
l
outlined in this.
Smooth steel anchor group CI, AI is used only when in the first reinforced by the steel bar, or head bulge or welding rod horizontal bar short block. The length of the anchor bar is calculated under the local spit and compressed concrete. Allows use made of steel anchor hook at the top above the structural details.
8.5.3 To ensure the anchor all the bars along the edges are pulled into the pillow, in the outermost bearing freedom of bending structure must comply with the following requirements:
127
TCVN 5574: 2012
c)
6.2.3.4 If conditions are guaranteed, length of the the tensile tensile bars were pulled pulled into the pillow freedom not less than than 55 d.
d)
6.2.2.4 If conditions are not guaranteed, length of the tensile bars were pulled into the the pillow freedom freedom is is not less less than 10 10 d.
Table 36 - The coefficients for determining rebar anchor piece does not stretch
The coefficients for determining rebar anchor segment
lax Reinforced ribbed
Working conditions of reinforcement
•
lax
security
Reinforced slippery
• • security • l security , security
•
security
• • security • l security
mm
mm
not small
not small
than
than
1. The anchor reinforcement
a. Tension in concrete tensile
0.7
20
250
1.2
11
20
250
twelfth
200
0.8
8
15
200
20
250
1.55 1
11 8
20
250
15
200
15
200
b. Compressive or pulling in of concrete compressive zone
0.5
8
a. In concrete tensile
0.9
11 8
b. In concrete compressive
0.65 11
2. Connect reinforced husband
Length of anchor
security
l a t the free outer knee at which reinforced the intensity calculation is reduced
(See 5.2.2.4 and Table 23), as determined in accordance with the instructions in section 8.5.2 and Table 1b 36. When indirect
•
reinforcement, the length of the anchor is reduced by dividing the coefficients security
1 •12 • v
and reduced coefficient
• • security amount
ten • / R bb .
Inside:
• v
is the reinforcement content by volume shall be determined as follows:
+
with welded steel mesh, calculated using the formula (49), see 6.2.2.13;
+
with reinforced flex his belt, calculated using the formula:
Inside: ectional area is reinforced flex his belt placed under the edge components. A ssw
In all cases, the value
128
• v
not greater than 0.06 taken.
•
•
v A sw 2 as
,
security
for quantity
TCVN 5574: 2012
•
of concrete compressive stress on the pillow b
is determined by dividing the jet bearing for area
R.
structures and take the title of not more than 0.5 b
Reinforced indirectly distributed over the length of the anchor, from the tip structures perpendicular to the crack near the best pillow.
The length of the anchor pulled into bearing is reduced compared to the required length in that if the value security
l
Smaller 10d and taken by security
l
but not less than 5 d.I n this case as well as the
certainly the first welding rod with details available steel anchor set, the intensity calculation of the vertical reinforcement in pillow without reduction.
8.6 Arrangements for the vertical reinforcement structures
8.6.1 Sectional area vertical reinforcement in reinforced concrete structures need to take not less than the values given in Table 37.
Table 37 - Minimum Size section of longitudinal reinforcement in reinforced concrete structure, part
hundred concrete section area The minimum cross-sectional area of the vertical
Working conditions of reinforcement
reinforcement in reinforced concrete structures, the percentage area of the concrete section
1. Frame S i n bending structure, skewing the axial center outside working height restrictions of section 0.05 2. Frame S, S • Eccentric structures in the axial pull between the core S a nd 0.06
S • 3. Essence S, S • the eccentric compressive structures as:
0.05
l 0 / i <17
0.10
17 • l 0 / i • 35
0.20
35 • l 0 / i • 83
l 0 / i •
0.25
83
NOTE: Area Minimum reinforcement section for in this table are for concrete sectional area is calculated by multiplying the width of the rectangular section or the width of the belly section T (word I) with working height of section
0
hour . In reinforced structures are placed along the perimeter of the cross section as well as tensile structures reinforced chord minimum value for the above is for the whole area of the concrete section.
In structures with reinforced vertical layouts are circumferential section as well as for section tensile right center, cross-sectional area of reinforced minimum of the entire reinforced along to get double the value for the table 37.
The minimum amount of reinforcing steel S and S • i n the eccentric compressive structures that their bearing capacity corresponding to the eccentricity calculation used does not exceed 50% are taken by 0.05 does not depend on the strength of s tructures.
129
TCVN 5574: 2012
The regulations in Table 37 does not apply when selecting reinforcement sectional area when calculating components during transport and fabrication; in this case the cross section area of reinforcement is determined only by calculation according to reliability. If the calculations show that the bearing capacity of the structures lost simultaneously with the formation of cracks in the concrete tensile zone, the need to consider the requirements in 4.2.10 for structures located less reinforcement.
The provisions of this does not need to consider when determining reinforced area located along the perimeter of the panel according to the calculations or bending in the plane of the (panel).
8.6.2 Diameter reinforced longitudinal compressive structures can not exceed the value:
•
For heavy concrete, concrete granules lower level B25: ..................... 40 mm
•
For lightweight concrete, hollow concrete has granted:
•
+
B12,5 occupy ............................................. ....................... 16 mm
+
B15 to B25 from: ............................................. ..................... 25 mm
+
B30 upward ............................................... ............................ 40 mm
For concrete honeycomb has granted:
+
B10 or less ............................................... ....................... 16 mm
+
From B12,5 to B15: ........................................... .................... 20 mm
In the bending structure made from lightweight concrete reinforcement using CIV group, A-IV and lower, reinforced longitudinal diameter may not exceed:
•
For concrete from B12,5 level or lower: ..................................... ............ 16 mm
•
For concrete B15 to B25 levels from: ....................................... ............... 25 mm
•
For concrete B30 or higher level: ........................................ ..................... 32 mm rebar for higher group, the diameter of the
rebar limits must conform to the current regulations.
In the bending structure made of concrete honeycomb have B10 levels and lower, reinforced longitudinal diameter not exceeding 16 mm. Diameter reinforced compressible components along the eccentricity of pouring monolithic structure is not less than 12 mm.
8.6.3 In direct compressible structures eccentricity, the distance between the bars axis along the direction perpendicular to the plane of bending is not greater than 400 mm, also according to the bending plane - no greater than 500 mm.
130
TCVN 5574: 2012
8.6.4 In the eccentric compressive structures that their bearing capacity with a given eccentricity of axial force is used less than 50%,
/ il (for
as well as in structures with the piece
0 <1 7
example short column) which calculates not require reinforcement compressive, tensile steel and the amount not exceeding 0.3% allow no longitudinal reinforcement and transverse reinforcement (as defined in 8.6.3 , 8.7.1, 8.7.2) on the sides parallel to the plane of bending. Meanwhile, on the edge perpendicular to the plane of bending arrangement of welded steel frame, steel mesh protective concrete layer than 50 mm and not less than two times no small diameter longitudinal reinforcement.
8.6.5 In the larger beam width of 150 mm, the vertical load-bearing steel rod is pulled into the pillow not be less than 2 bar. In the slopes of the panel assembly and the beam width from 150 mm to allow drag on pillow 1 vertical bearing bars.
In the floor spacing between the bars is pulled into the pillow does not exceed 400 mm, and cross-sectional area of the bars is not less than 1/3 of the cross section of the bars in the rhythm is determined according to the largest bending moments.
In the pre-stressed porosity (pore-round) made of heavy concrete, with a height of less than 300 mm, the distance between the stress put on the knee reinforcement allows increased to 600 mm, if on a cross section perpendicular to the longitudinal axis of the torque value cracking
M i scrc determined by the formula (128), not less
More than 80% of its value due to external force torque calculation coefficient of load reliability
• f •
. first
When put to the continuous reinforced with welded mesh roll, allows bending all the bars at the bottom of the grid on top of the pillow near the intermediate segment.
The distance between the axis of the bearing bars at the mid-span and on the bearing (top bar) is not greater than 200 mm if the thickness is less than or equal to 150 mm and not greater than 1.5 hour w hen a thickness greater than 150 mm version, here hour i s the thickness. 8.6.6 In the bending structure with depth of greater than 700 mm, in the side to put the reinforced vertical structure so that the distance between them in height no greater than 400 mm and an area of not less than 0.1% of the concrete cross section size:
•
Vertical structures: the distance between the bars of this;
•
Width structures: 1/2 the width of the beam or rib, but not greater than 200 mm.
8.7 Disposition horizontal reinforcement for constructions
8.7.1 in all the structures have reinforced vertical, need to arrange reinforced belt surrounds the bars along the outer, while the distance between the bars title at each surface structures must not be greater than 600 mm and not more than twice the width of structures.
Compressive structures in reinforced eccentric stretch along the space between sections (eg, pre-stressed piles), reinforced belt may not need to set concrete only if guaranteed withstand horizontal forces. In bending structure, if the width of the side thin (width slopes equal to or less than 150 mm) only one rebar along or a welded steel frame, it allows non-reinforced belt width side there.
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In direct compressible structures eccentricity, as well as in the compressive bending structure reinforced with longitudinal compressive calculations, reinforced belt should be positioned at a distance as follows:
•
In structures made of heavy concrete, concrete granules, lightweight concrete, hollow concrete:
+
when the R
• 400 MPa: no larger than 500 mm and not more than: 15d required for
sc
steel frame; 20d for welded steel frame;
+
when the R • sc 450
MPa: no larger than 400 mm and not more than: 12d required for steel
frame; 15d for welded steel frame;
•
In structures made of concrete concrete honeycomb welded welded steel steel frame frame set: no no larger larger than 500 mm mm and and not greater than 40 40 d ( h ere d the
smallest diameter of longitudinal reinforcement under compression, in millimeters (mm)). In these structures reinforced belt to ensure a strong connection with the reinforcing bars under compression to the bars is not bulging under any direction.
At the reinforced bearing positions unfilled lapping, the gap between the belt reinforcement of eccentric compressive structures no larger than 10 d. If the content of reinforcement along compressible S • higher than 1.5%, as well as if the entire section are compressible components and total content of reinforcement S and S • greater than 3%, the distance between the belt reinforcement is not greater than 10 d and not greater than 300 mm.
The requirements of this does not apply to vertical reinforcement is arranged in a structure, if the diameter of the steel rod shall not exceed 12 mm and less than 1/2 the thickness of concrete protection. 8.7.2 In structures under compression eccentric, needs structural reinforcement belt in steel frames required so that the reinforced vertical (at least from a bar) are located on the bend of the reinforced belt and bend it apart not too 400 mm under the edge section. When the edge width of not greater than 400 mm and on each side there are not more than 4 vertical bars, which allows using a reinforced belt encircles the entire longitudinal reinforcement.
When compressive structures formed by welding flat steel frame should link them to the space frame by using the horizontal rebar spot welding with the vertical bars in the corner of the frame. Use your horizontal rebar bending machines with vertical bars at the required position in the horizontal bar welded steel frame.
If in each frame welded steel flat more reinforcement, it is necessary to use the bars horizontal bending hook to tie linking the bars along the intermediate in the frame opposite, manner a reinforcement along at least one reinforcement tied so and distance the bars does not exceed 400 mm required. Lets not put the tie bars if the edge of not more than 500 mm cross section and longitudinal reinforcement on the edge does not exceed 4 bar.
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8.7.3 In structures under eccentric compression of calculated reinforcement indirectly in the form of welded mesh (made from reinforced group CI, AI, CII, A-II, CIII, A-III with a diameter no larger than 14 mm and type bp-I) or have not stretch or helical reinf orcement rings need to obtain:
•
Grid size smaller than 45 mm is not, but not greater than 1/4 edge component section and not greater than 100 mm;
•
Diameter spiral or circle diameter of not less than 200 mm;
•
Step mesh not less than 60 mm, but not larger than 1/3 of cross section smaller edge components and not greater than 150
mm; •
Step twist or step circle of not less than 40 mm, but not larger than 1/5 diameter section components and not greater than 100
mm; •
Steel mesh, reinforced torsion (or ring) need to embrace all the bars along the bearing;
•
When tip segment reinforced compressive structures with eccentricity of welded wire mesh, should allocate not less than 4 mesh on
no less than 20 paragraphs d a djective endings if reinforced structures along the plain round bar and not less than 10
d i f reinforcement bars
along the ribbed.
8.7.4 Straight compressive structures in eccentricity, diameter steel frame reinforced belt in force should take not less than 0.25 d and not less than 5 mm, with d the diameter along the largest rebar. Diameter steel reinforced belt in the frame of the bending structure required to be taken: •
Not less than 5 mm when the depth of no greater than 800 structures mm;
•
Not less than 8 mm when the depth of 800 mm larger structures.
Correlation between horizontal rebar diameter and reinforced along the welded steel frame and welded wire mesh are determined according to the current regulations on the solder.
8.7.5 In girder structure has a height greater than 150 mm, as well as in the many voids (or similar structure multiple rib) has a height greater than 300 mm, must be horizontal reinforcement. In a special issue regardless of height, in panels with holes (or similar structure multiple rib) has a height no greater than 300 mm and in structural girder has a height less than 150 mm, allows not reinforced belts but must ensure that the requirements calculated in accordance with 6.2.2.13.
8.7.6 In structural beams and slab form mentioned in 8.7.5, the horizontal reinforcement is arranged as follows:
•
In the near pillow: an approximately 1/4 rhythm when loads evenly distributed, even when there is centralized - the distance from
pillow to pillow forces concentrated near the most, but not less than 1/4 rhythm , when the depth of structures
teps taken transverse hour ,S
reinforcement as follows:
Less than or equal to 450 mm: take no bigger hour / 2 and not greater than 150 mm. Greater than 450 mm: take no bigger hour / 3 and no greater than 500 mm.
•
On the rest of the rhythm section depth of greater than 300 mm components, reinforced belt taken steps not greater than 3/4 hour
and not greater than 500 mm.
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8.7.7 Horizontal reinforcing steel is set to shear must be anchored at both ends to make sure by welding or fastening vertical reinforcement, to ensure the durability of the links and the belt is reinforced equivalent. 8.7.8 In the compressive perforation, horizontal reinforcement in the placed with larger step hour / 3 and no greater than 200 mm, width transverse reinforcement area of not less than 1.5 hour ( w ith hour t he thickness of). Neo reinforced the need to follow the instructions in 8.7.7.
8.7.9 Horizontal reinforcement of the short coil is placed horizontally or at an angle of 45 •. Step horizontal reinforcement must not be greater than hour / 4 and no greater than 150mm (with hour h eight cantilever).
08/07/10 In bending structure simultaneously twisted, reinforced belt force should be made into the closed loop and anchored at both ends to make sure (overlap joints 30 d), also with welded steel frame all the bars horizontally in both methods should be welded to the bars along the top corner to create a closed loop, and to ensure the durability of t he links and the reinforcement belt is relatively contemporary.
8.8
Links and details of reinforced welded in place
8.8.1 Smooth and ribbed steel rod made from hot rolled steel, steel is machined heat from Group A T- I IIC and A T- I VC and ordinary steel fibers, as well as the details in place when machining need to use welding or soldering points confrontation to connect the bars to each other or connected with the steel. Allowed uses automatic arc welding or semi-automatic welding and hand following the instructions at 8.8.5.
Links confrontation of cold drawn bars type A-III B m ust be welded before pulling cool. For the bars made from hot rolled steel CIV group, A-IV (steel mark 20CrMn2Zr), AV and A-VII, reinforced, reinforced with muscle - Thermal A T- IIIC, A T- I VC, A T- I VK (steel mark 10MnSi2 and 08Mn2Si), A T- V (steel mark 20MnSi) and A T- D M only used the type of welding as defined in current standards.
Do not allow welding link of hot rolled rebar CIV group, A-IV (made from steel grade 80Si), the bars are reinforced body - Heat Group A TIV, A T- I VK (made from steel grade 25Si2P), A T- V (in addition to the kind of reinforced steel mark 20MnSi), A T- VK, A T- V I, A T- V IK and A TVII, steel fiber and cable high strength steel used as reinforcement.
8.8.2 Link type welding and welding method the bars, the details in place need to be defined taking into account the conditions of use structures, welding of steel, economic indicators - technical links and possibilities technological manufacturers.
These links form a cross by spot welding or tack welding arc to ensure that the bars of the mesh or welded steel frame to withstand the stress of not less than the intensity of its calculation (associated with reliability standards standard) need to be specified in the rebar fabrication drawings. Form cross links with the calculated reliability not be used to locate the bars during transport, or when the concrete structure manufacturing.
8.8.3 In conditions of the factory when making nets or welded steel frame or link bars along the length, use method spot welding, soldering confrontation, even when making reservation details available should use of automatic welding method for welding medication corner welding and butt-welding contact for interconnects husband.
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8.8.4 When assembling the reinforcement and reinforced concrete structural assembly, the top priority is to use the semi-automatic welding methods to ensure quality control link. 8.8.5 When there is no welding equipment necessary to allow implementation (in terms of workshops and in conditions assembly) the associated solder types Cross, welding confrontation, welding husband, welded corners to connect reinforced and details available upon reservations by the methods including arc welding by hand according to current standards and detailed reinforcement welded in place. Do not allow the use of solder attachment methods arc in the form of crosses have linked the bars bearing CIII group, A-III (made from steel 35MnSi).
When using arc welding by hand to perform the associated welding is calculated as reliability, in the mesh, welded steel frame to put the parts structure supplement in place linking the bars along and reinforced steel belt (night you, hooks, etc ..).
8.9 Connect reinforced husband does not stretch (connection required)
8.9.1 Lapping bearing no tension reinforcement are used to connect the frame, welded wire or tie rod with a diameter of no greater than 36 is connected mm. Do not use in the tensile lapping of bending structure and drag eccentric in places all be reinforced bearing capacity.
Not used lapping of the components straight that entire section tension (eg in bars stretch of the dome, bar bottom chord of the truss) as well as in all cases using reinforced group CIV, A-IV up.
8.9.2 When the bars connecting tensile and compressive as well as welded steel grid and welded steel frame according to the working length of the overlap l m ust not be less than the value
security
l
be determined by
formulas (189) and Table 36. 8.9.3 Joints welded mesh or steel frame as well as tensile reinforcement of the grid, forcing the steel frame should be staggered. Sectional area in which the bearing bars, connected at a location or within smaller segments overlap l,m ust not be greater than 50% of the total area of the tensile reinforcement for reinforced ribbed type and not greater than 25% for Plain reinforced. Connecting rods and welded wire reinforcement staggered not only allows for the structural reinforcement in the seat as well as the reinforcement used does not exceed 50%.
8.9.4 Joints welded wire mesh made from reinforced Hot Rolled Plain group CI, AI according to the bearing needs to be done so that on each grid connected in the tension on the length of the husband has no less than two rungs are welding with all vertical bar (Figure 26). Using such type of connector for the husband, seamless welded steel frame with reinforced bearing bar is located on one side and made of any kind of any steel. Grid made of welded steel CII, A-II, CIII, A-III in the bearing are performed without the need for horizontal rebar in joints in one or both grid connected (Figure 27).
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TCVN 5574: 2012
a)
d first
d
l
first
b) d ld
c) d
d first
ld first
a - when the bar is located in a plane; b, c - the horizontal bar located in different planes Figure 26 - Connect the husband (not welded) in the strength of welded mesh made from reinforced Smooth
8.9.5 Welded joints according to the non-bearing is done by lapping with paragraph husband (from between the bars of each outer bearing net): •
When the diameter of the distribution bar (horizontal bar) is not greater than 4 mm (Figure 28a, b): 50 mm
•
When greater than 4 mm (Figure 28a, b): 100 mm
When reinforced bearing diameter of not less than 16 mm, the welded steel mesh under the no bearing allows bookings confrontation and specialized wire mesh used for connection. Connecting additional mesh must cover the reinforcement placed on each side a passage not less than 15 d and not less than 100 mm (Figure 28c).
a)
d first
d
l
b) d first
d
l
a - no bar in one of the joints in grid connected; b - there is no bar in the joints in both grid connected. Figure 27 - Connect the husband (not welded) in the strength of welded wire mesh made from steel ribbed
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TCVN 5574: 2012
a)
50 • 100mm
d
t s r i f
d
b)
5 0 • 100mm
t s r i f
d
d first
• 100mm; • 15d c) 1 1
dd
t s r i f
d
a - lapping when the bearing bars are in the same plane; b - lapping when the bearing bars are in different planes; c - joints waxy mesh grid connected and supplement government.
Figure 28 - Connecting the direction reinforcement welded mesh distribution
The welded steel mesh under the bearing not allow contiguous set without overlap and do not need additional grid in the following cases: •
When placing the welded steel mesh in two perpendicular to each other;
•
When in position reinforced connecting additional structural reinforcement located under the distribution.
8:10 Joints of structural components assembly 8.10.1 When connecting structures reinforced concrete structural assembly, the internal forces are transmitted from structures to structures other through the reinforced bearing joints, using the details in place, through concrete insert in relationship connected, through the concrete wedge or (for components under compression) directly over concrete surfaces of the components are connected.
Joints pre-stressed structures, as well as the structural requirements to make waterproof cement concrete by swelling.
8.10.2 Stiff joints of the structure are assembled by chemical monolithic concrete stuffed into the joints between components. If the fabrication ensure installation fitting surfaces together (eg as head of the modules are made formwork for the first other structural), allows users joints dry when compressive force transmitted through the joints .
8.10.3 Seamless drag bearing structures need to done by: a) South details preset steel; b) South of reinforced wait;
c) Pass the pipe through the slot preset or standby components connected cables or bolts then stretching them and insert the joints with grout or concrete granules; 137
TCVN 5574: 2012
d) Paste stucco polymer components through the details link made of rebar. 8.10.4 Embedded parts should be anchored to concrete through the anchor rod or welded to reinforcement of structural forces.
Booking Details available include the anchor bar (angle or ciphertext) is soldered or welded corners husband with anchor rod made from steel usually CII, CIII A-II and A-III. Length of anchor rod of detail available when put under traction should not be less than the quantities security
l
determined in accordance with 8.5.2.
The length of the anchor bar may be reduced if the weld at the top bar of the anchor or expand the diameter anchor with not less than 2 d - for reinforcement CI group, AI, CII, A-II and not less than 3 d - Reinforced with CIII group, A-III. In that case, the anchor rod length is defined as calculated under local spit and pressed concrete and take not less than 10 d (d - anchor rod diameter, mm). If the anchor tensile are arranged perpendicular to the longitudinal axis of the construction and along them can form cracks due to the internal fundamental forces acting on the structures, then head of the anchor bar should be reinforced by the add or expand welded steel anchorages.
Details preset stamping of sheet steel is formed from the pins anchor the site adheres securely (eg in the form of anchorage sphere) and part as functional as the anchor (eg details Welding ). Embedded parts stamped from sheet steel with a thickness of 4 mm to 8 mm, is designed so that the steel is omitted when creating anchor leg is the least. Details should be calculated according to the durability of the foot of the anchor and. Reliability of every detail anchor is checked according to t he reinforced concrete calculation spit, subject to local presses. The t hickness of the details in place is determined according to the instructions in 6.2.6.3 and in accordance with the requirements of welding.
8.10.5 At the ends are connected by eccentric compressive structures (for example, at the top of the column assembled) need reinforcement indirect matching instructions in 8.7.3.
8:11 own structural requirements 8.11.1 Construction joints should be foreseen in case of building (construction) on heterogeneous ground (background taking subsidence, etc ..), at positions sudden change of load, etc .. If in the cases mentioned above, construction joints are not predictable, nails should have enough strength and rigidity to ensure the prevention of damage to the structure above, or have the special structure to achieve goals.
Construction joints, as well as thermal expansion joints in concrete structures reinforced concrete and constantly needs to be done throughout, cut nails texture until soles. Thermal expansion joints in structural reinforced concrete frame is made using pairs of slots in the middle column running down to the nail surface. The distance between construction joints, thermal expansion joints in concrete foundation and basement walls allow taking the distance between the slits of the upper structure.
8.11.2 In concrete structures reinforced to anticipate the structure: a) Why the sudden change of position size structures section; b) At the position change wall height (in smaller spaces 1m);
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c) In the concrete wall below and above the openings of each floor;
d) In the dynamic load-bearing structures; e) In addition there are smaller stress of eccentric compressive components, if the maximum stress in the cross section, defined as the objects exceeding 0.8 Elastic
b
R, even the smallest stress to less than 1 MPa
or tension, while the content of reinforcement • not less than 0.025%. The requirements in this does not apply to components of structural assemblies be tested in phase transport and assembly. In this case, need reinforcement as calculated reliability. If the calculation shows that to lose strength structures simultaneously with the appearance of cracks in the concrete tensile zone, then need to consider the requirements in 4.2.10 to put less reinforced structures (regardless the work of concrete tensile). If calculated taking into consideration the concrete tensile, see no need reinforcement and by experience also demonstrates that without reinforced during transport and assembly, when it does not need structural reinforcement.
8.11.3 Rebar installation position should be ensured in accordance with design through construction measures (set gauge plastic, concrete sealing ring made from tiny beads, etc ...)
8.11.4 Hole in the large size, panels, etc .. should be Hemmed by additional reinforcement with a cross section not smaller than the cross section reinforced bearing (under the additional reinforcement) necessary as calculated as for special i ssues.
8.11.5 When the design of the floor assembly components, should predetermined gaps between the floor and insert them in concrete. The width of the slot being defined conditions to ensure quality when inserting them and not less than 20 mm for structures with a height no greater than 250 mm and not less than 30 mm for components with a height greater than .
8.11.6 Structural components in the assembly, there should be measures to improve them: hook assembly, holes awaiting the steel pipe, fixed hook assembly made of steel bars, etc .. hook to lift must be made hot rolled steel in accordance with the requirements in 5.2.1.8.
8:12 Instructions Additional structural reinforced concrete structures prestressed
8.12.1 In pre-stressed structures, ensure adhesion between reinforcement and make concrete using reinforced ribbed, tight stuffing tubes, grooves, gaps in concrete grout or small particles. 8.12.2 Diagram and method of manufacture of prestressed structural redundancy should be selected to produce pre-stressed when not cause additional tensioning structural reduce work capacity of the structure. Layout allows joints or joints are temporary and full block of reinforced after stretching. 8.12.3 In reinforced concrete structures semi assembled, ensure adhesion structures with prestressed concrete poured in the bearing location of the structure, as well as anchor the ends of them together. In addition, the simultaneous working of horizontal structures should also be ensured by appropriate measures (set of horizontal reinforced or prestressed structures horizontally).
8.12.4 A portion of the bars along the structures may not be tensioned if they satisfy the computing requirements of the cracking and deformation.
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8.12.5 When a local reinforcement in the tensile steel anchor damage as well as in the tension device placement, should arrange the details in place or additional horizontal reinforcement, as well as increase the size of the section in this paragraph.
8.12.6 If reinforced vertical stretch is arranged in the upper and concentrate the lower, at the estimated components need additional reinforcement placed horizontal stretch or no stretch.
Transverse tensile reinforcement must be pulled before pulling force reinforcement along with no less than 15% of the entire reinforced traction in the tension along the bearing section.
Transverse tensile reinforcement should be anchored not sure by welding the preset input details. Section of the reinforcement in the structure not be calculated fatigue suffered by not less than 20% internal forces in reinforced longitudinal strain in the lower section bearing, also for texture calculated fatigue suffered - no less than 30%. Bearing section was determined by calculation according to reliability. 8.12.7 With reinforced fibers are arranged in the form of bundles of fibers, to estimate the gap between strands or between groups of fibers (by placing the steel strands wrapped spiral in bundles or place the short bar at anchor, etc. .) should have sufficient size for passing grout between the fibers in the bundle of fibers, granules or concrete filled cable slot.
8.12.8 Reinforced stress (radio or cable) in structures with pore and rib structures have to be arranged along the axis of each rib structures, except for the cases referred to in 8.6.5. 8.12.9 At the top of pre-stressed structures, need to put the additional belt reinforcement or indirect reinforcement (welded steel mesh cover all vertical rebar, reinforced belt, etc .. with step 5 cm to 10 cm) above length of not less than 0.6
p
l,e ven when the components made from lightweight concrete steps B12,5 grade B7,5 to 5 cm on the length of not less than p
l
(See 5.2.2.5) and not less than 20 cm for use core components
steel with no anchor, and anchor the structure - on the stretch by a length twice the anchor structure. Set anchor at the top of the reinforcement is required for the reinforcement being pulled out of the concrete, as well as for the reinforcement to be pulled on the pad, when not adequately adhesion to concrete (fiber smooth, cable multiple fibers), while facilities should ensure holding anchorage reinforcement in concrete at all stages of the reinforcement work.
When using high-intensity steel ribbed strand, braided cable once, reinforced bars are hot rolled ribbed reinforcing thermal processing tension on pedestal, no need to set anchor at the top of the stretch bars.
9 The required calculations and structure of reinforced concrete structures to house and major repairs construction
9.1 General principles 9.1.1 This section stipulates the design requirements of the concrete structure and reinforced concrete of buildings and structures (whether or not reinforced earlier) when major repairs.
This section provides principles existing structural calculation (calculation checks) as well as calculation and structure must be reinforced structures.
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9.1.2 Calculate check the existing structure should be carried out when there is a change of load is applied, the solution held ground and conditions of use, as well as the detection of defects and damage in structural for the purpose of determining the bearing capacity and meet the conditions of normal use of the new working conditions.
9.1.3 The structure does not meet the requirements when calculating the check need reinforcement. When designing the structure must be reinforced to stem from requests not stop or temporarily stop production.
9.1.4 Calculate check the existing structure, as well as the calculation and composition of structural reinforcement should be conducted on the basis of design documents and data on manufacturing and construction of this structure and data current status survey.
9.1.5 When there is no damage and defects reduces the bearing capacity of the structure, as well as when no deflection and expansion cracks exceeding the permitted limit, allows conducting calculations checked on the basis of design data (the geometric dimensions of the cross section of the structure, level compressive strength (pulling) of concrete, concrete grade according to compressive strength (pulling), group reinforcement, structural and structural diagrams ).
9.1.6 In case the requirements calculated in accordance with the design documentation is not satisfied or when there is no design documentation, as well as when there are defects and damage reduces the bearing capacity of the structure, when sag or expansion cracks exceeding the permitted limits, it is necessary to conduct test calculations have t o mention the structural survey data exist.
9.1.7 Current status survey should provide data on the geometric dimensions of the section, the layout reinforcement in structures structural strength of concrete and steel, the deflection of the structure and the width of the crack, the defects and damage, load, calculate the static diagram of the structure.
9.1.8 The structural reinforcement need only consider the case when the existing structure does not satisfy the requirements as calculated check the bearing capacity or the conditions required for normal use. No need structural reinforcement if:
•
The actual deflection of the structure exceeds the permitted limit (see 4.2.11) but does not affect the normal use requirements
and does not change its structure diagram; •
Structural there are deviations from the requirements listed in Section 5, but the survey did not detect any damage caused by
deviations that although the texture was used for a long time.
9.1.9 The calculation and composition of structural reinforcement need to be done on the basis of the current status survey data requested in 9.1.7.
9.2 Calculation of check 9.2.1 Calculate test concrete structures and reinforced concrete to comply with the requirements stated in sections 4 to 8, and in this section. 9.2.2 No need to calculate according to the state second limit if such displacement and width of cracks in the existing structure is smaller than the allowed limit, while the internal forces in the section components generated by the load does not exceed force value by the actual load acting on the structure.
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9.2.3 When calculating the required check cross section of the structure has defects and damage, as well as to check the section in which, in the course of the survey findings are areas of concrete with lesser intensity intensity the average level of 20% or more. The mention the defects and damage are shown in the calculation by reducing the cross section area of concrete or reinforced. Also need to mention the influence of the defects and damage to the characteristics of strength and deformation of concrete; to the eccentricity of axial force; the cohesiveness of concrete and rebar, etc ..
9.2.4 The characteristic calculation is determined according to Section 5 depending on the level convention compressive strength of the concrete in existing structures.
9.2.5 When calculating the test according to the design documents, in case if structural design existing provisions of the standard features of the concrete is grade according to its intensity, the level of compressive strength convention of concrete to be taken as follows:
•
For heavy concrete, concrete granules, lightweight concrete: get 80% intensity standard cubic samples corresponding label
under compressive strength. •
For concrete honeycomb: get 70% intensity standard cubic samples corresponding label under compressive strength.
For the value-level convention compressive strength of the concrete is different from the value mentioned in 5.1.1.3, calculate the intensity of the concrete was determined by linear interpolation.
9.2.6 When calculating the test based on the current state of the survey results, the value of compressive strength level convention of concrete is determined according to 9.2.5, but instead of concrete by the actual intensity value of concrete under group structure, individual structures, or in its region, resulting from the current state of the survey results, according to the method of non-destructive testing, or test methods sample taken directly from the structure.
9.2.7 Depending on the condition of the concrete, steel structures and working conditions thereof, as well as, depending on the method of determining the strength of concrete, when an ad hoc basis may use other methods to determine the intensity the concrete.
9.2.8 The characteristics of the reinforcement calculation is determined depending on the group of steel used in reinforced concrete structures exist as directed in part 2 i nclude the requirements set out in 9.2.9 and 2.9.10. 9.2.9 When performing test calculations under the existing structural design documents based on the old standard, the intensity of the reinforced
R d etermined under section 5. Then the intensity of steel fiber standards
standards SN
BI group earned 390 MPa. Calculated tensile strength of reinforcement
S
R i s determined by the formula:
•
RR
• s
sn s
Inside S •
•
is the coefficient of reliability of reinforced, taken as follows;
When calculated according to the first limit state: + 142
For reinforcement bar group
TCVN 5574: 2012
CI, AI, CII, A-II, CIII, A-III: .................................. ... 1.15 CIV, A-IV, AV and A-VI: ...................................... .... 1.25 +
For steel fiber group BI, B-II, Bp-II, K-7, K-19: ................................ ....... 1.25 Bp-I: .................................... ................................... 1.15
•
When calculated according to the second limit state: ............................. 1.00. Tensile strength calculations
R O K sw
horizontal reinforcement (reinforced belt and the oblique bars) determined by multiplying the calculated intensity values
• si (value
R obtained with a coefficient of working conditions
S
• si for in section 5). Compressive strength of reinforced calculations sc
III B) d egree calculated tensile strength of reinforcement
R,b ut not greater than the value stated in the
S
section 5. For Groups A-III steel B, c ompressive strength calculations
R ( e xcept group reinforced A-
sc
R taken as required by section 5.
Also, it should mention the coefficient of working conditions additional reinforcement under 5.2.2.4. The value of the intensity of reinforcement calculations are rounded to three significant digits.
02/09/10 When calculating test-test results form the reinforcement taken from the current status survey, the intensity of the standard of rebar are taken by the average value of the yield practical (or yield specifications) obtained from reinforced model experiments and divide coefficient:
•
for reinforced reinforced CI CI group, group, AI, CII, A-II, CIII, CIII, A-III, A-III B, CIV, A-IV: ..................... 1.1
•
reinforcement for other groups: .......................................... ................................ 1.2 intensity of reinforcement
calculations should take under the requirements stated in 9.2.9.
09/02/11 Depending on the number of samples and the status of the reinforcement, the basis can certainly use other methods to determine the intensity of reinforcement calculations. 09/02/12 When no document design and could not get the sample, enables taking calculated tensile strength of reinforcement S R depending on the type of steel:
•
For reinforcement Smooth: grab S
•
For reinforced ribbed run: + 1 side: take S
45 MPa; R = 2
+ 2 sides: take S
95 MPa. R = 2
R = 155 MPa;
Meanwhile intensity value calculation of compression reinforcement degree S horizontal steel
sw
et certification R g
0, 8
R,a lso the intensity of the aggregate calculation
R S .
9.3 Calculation and texture structures have reinforced 9.3.1 The requirements of this section used to design and calculation of reinforced concrete structures, reinforced with roll-formed steel, concrete and reinforced concrete. 143
TCVN 5574: 2012
The structure of reinforced concrete reinforced should be designed to satisfy the requirements outlined in section 4 and section 8 of the standard TCXDVN 338: 2005 (when the reinforced steel roll-formed) and the provisions of section this.
9.3.2 When designing reinforced concrete structural reinforcement, should ensure simultaneous working conditions between the reinforcement and the structure must be reinforced.
9.3.3 Reinforced structural calculations should be carried out in two stages: a)
Before the reinforcement work: calculate weight loads due to structural reinforcement (only calculated according to the first limit
state); b)
As the reinforcement work: calculations bear the entire load used (calculated according to both limit state).
Calculated according to the status of second limit may not be done if the load use increased, hardness and resistance to cracking of the structure satisfies the requirements of the conditions of use, which reinforced because reasons detected defects and damage.
9.3.4 For structures damaged (destruction of at least 50% of the cross section of concrete or at least 50% of the cross section reinforced), to calculate structural reinforcement bear the entire load is applied (not to mention the structural work must be strengthened).
9.3.5 Cross sectional area of the structure must be reinforced should be determined based on the actual weakness due to corrosion of it. Steel fiber reinforced high strength calculations regardless of the stain or corrode the internal corrosion, and erosion caused by ion
Cl.
•
9.3.6 Intensity intensity standards and calculation of reinforced steel structures taken as prescribed in TCXDVN 338: 2005.
Intensity and intensity standard calculations and reinforced concrete structures of reinforced concrete must be reinforced and the reinforced section should take as directed in Section 2 and under 9.2.4 to 2.9.12. 9.3.7 When designing the structure must be reinforced, in principle, it should be noted to the load during reinforcement should not exceed 65% of load calculations. When too complicated or impossible to reduce the load to the required level, which allows conducting reinforcement in a state of load-bearing structures larger. Then calculate the characteristics of the concrete and reinforcement steel must be multiplied by the coefficient of working conditions of concrete is
• br first= 0.9 and the reinforcement of the
• sr first= 0.9.
In any case, the level of the load off the structure must be reinforced to be selected according to the conditions to ensure the safety of the process of reinforcement work. 9.3.8 In case, if the structural reinforcement system turned into super static, it is necessary to mention the factors mentioned in 4.2.6.
9.3.9 Value prestressing
sp
•
• • and sp
in the reinforcement steel S and S • n eed to be taken in accordance with 4.3.1 and
4.3.2. In this case, the value of the largest prestressed reinforcement 0, 9 R,
144
ser s
for bars and
0, 7 R,
ser s
sp
for steel fibers.
•
• • and sp
take not exceed:
TCVN 5574: 2012
The minimum value of prestressing reinforcement in taking not less than
0, 49
R,
ser s
.
09/03/10 When calculating these components must be reinforced by steel bars prestressing, losses stress should be determined in accordance with 4.3.3 and 4.3.4. When determining losses due to deformation of the anchoring device placed near the stretch, should mention the distortion caused by compression stress pedestal. When there is no empirical data, get that distortion value by 4 mm.
03/09/11 Coefficient of precision tension should be determined according to 4.3.5 by introducing additional coefficients
• sp
depending on the specific structural reinforcement as follows:
•
For horizontal bracing and reinforcement bar pull: ......................... 0.85
•
For reinforced belts and rod skewers: ........................................ ................ 0.75
03/09/12 For bending structure and eccentric compression reinforced concrete and reinforced concrete, the calculation is done as for structural sections special conditions to comply with the requirements of computational and structural created to ensure the work simultaneously between the old concrete and new concrete. Meanwhile the irreparable damage and defects of structures must be reinforced (rebar corrosion or broken; corrosion; layered and damaged concrete, etc ..) to reduce bearing capacity of the components that should be included in the calculation as in computational structural test before reinforcement.
09/03/13 When the structures are reinforced concrete or reinforced concrete with concrete and reinforced with all levels of reliability different, the strength value calculation of concrete and reinforced taken into account under the durable intensity of their calculations.
03/09/14 For structures of reinforced concrete, reinforced with concrete, reinforcing steel and reinforced concrete, the calculation should be done under conditions of reliability for the section perpendicular to the longitudinal axis components, for section tilt and profile space (in case of a torque effect), as well as the calculation subjected to local loads (compressors, compressed puncture, tear) according to the requirements of section 6 and mention available types and reinforced concrete with different strength levels in the structures to reinforce.
03/09/15 Need to calculate the reinforced concrete structure, reinforced with concrete, reinforced concrete or conditional forms, extended and closed cracks; Conditional deformation satisfies the requirements of section 7 and the additional requirements related to deformation and stresses in structures of reinforced concrete before putting Strength at work, as well as concerning the exist concrete and reinforced with different reliability levels in the structures to reinforce.
09/03/16 The calculation of structures of reinforced concrete, reinforced with rebar prestressed no adhesion is done according to the limit state the first and second according to the requirements of section 7, section 8 and require additional supplementing the request no adhesion between concrete and rebar. 03/09/17 The smallest size of the section component, reinforced with concrete and reinforced concrete should be determined on the basis of calculation under the internal forces taking into account the technological requirements and not smaller than the size in the requirement in section 8 of the distribution and thickness of reinforced concrete.
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03/09/18 Level compressive strength of concrete reinforced concrete required degree of structural reinforced and not less than B15 for structures above and B12,5 for nails. 03/09/19 In these cases, when the reinforcement is contemplated after offloading for structural reinforcement must only be loaded when reinforced concrete designed to achieve sufficient strength. 09/03/20 When reinforced with concrete and reinforced concrete poured in place to have the solution (cleaning, surface texture textured reinforced, etc ..) to ensure the strength of the connections (joints) and the work simultaneously between the structural reinforcement and reinforced.
03/09/21 When reinforced by length only locally damaged areas, to conduct further reinforce the damaged portion not contiguous within a length not more than 500 mm and not smaller smaller: •
5 times the thickness of reinforced concrete;
•
length along the reinforced steel concrete joints;
•
2 times larger than the cross section reinforced structures (for structural rods).
09/03/22 Allows conducting reinforcement structures using reinforced not stretch while structural loads by welding reinforcement steel in reinforced existing if under the effect of the load during reinforcement, to ensure durability of section reinforced structures, not to mention the work of the reinforcement steel. Link welding points are distributed at a distance not less than 20 d along rebar.
146
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Appendix A (Regulations)
Concrete for concrete structures and reinforced concrete
A.1 formula to determine the compressive strength level (pull) of concrete The correlation between level compressive strength and compressive strength of concrete instant is determined by the for mula:
• • BB m
• 1 1, sixty • • four
(A.1)
Correlation between tensile stiffness and tensile strength of concrete instant is determined by the formula:
• • BB mt t
• 1 1, sixty • • four
(A.2)
In the formula (A.1) and (A.2):
B,m MT B
respectively the statistical average value of compressive strength and tensile instant, defined as follows:
•m ,1
here: ,1
2
2
mt
••
n B•n2 B 1 1 n BB 2
•1
2
• .. . •
B
nn
(A.3)
• .. . • nnn n
, .. . , nnn is the number of standard sample corresponding intensity of compression (pulling) is n
, .. . , BBB ; n
.135 with • the coefficient of variation of intensity of a standard sample, depending on the level of concrete production technology: • = 0 compressible case, • = 0 .165 cases with tension.
A.2 Correlation between levels of concrete durability and strength of concrete under Table A.1 - Correlation between grade compressive strength of concrete and
of concrete under compressive strength
Compressive strength level
The average intensity of the test sample Standard, MPa
Bituminous under compressive
Compressive strength level
The average intensity of the test sample standard, MPa
strength
Bituminous under compressive strength
B3,5
4.50
M50
B35
44.95
M450
B5
6.42
M75
B40
51.37
M500
B7,5
9.63
M100
B45
57.80
M600
B10
12.84
M150
B50
64.22
M700
B12,5
16.05
M150
B55
70.64
M700
B15
19.27
M200
B60
77.06
M800
B20
25.69
M250
B65
83.48
M900
B22,5
28.90
M300
B70
89.90
M900
B25
32.11
M350
B75
96.33
M1000
B27,5
35.32
M350
B80
102.75
M1000
B30
38.53
M400
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TCVN 5574: 2012
Table A.2 - Correlation between tensile strength grade of concrete and
of concrete under tensile strength Tensile strength
Mark intensity
The average intensity of the standard sample
MPa
level
tensile
B t 0 0.4 .4
0.55
-
B t 0 0.8 .8
1.10
K10
B t 1 1.2 .2
1.65
K15
B t 1 1.6 .6
2.19
K20
B t 2 2.0 .0
2.74
K25
B t 2 2.4 .4
3.29
K30
B t 2 2.8 .8
3.84
K35
B t 3 3.2 .2
4.39
K40
B t 3 3.6 .6
4.94
-
B t 4 4.0 .0
5.48
-
NOTE A.1 and A.2 in the table: NOTE 1: The value of concrete under compressive strength (pull) have been rounded to the nearest value, but prone to safety.
NOTE 2: The values stated in the table apply to heavy concrete, concrete granules, lightweight concrete, hollow concrete.
A.3 Correlation between compressive strength of concrete standards
bn
R ( i ntensity mausoleum
pillar) and the level of the compressive strength of concrete
The correlation between the compressive strength of concrete criteria (intensity prismatic) and level compressive strength of concrete is determined according to the following formula:
+ For heavy concrete, concrete granules, lightweight concrete and hollow concrete:
bn
BR • • , 0 • 0 77, 001 B •
(A.4)
bn
BR • • , 0 • 0 95, 005 B •
(A.5)
but not less than 0.72. + For concrete honeycomb:
Value
148
R c bn alculated using the formula (A.4) and (A.5) is given in Table 12 of this standard and have been rounded.
TCVN 5574: 2012
Appendix B
(Refer) Some common types of steel and manuals B.1 Classification according to limit steel of some steel melt Table B.1 - The type of steel is often Yield refers The group
Designs
conversion type steel Pictures section
Hot-rolled
round
carbon steel
Bars
to converted
Symbol steel
Water production and
Limit strength
production standards
Mpa
MPa 235
CI AI
Vietnam (TCVN 1651: 1985)
235 min. 380 min.
Russia (GOST 5781-82 *)
SR235 250
BS 4449: 1997 gr.250
Japanese (JIS G 3112 -1991)
235 min.
380 • 520
British (BS 4449: 1997)
250 min.
287.5 min.
AS 1302-250R AS 1302-250S
Zebra
Yield MPa
250 min.
-
250 min.
-
Australia (AS 1302-1991)
295
SR295
Japanese (JIS G 3112 -1991)
295 min.
380 • 520
295
SD295A
Japanese (JIS G 3112 -1991)
295 min.
440 • 600
SD295B
Japanese (JIS G 3112 -1991)
(ribbed)
300
CII A-II
d l e i y l a u t c a e h t o t g n i d r o c c A
Vietnam (TCVN 1651: 1985)
295 • 390 440 • 600 300 min. 500 min.
Russia (GOST 5781-82 *)
300
ASTM A615M gr. 300
335
RL335
345
SD345
Japanese (JIS G 3112 -1991)
345 • 440 490 min.
390
SD390
Japanese (JIS G 3112 -1991)
390 • 510 560 min.
390
CIII A-III
400
AS 1302-400Y
420
ASTM A615M gr. 420
460
BS 4449: 1997 gr.460A
American (ASTM A615M-96a)
Chinese (GB 1499-91)
Vietnam (TCVN 1651: 1985)
300 min.
335 • 460 510 min.
390 min. 600 min.
Russia (GOST 5781-82 *) Australia (AS 1302-1991)
American (ASTM A615M-96a)
British (BS 4449: 1997)
400 min.
SD490
520
ASTM A615M gr. 520
540
A-III B
540
RL540
-
420 min.
620 min.
460 min.
483 min.
BS 4449: 1997 gr.460B 490
500 min.
497 min.
Japanese (JIS G 3112 -1991)
American (ASTM A615M-96a) Russia (GOST 5781-82 *)
Chinese (GB 1499-91)
490 • 625 620 min. 520 min. 540 min. 540 min.
690 min.
- 835 min.
NOTE: The steel sign mentioned in this list includes only original characters speak mechanical properties, do not write the character tail speak other characteristics. Symbol full view of the corresponding standards of each country.
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TCVN 5574: 2012
Table B.2 - The type of high strength steel Yield refers to The group
Designs
conversion type steel Pictures section
Hot-rolled
zebra
carbon steel (bar)
steel fibers
Type 1
t i m i l d i u q i l l a n o i t n e v n o c e h t o t g n i d r o c c A
7 types of fiber
150
Symbol steel
Water production and
Yield MPa
Limit strength
production standards
Mpa
MPa 590
RL590
590
CIV A-IV
fibers
fiber
converted
785
SBPR 785/1030
788
AV
830
ASTM A722M gr.1035
835
RE (RR) -1030
930
SBPR 930/1080
930
SBPR 930/1180
980
A-VI
Chinese (GB 1499-91) Vietnam (TCVN1651: 1985)
590 min.
885 min.
590 min. 900 min.
Russia (GOST 5781-82 *) Japanese (JIS G 3109-1994)
785 min.
1030 min.
Russia (GOST 5781-82 *)
788 min.
1000 min.
830 min.
1035 min.
835 min.
1030 min.
Japanese (JIS G 3109 -1994)
930 min.
1080 min.
Japanese (JIS G 3109 -1994)
930 min.
1180 min.
Russia (GOST 5781-82 *)
980 min.
1250 min.
American (ASTM A722M-98) British (BS 4486: 1980)
SBPR 1080 1080/1230
Japanese (JIS G 3109-1994)
1080 min. 1230 min.
1175 A T- VII
Russia (GOST 10884-94)
1175 min. 1400 min.
1300
wire - 1570-7 wire -
British (BS 5896: 1980)
1300 min.
1570 min.
1390 min.
1670 min.
1390
1670-7
1390
wire - 1670-6 wire -
1390 min.
1670 min.
1470
1770-6
1470 min.
1770 min.
1390
wire - 1670-5 wire -
1390 min.
1670 min.
1470
1770-5
1470 min.
1770 min.
Wire 1350 - 1620 - 4.5
1350 min. 1620 min.
1390
wire - 1670-4 wire -
1390 min.
1670 min.
1470
1770-4
1470 min.
1770 min.
1200
3Bp1200
1200 min. 1470 min.
1300
4Bp1300
1300 min. 1570 min.
1400
5Bp1400
1400
6Bp1400
1400
7Bp1400
1400 min. 1670 min.
1500
8Bp1500
1500 min. 1780 min.
1420
7-wire standard-1670-15.2
Russia (GOST 7348-81 *)
British (BS 5896: 1980)
1400 min. 1670 min. 1400 min. 1670 min.
1420 min. 1670 min.
1500
7-wire standard-1770-12.5
1490
7-wire standard -11 -1770
1490 min. 1770 min.
1500
-1770 standard 7-wire - 9.3
1500 min. 1770 min.
1550
7-wire super -1770 - 15.7
1550 min. 1770 min.
1580
7-wire super -1860 - 12.9
1580 min. 1860 min.
1570
7-wire super -1860 - 1.3
1570 min. 1860 min.
1580
7-wire super -1860 - 9.6
1580 min. 1860 min.
1550
7-wire super -1860 - 8.0
1550 min. 1860 min.
1450
7-wire drawn -1700 - 8.0
1450 min. 1700 min.
1550
7-wire drawn -1820 - 5.2
1550 min. 1820 min.
1560
7-wire drawn -1860 - 2.7
1560 min. 1860 min.
1500 min. 1770 min.
TCVN 5574: 2012
Table B.2 - ( finish) Yield used to convert
The group
Designs
conversion type steel Pictures section
fiber
e h t o t g n i d r o c c A
t i m i l d i u q i l l a n o i t n e v n o c
7 types of fiber
Type 19 yarn
Symbol
MPa
1400
Yield MPa
Water production and
steel
Limit strength
production standards
K7-1400
Mpa
1400 min. 1670 min. Russia (GOST 13840-81)
1500
K7-1500
1500 min. 1770 min.
1550
ASTM A416M gr. 1725
American (ASTM A416M-98)
1550 min. 1725min.
1670
ASTM A416M gr. 1860
American (ASTM A416M-98)
1670 min. 1860min.
1500
K19-1500
Russia (TU 14-4-22-71)
1500 min. 1770 min.
NOTE: The steel sign mentioned in this list includes only original characters speak mechanical properties, do not write the character tail speak other characteristics (some symbols have added sugar, for example 7- wire super -1860 - 12.9). Symbol full view of the corresponding standards of each country.
B.2 method of converting steel equivalent B.2.1 When using other kinds of steel with steel according to ISO (or Russian GOST) must be based on the corresponding standards of steels which require the use of steel in construction. Meanwhile, it is necessary to know the main technical indicators outlined in 5.2.1.1 (Chemical composition and manufacturing methods to meet the requirements of the steel used in construction; the criteria for intensity: the liquid limit, limited durability and coefficient of variation of those limits; modulus recovery, elongation extreme, ductility, weldability is; change the mechanical properties while increasing the temperature drop for structural resistance to high temperature or low limit fatigue of structural loads repeat ...). In addition, the need to know the shape of cross section: circular smooth type or striping (ribbed), steel fiber or cable.
To be able to convert all kinds of steel of equivalent type, steels are classified into two groups: those with actual yield clear and limited group practically no clear flow. For steel with yield fact not clear, based on the conventional liquid limit prescribed in the relevant standards as a basis for conversion.
B.2.2 When using other kinds of steel with steel according to ISO (or GOST Russian), to be based on the value of yield practical (or limit flow convention) for conversion of steel nearest equivalent but prone to security whole.
B.3 Application of the coefficient calculation
B.3.1 When applying the calculation coefficient for steels not TCVN or (GOST Russian), to be taken as directed after each factor:
B.3.1.1 Coefficient of reliability of reinforced S
•
When calculated according to the first limit state For steels with yield and value greater than 300 MPa include: grab
• = 1.1;
S
For other types of steel only conventional liquid limit and that value is greater than 600 MPa: grab
S
• = 1.2;
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TCVN 5574: 2012
•
For steels with yield and value in the range of 300 to 600 MPa: grab S
per
linear interpolation between the two values of 1.1 and 1.2.
When calculated according to the status of second limit Pick S •
= 1.0.
•
B.3.1.2 The coefficients of working conditions si
When calculated according to the first limit state a) Coefficient
• S 3 are included when loop load-bearing structures. Not permit application of the value
• S 3
write the
in Table 24 for other types of reinforcing steel with reinforced types in this table. In case of using other types of reinforcement should know their fatigue limit. b) Coefficient
• S 4 are included when loop load-bearing structures and welded reinforced links.
c) Coefficient
• S 6 be mentioned as high-strength steel reinforced (limited flow convention) working in
higher event limits conventional flow (see 6.2.2.4) to determine
• S 6 in formula (27), coefficient •
be obtained as follows:
+ For other types of steel cable: • = 1 .15; + For bar steel steel with with aa tensile strength of 590 MPa MPa standards by: by: • = 1 .20; + For bar steel steel with with aa tensile strength of 800 MPa MPa standards by: by: • = 1 .15; + For bar steel steel with with aa tensile strength greater than 1000 standards MPa: MPa: • = 1 .10; + For bar steel steel with with a tensile strength strength standards falling between between on • taken according to linear interpolation.
When solder joints located in the components have reached the bending moment
, 90 M max ( max
M
the torque
• S 6 for reinforcement with conventional liquid limit is less than 800
calculate the largest), coefficient values
No greater than 1.1 MPa taken; for reinforcement with conventional liquid limit greater than 1000 MPa take no greater than
1000
1.05; if the limit value is in the range of 800 MPa flowing to
MPa he took no greater than the value • according to linear interpolation corresponding values of conventional liquid limit.
d) Coefficient 7
• S
degree 0.8 for type Smooth steel reinforcement using horizontal components made from lightweight concrete
B7,5 and lower levels (see Table 15); When calculated according to the status of second limit
Intensity of reinforcement calculation when calculated according t o the status of second limit Accounting coefficient of working conditions si
B.3.1.3 Value
152
•
SR
•
= 1.0.
R,
ser s
taken into
TCVN 5574: 2012
•
In formula (25) value
SR
is determined depending on the type of steel (limited actual flow or
Conventional liquid limit and steel cables form):
•
+ for steels with actual flow limit (usually steel bars and fiber):
•
+ for steels with conventional liquid limit: he took
•SR R
s
• 400 • •
sp
•
SR
R• •
sp s
• • • sp (With steel fibers and cables
• • sp • 0 ); •
When using both stretch and non-stretch reinforced the
SR
•
tensile strength limits vary lets get value B.3.1.4 Value
determined by the tension reinforcement. When using reinforced
SR
The most reliable values that limit.
• • spi and • in 6.2.2.19
When the cause for all kinds of prestressed reinforcement bars with conventional liquid limit by mechanical methods, as well as auto-thermal method or methods of thermal engine automatically: •
• • spi •
• •
spi
R si • 0,
spi
R si
0•5
•1200 1500• 0
,
• 0 4, 8
When causing tensioned for the type of reinforcement bars with liquid limit convention with other methods, as well as causing tensioned for reinforcement fiber and cable liquid limit conventional by any means, get price treatment
• • spi B.3.1.5 Value
= 0 and coefficients • = 0.8.
• r • r
In formula (45)
taken as follows:
• r = 1.0;
+ For a limited flows reinforced the fact:
• r = 1.1.
+ For reinforced with conventional liquid limit (including rebar, steel fiber, cable):
B.3.1.6 Coefficient • a nd • i n formula (55) Coefficient • g rab bars by 25 for high-intensity conventional liquid limit. Value • t ake not less than 1.0 and no greater than 1.6.
B.3.1.7 Value
•
sc,u
In formula (57) with respect to the type of reinforcement may yield greater than 800 MPa convention, 1200 MPa not greater than, the flow limit of 800 MPa smaller convention
• b 2 , • b 3
B.3.1.8 Coefficients
and
•
sc,u
• b
sc,u
pick
no greater than 900 MPa taken.
• b 4
In 6.2.2.3: When calculating structural reinforcement used along with conventional liquid limit, the coefficients
• b 3 as 4
•
• b 2 ,
(6.2.3.4) should be multiplied by 0.8.
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TCVN 5574: 2012
B.4 Requirements structure
B.4.1 Thickness of concrete protection
B.4.1.1 In 8.3.4: Thickness of protective concrete at the tip of the pre-stressed structures along the length of the communication stresses (see 5.2.2.5) should be taken not less than: For bars (intense) with conventional liquid limit: ..................... 3 d For reinforced cable types: ........................................... ................................. 2 d (here, d measured in millimeters (mm)).
In addition, the thickness of concrete protection in areas mentioned above must not be less than 40 mm for all types of reinforcing steel bar and not less than 30 mm for reinforced cable format.
B.4.1.2 In 8.6.2: In the bending structure made from lightweight concrete reinforcement using equivalent CIV, A-IV and lower, reinforced longitudinal diameter may not exceed: For concrete compressive strength level from B12,5 or less: .................. 16 mm for concrete with compressive strength level from B15, B25: ............................ 25 mm for concrete compressive strength levels of B30 or more: ... ....................... 32 mm rebar for higher group, the diameter of the rebar limits must conform to the corresponding provisions current.
B.5 Regulation on solder reinforcement
When welding reinforcement must comply with the requirements of welded reinforced by the standards corresponding to each kind of steel is selected: type welding, welding methods ...
B.6 Regulations reinforced connections
Must comply with the requirements of section 8 of this standard.
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TCVN 5574: 2012
Appendix C
(Regulations)
Deflection and displacement of structures
C.1 Scope of Application C.1.1 This section specifies the limit values for deflections and displacement of the bearing structure and covering of houses and buildings when calculated according to the status of second limit.
C.1.2 The provisions of this section do not apply to hydraulic works, transport, nuclear power plant as well as the columns of the transmission lines, the distribution device outdoors and the antenna of the communication work contact.
C.2 General Directions C.2.1 When calculating the structures built in the deflection (camber) or displacements must satisfy the following conditions:
• ffu
(C.1)
Inside:
f
the deflection (camber) or displacement of parts of the structure (or the entire structure) was determined taking into account the factors that affect their value as in C.7.1 to C.7.3;
f u
the deflection (camber) or displacement limits specified in this section.
The calculation should be done comes from the following requirements:
a)
Technological requirements (to ensure normal conditions of use of technological devices, lifting devices, measuring instruments
and inspection etc ..); b)
The structural requirements (to ensure the integrity of the structure adjacent to each other and their joints, to ensure the tilt
regulation); c)
The psychological and physical requirements (prevention of harmful effects and feeling uncomfortable when structural oscillations);
d)
The requirements for aesthetics and psychology (ensuring good impression on the external appearance of the structure, eliminating the sense
of danger).
Once calculated, each request should be met on a separate non-interdependent. The limitations of structural oscillations should be regulated according to the requirements stated in C.7.4. C.2.2 Situations in which calculations necessary to determine deflections, displacements and loads corresponding to them, as well as the requirements relating to initial camber in C.7.5.
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TCVN 5574: 2012
C.2.3 Deflection limits of the structural roof and floor are regulated by the requirements of technological, structural and psychophysiology should be calculated from the rollers of the components corresponding to the state at the time of loading caused deflection should take into account, and follow the requirements of aesthetics and psychology is calculated from the straight line connecting the bearing of structures (see C.7.7).
C.2.4 Deflection of the structural parts according to the aesthetic requirements and psychology without restriction if they are hidden do not see, or did not worsen the appearance of texture (eg texture wing bar lowered suspension or advanced, thin roof, eaves tilt). Deflection according to the requirements mentioned above also do not have restrictions on the structural floor and roof above the room had frequented during ephemeral (such as transformers and attic)
NOTE. For all types of roof deck integrity layer roof needs to be guaranteed as prescribed by the methods of composition (eg, using the structure of clearing, or giving the roof structure to work in primary continuous map).
C.2.5 Coefficient of reliability of the load for all load and motivation factor for load trucks, electric trucks, crane is taken by 1.
C.2.6 For detailed structural buildings and structures that deflections and displacement thereof is not mentioned in this standard and other standards, the deflection vertically and horizontally due to load frequently, temporary long short-term and temporary, should not exceed 1/75 1/150 span or cantilever length.
C.3 The limit vertical deflection of structures C.3.1 Vertical deflection of structures and corresponding load deflection used to determine which are given in Table C.1. The requirements for the gap between the components outlined in C.7.6.
Table C.1 - The limit vertical deflection u
f and corresponding load to determine
vertical deflection Load to determine the
According to the requirementsDeflection limit under
Structures texture
demand
vertically u
f
vertical deflection
1. beam hanging crane and the crane is controlled:
-
Technology
50 l / 2
Due to a crane
1K-6K group
00 l / 4
As above
7K group
00 l / 5
As above
8K group
00 l / 6
As above
from the floor, including pulley
- from the cabin to the work mode:
156
Psychophysiology and technology
TCVN 5574: 2012
Table C.1 - ( next) Sag vertical limit
Loads to determine sag under the
According to the requirements
Structures texture demand
stand
f u
Regular and long-term temporary
2. Make, scaffolding, beams, copy, beam, plate (including broken ribs and copy):
a. Roofs and floors visible with the
Aesthetic - Psychological
aperture l:
l less than or equal 1 m
l / 120
l by 3 m
l / 150
l 6 m
l / 200
l by 24 (12) m
l / 250
l greater or equal to 36 (24) m
l / 300
b. Floor roof and floors between
Structure
Get under C.7.6
floors with walls below
Reduce the gap between the bearing parts of the structure, and the walls
c. Floor roof and floors between floors
50 l / 1
Structure
Effects after completing the walls, floor and strut class
when we have the details on affected separation (bracing, laminated flooring, partitions)
d. Floor roof and floors between floors when the hoist, crane hanging controlled from: + floor
Technology
Smaller value of the two
Temporary load can mention loads by
values l / 3 00 or
crane or hoist 1 on 1 rails
a / 150 + cabin
Psychophysiology smaller value
Load by crane or hoist 1 on 1 rails
of two values: l / 4 00 or a / 2 00
e. The floor is affected by:
Psychophysiology and technology
- the shifting of loads, materials,
50 l / 3
Value disadvantage in two weight
parts and details of machinery and
values:
other mobile loads (including
+ 70% of all temporary load
background downloading not moving
standards
on rails)
+ the load of a vehicle loading
- moving on rails download: + narrow
00 l / 4
Load of a wagon that runs on a rail
+
00 l / 5
As above
large format
157
TCVN 5574: 2012
Table C.1 - ( finish) According to
Structures texture
Loads to determine
Deflection limit under
requirements
deflections under
f
vertically u
vertically
3. Elements of stairs (the stairs, landings, referring to children) balcony, loggia
Beauty -
As Section 2a
mentality
Identified as requiring C.3.4
biopsychosocial physical
4. The slab, the staircase, landing, referred to, which of them do not sag obstructing adjacent
biopsychosocial
0.7 mm
1 kN concentrated load at midspan
l / 2 00
Reduce the gap between the bearing
physical
parts 5. lintel, wall panels on the windows and doors
Structure
(beams and purlins of glass walls)
component and insertion of windows and doors under constructions
Beauty -
As in Section 2a
mentality
Symbols in the table:
l t he pace of structural calculations.
a or truss girder is associated with cell lines of cranes hanging. NOTE 1: For the coil l taken by themselves twice the length of the coil. NOTE 2: For intermediate values of l in Section 2a, the critical deflections determined by linear interpolation taking into account the requirements in C.7.7
NOTE 3: In section 2a number in parenthesis () are taken to a room to 6 m height. NOTE 4: Features calculate sag under Section 2d outlined in C.7.8. NOTE 5: When taking deflections limited to aesthetic requirements and allows length psychological rhythm
l taken the distance between the inner surface of the
bearing wall (or column).
C.3.2 Distance (gap) from the top of the crane vehicle to point the bottom of the bearing structure of the roof sagging (or objects associated with them) are not smaller than 100 mm taken.
C.3.3 For roof structures need to ensure that when including their deflection, slope of the roof is not less than 200
l
in one of these directions (except in the cases mentioned in the objective
Other standard).
C.3.4 Deflection limited by the requirements of psychophysiology of floor units (beam, plate), stairs, balconies, loggia, rooms in houses and public buildings, the workroom workshop need identified by the formula:
158
TCVN 5574: 2012
u(
• 30
•
• qppgf )
first
(C.2)
bp • n twelfth • qp•
•
Inside:
g
is the gravitational acceleration;
p t he standard value of the load due to weight-induced oscillations, taken as in Table C.2;
p t first he standard values have been diminished by the load floor, taken from Table 3,
TCVN
2737: 1995 and Table C.2;
q t he standard value of the load due to the weight of the components are calculated and the Structural lean on them;
n
frequency when the travel load, taken from Table C.2;
b
coefficient, taken from Table C.2.
•
Deflections should be determined by the sum of the load
Inside:
•
Al
•
0,
• 0 4, 6
•
l Al
with At he load area, AA first
• qp
A first = 9 m 2 .
Table C.2 - Score b Room type (according to Table
p
p first
n
b
3, ISO 2737: 1995)
kPa Items 1, 2, except the living room and the classroom; Section 4, 6b,
0.25 14b, 18b
kPa Taken according to Table 3 in
TCVN 2737: 1995
Hz
1.5
125
1.5
125
pal
• Q
Section 2: classrooms and living rooms; Section 7, 8 except ballroom, sidelines; Section 14a, 15, 18a, 20
0.5
As above
pal
• Q
Section 8: ballroom, sidelines; Section 9 1.5
0.2
2.0 50
NOTE:
Q is the weight of a person obtained a 0.8 kN. •
is taken by 1.0 coefficient for structural beams generated in the diagram, obtained a 0.6 for the remaining components (such as millet slab under three or four edges).
a s tep beam, the width of the floor, m.
l t he pace of structural calculations.
C.4 The limited lateral deflection of structural columns and braking loads by crane
C.4.1 Lateral deflection of the column with crane, viaducts, as well as crane beams and brake structure (beams and trusses) taken from Table C.3 but not less than 6 mm. 159
TCVN 5574: 2012
Deflection should be checked at the height of the rails on the crane according to the braking force of a crane work towards cross the path of the crane, regardless of the tilt of the nail. C.4.2 Degree translate into limited lateral of road crane, viaduct outdoors due to the load horizontally and vertically by a crane cause (regardless of the tilt of the nail) with the requirements of technology taking by 20 mm.
f c olumn of the cranes, viaducts,
Table C.3 - The limited lateral deflection u
crane beams and structural brake
Group work mode
Deflection limits u
f of the
of crane Crane beams and structural restraints,
Column
Houses and viaduct
out side
house and bridge (both
Viaduct in
indoor and outdoor)
home
1K-3K
00 hour / 5
500 hour / 1
hour / 500
4K-6K
000 hour / 1
000 hour / 2
000 hour / 1
7K-8K
000 hour / 2
500 hour / 2
000 hour / 2
NOTE:
hour is the height from the top of the nail to the tip of the rail crane (for the 1 story and bridges leading outdoor or indoor) or the distance from the axle beam to the top of the rail crane (for the upper floors of the multi-storey);
Lr hythm calculation of structures (beams).
C.5 horizontal displacements and deflection of the frames, the individual components and bearings due to wind loading conveyor, the inclination of the nail and the impact of temperature and climate
C.5.1 Limited horizontal displacement of the frame is taken at the request structure (to ensure integrity of the frame as the insertion layer walls, walls, doors and the details pane) are shown in Table C.4, the instructions about determining displacement for in C.7.9.
C.5.2 Horizontal displacement of the frame to determine the need to mention the inclination (rotation) of the nail. In which the load due to the weight of the equipment, furniture, people, materials containing only mention when loads are substances are on the whole all the floors of multi-storey building (with reduced dependency on the floor), except for the cases foreseen under the plan other load conditions of normal use. The inclination of the nail should determine whether to wind load, taking 30% of the standard values.
C.5.3 The horizontal displacement of the frame not by wind loads without limitation if walls and partition walls and the details link was calculated durability and resistance to cracking. C.5.4 Deflection of lateral limits to the requirements of the post and beam structure gables, as well as the walls of the panel due to wind loads to be taken by 200 of columns or panels.
160
l
, Inside l l ength calculation
TCVN 5574: 2012
f request structure
Table C.4 - Transfer your lateral limits u
Link between walls, walls compartment in the frame
, Walls and walls
Displacement limit
f u Any
1.Nha multiple floors.
2. One of the multi-storey floors
500 hour
Soft
a) wall, brick walls, plaster concrete, reinforced concrete panels
Hard
b) Natural stone wall tiles, made from blocks of ceramic or made from glass
Hard
00 hour / 3 S
hour / 5 00 S
hour / 7 00 S
wall
3. The one-story (with load bearing wall itself) height floor S
hour HPN
50 hour / 1 S
small or equal
hour , m
to 6 hour
hour / 2 00 S
Soft
bang15 hour greater
00 hour / 3 S
than or
30 Symbol:
hour m ulti-storey building height is taken the distance from the
surface of the shaft foundation to roof the floor supporting beams.
hour is the height of a storey floor in degree on the distance from the foundation to the underside of the rafters; In multi-storey house: on the ground floor - the S distance from the surface of the shaft foundation to roof the floor supporting beams: For the remaining floor by the distance between the axis of the beam each floor. NOTE 1: For intermediate values S
hour ( u nder section 3) horizontal displacement should limit determined by linear interpolation. NOTE 2: For the top floor of the multi-storey building, designed using structural roof deck one floor, the horizontal displacement limit as for the need to get a story. In
hour t aken from the axis of the beam
which the top floor height S floor to the underside of the structural trusses.
NOTE 3: The link includes links soft wall or walls with a frame, does not prevent movement of the frame (not transmitted to the wall and the wall internal forces can damage the structural detail); Hard links include links hinder the mutual movement of the wall or wall bracket.
NOTE 4: For a floor with the walls (as well as the missing piece of the hard floor and roof) and floors of multi-storey building, the horizontal displacement limit allowed
hour / 1 50).
increased 30% (but not greater than S
C.5.5 Deflection of lateral limits to the requirements of technology of conveyor bearings due to wind load, taken by 250 hour
, Inside hour i s a height from the foundation to the underside of the gantry
or beams. C.5.6 Deflection lateral limits of the frame column due to the effect of temperature, climate and settlement obtained by:
hour / 1 50 - when the walls and walls of brick, plaster concrete, reinforced concrete or panels assembled.
161
TCVN 5574: 2012
hour / 2 00 - when the wall is clad in natural stone, made of ceramic or made from block glass wall, which hour i s the height of floors, to house a floor crane, hour i s a height from the foundation to the underside of the crane beams.
Meanwhile the effects of temperature to be taken irrespective of the change in air temperature and diurnal temperature difference caused by solar radiation.
When determining the lateral deflection due to the effects of temperature, climate and subsidence, their value should not sag due plus wind load and the inclination of the nail.
C.6 The rainbow of structures of the floor structure between floors due to compressive forces advance
C.6.1 Camber limit u
f f loor of structures between floors according to the requirements in terms of composition, is
taken by 15 mm when l • 3 m and 40 mm when l • 12 m (for values l i ntermediate camber limit determined by linear interpolation).
C.6.2 camber f need identified by previous compression force, the weight of the structures themselves and the weight floor flooring layers.
C.7 Method of determining deflection and trans (reference) C.7.1 When determining deflections and displacements should mention all the fundamental factors affecting the value of them (deformed inelastic material, the formation of cracks, regardless of deformed scheme, the adjacent texture, tenderness of buttons and background). When there is enough basis, can not take into account a number of factors into account certain or by approximate methods.
C.7.2 For structural materials using magnetic variables need to mention the increased sag over time. When limiting deflection request psychophysiology only come from short-term movements appear immediately after loading also on demand technology and structure (unless calculations include wind loads), Beauty and the mind creep of the count full.
C.7.3 When determining the deflection of the single-storey columns and horizontal load viaduct by the crane to pick diagrams of column mentioned conditions associated with the assumptions:
•
Column indoor and indoor bridge with no horizontal movement in elevation pillow top (if not the floor roof forming hard pieces in
the horizontal plane, it is necessary to mention the softness of the pillow horizontally this);
•
Column in the outdoor bridge is regarded as cantilever.
C.7.4 When in-house and works with technology equipment and transport, causing oscillations to building structures as well as the source of vibration, the limit value of displacement vibration, velocity, vibration and acceleration vibration needed must be taken according to the requirements of vibration in the workplace and accommodation in the relevant standards. When the equipment and tools with high accuracy, sensitivity to vibrations of structures that we put on it, the limit value of displacement vibration, velocity, vibration and acceleration vibration need to identify with separate technical conditions.
C.7.5 Scenario calculations * w hich should determine deflections, displacements and the corresponding loads, have to choose depending on the calculation is done according to the requirements.
162
TCVN 5574: 2012
If the calculation is done according to the requirements of the technology, the situation needs to correspond to calculate the impact of the load, which affects the work of the technological equipment. If the calculation is done according to the requirements in terms of composition, the situation needs to correspond to calculate the impact of the load causing structural damage to adjacent displacement due to camber and too big. If the calculation is done according to the requirements of psychophysiology, situations calculated to correspond to state-related oscillations of the structure. When designers need to mention the loads that affect the oscillation (of the structure) satisfies the requirements of C.7.4 and of this standard. If the calculation is done according to the requirements of aesthetic and psychological situations calculated to correspond to the impact of frequent load and long term.
For the roof structure and the floor is designed with camber initially, when limiting deflection according to the requirements of the psychological and aesthetic, sag vertical is determined to reduce a quantity equal to the value that initial camber. NOTE: * Scenario calculations: S et of conditions to determine requirements for the structural calculations, were included in the calculation.
Scenario calculations characterized by schematic calculations of the structure, type of load, the value of the coefficient of working conditions and the factors of reliability, the limit state considered in situations calculated that math.
C.7.6 Deflection of structures floors and roof are limited to the requirements in terms of composition, does not exceed the distance (gap) between the underside of the structures and the upper surface of partition walls glass walls, casement, lower door bearing structures.
A gap between the underside underside of the roof deck constructions, floor floor between floors and walls below below the upper surface of the structures that do not exceed 40 mm. In the case when implementing the requirements on which to increase t he hardness of the floor and roof deck, the need to avoid an increase in hardness that these measures formed (eg do not put the walls under the girder bending that puts beside).
C.7.7 In cases where there are walls between the bearing wall (in fact the same height with the wall) value l S ection 2a in Table C.1 should take the distance between the bearing surface of the wall (or column) and the wall (or between the inner surface of the wall as shown in Figure C.1). C.7.8 Deflection of the structural trusses when the crane hanging rails, (Table C.1, paragraph 2d) to be taken by the difference between the deflectionfirst
f and
2
f o f the adjacent structural trusses (Figure C.2).
C.7.9 Lateral displacement of the frame to determine the plane of the wall and the wall, but their integrity should be ensured.
When in the frames of the multi-storey link with height of 40 m in the array tilt floor adjacent to the hard wall, taken by S1
500l Section 2; 500l
to Section 2a; 700
l
•/
2
/ lfhf(Figure C.3), does not exceed (Table C.4):
300
l
for
to 2b.
163
TCVN 5574: 2012
a)
5
6 3 4 first
2
first l first
b)
l 2 2
3
5
4
6 first l first
first
first
2
6
l 2 2
2
l 3 3
a) there is a wall; b) has two walls; IMPORTANT INSTRUCTIONS:
1 - bearing walls (or column); 2 - Wall compartment;
3 - floor between the floor (or roof deck) before the load; 4 - Exchange between the floor (or roof deck) when loads; 5 - Line markers to calculate the deflection; 6 gap.
Figure C1 - Diagram determine values l ( f irst
l, 2 l, 3 l),w hen the wall
between the bearing compartment wall
164
first
TCVN 5574: 2012
4 f 2 2 first
2
f 2 2
first f first
first first
a
first
first
a
3
a
a
IMPORTANT INSTRUCTIONS: INSTRUCTIONS: 1 -
Structural trusses;
2 - supporting beams hanging crane rails; 3 - crane
hanging;
4 - Position the original structural trusses; f first - deflection of the load bearing structural truss most; f 2 - deflection of structural truss rafters near load bearing structure most.
Figure C2 - map to calculate the deflection of structural trusses when
crane rails of hanging
first
2
first f first
2 f
S r u o h
l
Figure C3 - Diagram of the array deviation 2 under the floor, adjacent to the indoor hard wall bracing frame 1 (the solid line only original diagram of the frame before the load)
165
TCVN 5574: 2012
Appendix D
(Regulations)
The group's working mode and hoisting crane hanging crane
institutional group
Conditions of Use
Working - Manual operation (all kinds)
1K - 3K - Any
- With hanging pulley transmission
- For repairs, conveyed with intensity limited
which clamp - Crane with winch car transporters
- Used in the powerhouse of hydropower stations, for the assembly and
which clamp
delivery with limited intensity
- Crane with winch car transporters
4K - 6K - Used in conveying with medium intensity;
which clamp
for work on the technology in mechanical workshops, warehouses for finished products of enterprises of building materials; for the storage of metal products consumption
- Crane grabs with two cable types,
- Warehouse mixture, used to work with different kinds of load
type grab crane with magnetic
- Cranes magnetism
- Cranes for forging and I, casting
- In stock semi-finished products, work with different kinds of load
7K
- Crane grabs with two cable types,
- In the workshop of metallurgical plant
- Material storage pile, scrap uniform (working one or two shifts)
type grab crane with magnetic
- Crane technology to work around the clock
- Crane with load carrying vehicle winch types including clamp. - Horizontal crane, grabs trough,
8K
- In the workshop of metallurgical plant
feeding trough, crane used to unload the steel ingot casting, use crushed crane, crane furnace
- Magnetic crane
- In workshops and warehouses of metallurgical plants, large metal warehouse with consistent product
- Crane grabs with two cable types, type grab crane with magnetic
166
- Warehouse piled materials and scrap uniform (working day and night)
TCVN 5574: 2012
Appendix E
(Regulations)
Variables used to calculate according to reliability
Table E.1 - The quantity
•
•
•
•
0.01
0.995
.010
0.26
.870
.226
0.51
.745
.380
0.02
.990
.020
0.27
.865
.234
0.52
.740
.385
0.03
.985
.030
0.28
.860
0.241
0.53
.735
.390
0.04
0.980
0.039
0.29
.855
.248
0.54
.730
.394
0.05
.975
0.049
0.30
.850
0255
0.55
.725
.399
0.06
.970
.058
0.31
.845
.262
0.56
.720
.403
0.07
0.965
.068
0.32
.840
.269
0.57
.715
.407
0.08
.960
0.077
0.33
.835
.276
0.58
.710
.412
0.09
.955
.086
0.34
.830
.282
0.59
.705
.416
0.10
.950
0.095
0.35
.825
.289
0.60
.700
.420
0.11
.945
0.104
0.36
.820
.295
0.62
.690
.428
0.12
.940
0.113
0.37
.815
0.302
0.64
.680
.435
0.13
.935
.122
0.38
.810
0.308
0.66
.670
0.442
0.14
.930
.130
0.39
.805
.314
0.68
.660
0.449
0.15
.925
.139
0.40
0.800
.320
0.70
.650
.455
0.16
0.920
.147
0.41
.795
.326
0.72
.640
.461
0.17
.915
0.156
0.42
.790
.332
0.74
.630
.466
0.18
.910
0,164
0.43
.785
.338
0.76
.620
.471
0.19
.905
.172
0.44
.780
.343
0.78
.610
.476
0.20
.900
.180
0.45
0.775
.349
0.80
.600
.480
0.21
.895
.188
0.46
.770
.354
0.85
.575
.489
0.22
.890
.196
0.47
.765
.360
0.90
.550
0.495
0.23
0.885
.204
0.48
.760
.365
0.95
.525
.499
0.24
.880
.211
0.49
.755
.370
1.00
.500
.500
0.25
0.875
0.219
0.50
.750
0.375
-
-
-
• m
•
•• •• m
• m
•
•
• m
167
1 7 0
Table E.2 - Values •• R
• , •
R
for structures made of heavy concrete
Coefficient of
C Hamlet compressive strength of concrete
Group Reinforced
working conditions of
Symbol
tensile
B12,5
B15
B20
B25
B30
B35
B40
B 45
B50
B55
B60
concrete • b 2
0.9
Any CIII, A-III ( • 10-40) and Bp-I ( • •44; ; 5) 5) CII, A-II
CI, AI
1.0
Any CIII, A-III ( • 10-40) and Bp-I ( • •44,5) ,5) CII, A-II
CI, AI
1.1
Any CIII, A-III ( • 10-40) and Bp-I ( • •44,5) ,5) CII, A-II
CI, AI
• •
•0 85,
0,
NOTE: Value
•• R
R
b
• R •
•
•
.796
.789
.767
.746
.728
.710
.692
.670
.652
.634
.612
• R
.662
.654
.628
.604
.583
.564
.544
.521
.503
.484
.463
•
.443
0.440
.431
.421
.413
0.405
.396
.385
.376
.367
.356
• R
.689
.681
.656
.632
.612
.592
.573
.550
.531
.512
.491
•
.452
0.449
0.441
.432
0.425
.417
.409
.399
.390
.381
.370
.700
.675
.651
.631
.612
.593
.570
.551
.532
.511
R
R
• R
.708
• R •
.457
.455
.447
.439
.432
0.425
.417
.407
.399
.391
.380
.790
.782
.758
.734
.714
.694
.674
.650
.630
.610
.586
• R
.628
.619
.590
0.563
.541
.519
.498
.473
.453
0.434
.411
•
.431
.427
.416
0.405
.395
.384
.374
0.361
.351
.340
.326
• R
.660
.650
.623
.595
.573
.552
.530
.505
0.485
.465
0.442
•
0.442
.439
0.429
0.418
.409
.399
.390
.378
.367
0.357
.344
• R
.682
.673
0.645
.618
.596
.575
.553
.528
.508
.488
0.464
• R •
0.449
.446
.437
.427
.419
.410
.400
.389
.379
.369
.356
.784
0.775
.749
.722
.700
.808
.810
.630
.608
.586
.560
• R
.621
0.611
.580
.550
.526
.650
.652
.453
.432
.411
.386
•
.428
0.424
.412
.399
.388
.439
0.440
.351
.339
.326
.312
• R
.653
.642
.612
.582
.558
.681
.683
0.485
.463
0.442
.416
•
0.440
.436
0.425
.413
.402
0.449
.450
.367
.356
.344
.330
R
R
R
R
• R
.675
.665
.635
.605
.582
.703
.705
.508
.486
0.464
0.438
•
.447
.444
.433
.422
.412
.456
.456
.379
.368
.356
.342
R
• ;
R • •1 1; 008 • u s • ,sc •
•
and R
•
• • • 1first•
•
• • RR • • 0 1, 5 • R •.
given in the table regardless of the coefficients
bi
•
given in Table 14.
1 6 8
TCVN 5574: 2012
Appendix F
( Regulations)
Simple beam deflection Beam deflection simple work or millet diagram free cantilever is determined by the formula:
2
• •first • mm• LRF
(F.1)
Inside:
•firstr •m determined according to the formula (158) when there are no cracks in the tensile and (173) when there are cracks in the tensile zone;
• the characteristic load factor, taken from Table F.1;
T C V N 5 5 7 4 : 2 0 1 2
TCVN 5574: 2012
Appendix F
( Regulations)
Simple beam deflection Beam deflection simple work or millet diagram free cantilever is determined by the formula:
2
• •first • mm• LRF
(F.1)
Inside:
•firstr •m determined according to the formula (158) when there are no cracks in the tensile and (173) when there are cracks in the tensile zone;
• the characteristic load factor, taken from Table F.1; Table F.1 - Score •
Load diagram
Load diagram
•
q
•
q
41
48 5
l
l
F
F
1 first thirty
12
l
l/2
F
l/2
F
F 2
• • • • • • 3 6 lala •
a
la
• •
•
• 2 1• 1 •
• firstand M,first • 2
6
2
la
la
NOTE: The case of beam subjected to multiple load types according to the diagram in Table F.1,
Inside:
8•1
and
M,2 ...,
important. In this case, in the formula (F.1)
•
1
2
2
• is determined by the formula:
• .. . • • MMM nn
(F.2)
• .. . • MMM n
• n and M r espectively coefficients • a nd the largest bending moment diagram for each load n firstr •m is determined for a value of bending moment M is the sum of values
maximum bending moment diagram for each load).
169
