RC Detailing to BS 8110 S A Karunaratne 29-01-2013
(I)
Paper & Envelope Sizes & Drawing Sizes
(II)
Title Panel, Scales, Line Thickness & Abbreviations
(III)
Layouts, Axes & Grid Lines & G A Drawings
(IV)
Levels & Dimensions
(V)
Slabs & Beams
(VI)
Columns & Walls
(VII)
Staircases
(IIX)
Corbels & Nibs
(IX)
Footings, Piles & Pile Caps
(X)
Bar Bending Schedules
What is presented ?
(XI) What should be done & what should not be done
Paper & Envelope sizes ISO 216 sizes
ISO 216 sizes
ISO 269 sizes
(mm x mm)
(mm x mm)
(mm x mm)
Paper - A Series
Paper - B Series
Envelopes - C Series
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10
841 594 420 297 210 148 105 74 52 37 26
x x x x x x x x x x x
1189 841 594 420 297 210 148 105 74 52 37
A0 aspect ratio is 1 : √2 & area is 1m2
B0 1000 x B1 707 x B2 500 x B3 353 x B4 250 x B5 176 x B6 125 x B7 88 x B8 62 x B9 44 x B10 31 x
1414 1000 707 500 353 250 176 125 88 62 44
B0 is 1m to √2m & GM between A series same number and one lower
C0 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10
917 648 458 324 229 162 114 81 57 40 28
x x x x x x x x x x x
1297 917 648 458 324 229 162 114 81 57 40
GM between B series same number & A series same number
Sizes of Paper A & B & Envelopes C are defined by halving preceding size
3 A1
A0
5
6
4
A2
Size A Paper fits to same size Envelope – e.g., A4 to C4 Size B Paper fits to one number lower size Envelope – e.g., B4 to C3
Notes
MA2-4 MA0-1
M A0-1 = 20 Minimum M A2-4 = 10 Minimum Design stage changes
Margin Thickness = 0.5mm minimum
Revisions
Title Panel
M L = 20mm minimum
105
Drawing Margins & Title Panel
75 - 200
MA2-4 MA0-1
Title Panel should include: Main & Associated Consultants (If Applicable) Project Title Client’s Name (If Applicable)
Drawing Title Drawn by (Name) Designed by (Name) Checked by (Name & Signature) Approved by (Name & Signature) Scales & drawn Scale Office Job Number
Drawing Number & Space for Revision Suffix Date of Drawing Office of origin of Drawing Copy Right Protection Statement
Recommended sizes of drawings General Arrangement Drawings (G A) Reinforcement Drawings Details
: A1 : A1 : A3 & A4
Recommended scales GA
1 : 100
Beam & Column elevations 1 : 50
Wall & Slab details
1 : 50
Beam & Column sections
1 : 20
Recommended thickness of lines Dimensions & center lines Concrete outlines & G A drawings
0.25mm 0.35mm
Concrete outlines & R/F drawings Links, hoops & cross-ties
0.35mm 0.35 – 0.7mm
Main R/F bars
0.7mm
Changes & Revisions should include: Suffix; numeral for changes – 1, 2, 3, ----- & letters for revisions – A, B, C, -Brief description of revision
450
Revision made by (Name & Signature) Date of revision Cloud revised details
A
Beam depth changed 300 to 450
Revision Description
250
SAK Made by
24-06-2008 Signature
Date
Notes should include: Cross references to GA Drgs Cross references to connected Detail Drgs List of abbreviations Grade of concrete
(i) Main bar size minus link size (40 -10) = 30mm
(ii) Exposure – moderate - C40 – 30mm Cover to R/F (iii) 1 ½ hour fire resistance – 20mm
(iv) 20 mm aggregate size – 20mm
30mm
BS 8110 – Exposure conditions Specify nominal cover to all reinforcement including links o Mild – Protected from weather or aggressive conditions o Moderate – Sheltered from severe rain, subject condensation, continuously under water, in contact with non-aggressive soil o Severe – Exposed to severe rain, alternate wetting and drying or severe condensation o Very severe – Exposed to sea water spray, corrosive fumes o Extreme – Exposed to abrasive action or machinery or vehicles
BS 8110 – Table 3.4 Nominal cover to meet durability requirements Condition of exposure
Nominal cover
Mild Moderate Severe Very severe Extreme Max. w/c ratio
mm
mm
mm
mm
mm
0.65
0.60
0.55
0.50
0.45
Min. cement (kg/m3)
275
300
325
350
400
Lowest concrete grade
C30
C35
C40
C45
C50
25 -
20 35 -
20 30 40 50 -
20 25 30 40 60
20 20 25 30 50
Cover may be reduced to 15mm aggregate not exceeding 15mm Table is for normal-weight aggregate of 20mm nominal max. size
BS 8110 – Table 3.5 Nominal cover to meet fire requirements Fire resistance
Nominal cover Beams Floors Ribs Columns SS Cts SS Cts SS Cts
h
mm
mm
mm
mm
mm
mm
mm
0.5
20
20
20
20
20
20
20
1
20
20
20
20
20
20
20
1.5
20
20
25
20
35
20
20
2
40
30
35
25
45
35
25
3
60
40
45
35
55
45
25
4
70
50
55
45
65
55
25
Cover may be reduced to 15mm aggregate not exceeding 15mm Additional measures are required to reduce spalling Cover to main R/F given in Tables 4.2 & 4.3 is considered.
BS 8110: Part 1: Section 7.3
COVER TO REINFORCEMENT Reference to EuroCodes BS EN 206-1 Concrete – Part 1: Specification, Performance, production & conformity
BS 8500-1 Concrete – Part 1: 2002 Method of specifying & guidance for the specifier BS 8500-2 Concrete – Part 2: 2002 Specification for constituent materials & concrete ; BS 5328 withdrawn 1-12-2003
A List of Abbreviations ABR
= Alternate Bar Reversed
Blk
= block work
Bw
= Both ways
B
= Bottom
Bwk
= Brick work
Crs
= Centres
¢
= Centre Line
dia or F = Diameter
drg
= drawing
EF
= Each face
EGWL = Existing ground water level
EL
= Existing level
FF
= Front face
FFL
= Finished floor level
FS
= Full size
H
= High tensile steel
horiz
= Horizontal
R
= Mild steel / Round bars
NF
= Near face
NTS
= Not to scale
pkt
= pocket
RC
= Reinforced concrete
RRM
= Random rubble masonry
SFL
= Structural floor level
T
= Top
vert
= vertical
Recommended practices in drawing preparation Site Plan drgs
: should show North Point
All other drgs
: to site plan orientation
Continuation drgs
: provide key plan / portion covered
N
provide reference continuation drg numbers
R/F drgs
: show large openings; upto 150 x 150 mm &
150F holes need not be shown; but refer to drgs As-Built or Record drgs: amend original drawings as constructed
1
N
7000
6000
E A 6000
6000
Road
6000
Access
D
C
B 6000
6000
1
7000
C
B 6000
2
A
Plan - Detail Main Road
LAYOUT PLAN
E
D
DETAIL PLAN
ORIENTATION OF DRAWINGS
6000
1
1
2
3
B
A
Key Plan
A
Floor slab A1 - 22nd Level
Detailed Area is marked in Key Plan
Grid lines & Axes LUC
A
LLC
Beam reference is panel LLC column identification & a suffix say A11, A12 etc
A21
Columns A1, A2 are at intersection of A & 1, A & 2 etc
A12
3 C
C22 B23
B22
B31
B12
B
A11
Grids commence at LUC and right
C12
2 C
A23
A31
C C
B21
1 C
B11
Axes commence at LLC and up. Omit I and O
A22
Structural General Arrangement Drawing (BASED ON ORIGINAL DRAWING BY OTHERS)
GENERAL ARRANGEMENT DRAWING
C25/ 30
Concrete C40/50
C35/45
C32/40
C25/30
C20/25
Concrete Grades in High Rise Buildings
Building Structures are Designed from top (roof) to bottom (foundations) Building Structures are usually constructed from foundations to roof Therefore typical details should be referred from bottom (foundation level) to top (roof level) and not from top to bottom to avoid confusion at construction stage.
Levels
in metres
(a) For major works use Ordnance Survey (OS) datum (b) Civil & major Building works use a TBM or transferred OS datum (c) For minor works use a job datum wrt a suitable fixed point On plan levels are indicated within a rectangle and preferably described SSL 155.075 On Elevations & Sections project beyond drawing with closed FFL SSL arrowhead 155.075
50
Dimensioning recommendations Unit for layouts and levels is metre; say 2.450, 128.400, 9.125m Unit for R/F and sections is millimeter; say 5, 35, 2575 (can avoid writing mm and dimension to whole mm) Place dimensions above and not through dimension lines or not inside details. Place to view from bottom or RHS of drg.
G A drgs should give setting out dimension & sizes of members
Dimensions in R/F drgs only to show correct location of R/F.
GENERAL ARRANGEMENT DRAWING SHOWING DIMENSIONING AND LEVELS
SLABS 1 BAR CURTAILMENT SIMPLE RULES
SLABS 2 BAR ANCHORAGE
TYPICAL ONE-WAY SPANNING SLAB
TYPICAL
TWO-WAY SLAB
SLAB R/F ARRANGEMENT
1
2
3
4
5
6
7
8
H G F E
Open courtyard D C B A
From experience recommend continuous nominal top R/F in: (1) All coloured panels preferably in open courtyard situations (2) All the slab panels in a roof to avoid shrinkage cracks
TYPICAL FLAT-SLAB PANEL 1
Flat Slab Raft Foundation & Column R/F Starter Bars
TYPICAL FLAT-SLAB PANEL 2
Flat Slab Raft Foundation with a Deep Beam at Change of Levels
Trimming of holes in normal slabs 1 Conditions
l = length w = width (a) wras - max = 1000 ps = parallel to span (b) wmin - used = w1 = 250 (assume) lps lps used = unsupported lps edge distance (c) lps - max = 0.25 l x = 1000 wa-i wras w1 = = ras = right angle to span (d) wtotal - max = 0.25 l y = 1500 wmin - used (e) Small holes with sides (F ) <= 150 could be neglected structurally
l x = 4000
l y = 6000
(f) For holes side < = 500 displace bars either side; space checked
Cut & replace equal area bars either side. Extend bars 45F beyond hole
45F
TRIMMING OF HOLES 2 (g) If hole side (500 - 1000) treat as in (f) but trim with similar bars at top.
45f min
If element depth is >= 250 furnish diagonal bars top and bottom.
(h) In group of holes within 500 or less treat as single hole and trim as in (f); but bars should pass alongside where possible. (i) In group of holes within 500 and 1000 treat as single hole and trim as in (f) and (g).
® Cutting element bars passing through hole and furnishing a stirrup as a trimmer is totally wrong
Joints in Slabs 1 Control joints a retooled, sawed, or pre-moulded joints to allow for shrinkage of large concrete areas.
Control joints create a weakened section that induce cracking to occur along the joint, rather than in a random fashion. Isolation joints provide a separation between a slab on grade and columns or walls, so that each can move independently.
Expansion Joints 2
In a 100mm thick concrete walkway, what is the typical spacing for expansion joints? 6m on center accommodates movement due to both expansion and contraction
EXPANSION JOINTS 3
BEAMS 1 BAR CURTAILMENTS SIMPLE RULES 1
BEAMS 2
BEAMS 3 ANCHORAGE & LAP LENGTHS
Beam R/F Detailing Methods (i) If pre-assembled main R/F, hanger bars & links stopped 50mm short of face of support & splice bars used at supports.
(ii) If assembled at works - Span main bars lapped at or near the support. Link support bars lapped with ends of top main bars. (iii) Max. link space 0.75d longitudinal & 150mm horizontal space between tension bars (iv) Max. area Asc or Ast <= 4%bh; Min. Asc > = 0.2 & Ast >= 0.13 (V) Maxim. Clear Distance between tension bars ab<=160 Short line at 300 and tagged
“Calling up” of bars approx. at mid of bar
DETAIL OF SIMPLY SUPPORTED BEAM
DETAILS OF CONTINOUS BEAMS
Holes in Concrete Beams: Circular preferable (1) Checks required (a) Shear capacity and (b) Moment Capacity (2) Additional stirrups and longitudinal bars and trimmer bars are required (3) If long rectangular hole unavoidable, frame with Vierendeel-type truss (4) Locate holes around ¼ o 1/3 span if possible (5) If many holes are required design the beam “oversize” (6) Sizes of vertical holes limit to b/4 & horizontal holes h/4
1
3
2
2500 2500 2500
6500 6500 6500
7500 7500 7500
hagg + 5; but < F or F e
50
50
11R6-08-150 VARIES 25
11R6-08-150 VARIES
23R10-05-250
27R10-05-250
25
23R10-05-250
27R10-05-250
2/3xhagg or F or F e if > = hagg +5
Min. distance between bars
Bar curtailment not shown completely Sometimes stirrup arrangement not shown
Correct & unacceptable beam labeling
150
450
750
sb
450
b = 500 >1000 for EC2
b =500
ab <= 160
F side bar =
√
sb x b / fy
sb =<250; F = 16 sb =<150; F = 12 for EC2
Beam side bar detailing Correct & wrong practices
Even in EC2
®
1000
DISCONTINUITY OF VERTICAL LEG
1000
DO NOT ALLOW
115 800
TIE ALL COMPRESSION BARS TIE TENSION BARS WHEN GAP >150
185 800
TENSION BARS COMPRESSION BARS SIDE BARS
CORRECT STIRRUP ARRANGEMENT
SINGLE STIRRUP WRONG
Wide beam stirrup arrangement
A very deep beam shows link arrangement
SIMPLE COLUMN DETAIL (1) Main R/F Max. 6%bh; Min 0.4%bh; Max area at laps 10%bh (2) Min. Bar size 12mm; circular columns 6 number of bars (3) Min. joggle offset = 2F + 10% tolerance (4) Min. joggle length – 10 x centre-lineoffset or 300mm Min.
(5) Allow 75mm for kicker (6) Min. size of link ¼ F of largest vertical bar (7) Max. pitch – 12 F smallest compression bar
(8) All vertical bars to be tied if space > 150mm and all alternate bars to be tied by links (9) Maximum space between main R/F; Compression <=300 Tension <=175
DETAILS OF COLUMNS 1 ACI 318-02 in new Appendix A recommends hooking bars towards the center of the column to develop full flexural strength of the column.
tension lap
tension lap
®
t
t>= 300; 4 corner bars
t>= 300; 4 corner bars
t< 300; 2 corner bars
t< 300; 2 corner bars
Horizontal bar outside
Horizontal bar inside
easy to fix
difficult to fix
WALL REINFORCEMENT
t
For shrinkage effects (a) Min. R/F both vertical & horizontal
Fy 250
460
0.3%
0.25%
0.15%
0.125%
1 face or
½ each face
(b) Vertical R/F; (i) Min. Asc = 0.4% (0.2% each face) (ii) Max. Asc = 4%
(iii) When Asc > 2%; Max. bar space >= 16 x vertical bar size
WALL VERTICAL R/F INSIDE & HORIZONTAL R/F OUTSIDE
DETAILS OF WALLS
R/F of wall showing horizontal bar placement in outer layer
WALL R/F ASSEMBLY
RETAINING WALL DETAILS SHOWS OUTER HORIZONTAL R/F
500T16-02-250 NF
500T16-02-250 NF
500T16-01-250 NF
12T10-04-200 NF
12T10-05-200 FF
500T16-01-250 NF
12T10-05-200 FF
500T12-03-250 FF
500T12-03-250 FF
12T10-04-200 NF
Correct & unacceptable labeling of wall R/F
STAIRCASE R/F DETAILS
DETAILS OF STAIRCASES
Ast- Main TR; Main tensile R/F. Large bend required on plan
Ast- Main TR; Main tensile R/F. Large bend required as in elevation
Two column links close to corbel top
Ast - Main TR welded to plate or cross bar
Two column links close to corbel top
DO NOT BEND THIS WAY Tension lap
Compression anchorage
Tension lap
Ast - Horiz >= 50% of Ast - Main TR
Compression bars. Area >= 1000mm2/metre of width of corbel
Compression anchorage
Ast - Horiz >= 50% of Ast - Main TR
Compression bars. Area >= 1000mm2/metre of width of corbel
When main tensile R/F <= 16mm F
When main tensile R/F <= 20mm F
Corbel R/F (without welds)
Corbel R/F (with welds)
CORBELS
Tension anchorage length Tension anchor if "U" bars used
Closed links or "U" bars be used
Horizontal "U" bars. F <= 16
Tie to at least two main longitudinal reinforcement Lacer bar same F as horizontal "U" bars
Link F should not more than 12
Standard Nib detail
Shallow Nib detail
NIBS
t >= 140
PAD FOOTING 1
Pad Foundations with Schedule
DETAILS OF FOUNDATIONS 2 – PAD FOOTING & SCHEDULE
Detailing of Pile Locations & Pile Cap Drawings (1) Show the pile centers wrt grid lines (2) Do not indicate dimensions from grid lines to site boundaries (3) Indicate cut off levels and anticipated rock levels (4) Indicate concrete grade, cover to reinforcement (5) Pile diameters, Identity of Pile, Pile Groups and number of piles (6) Pile cap dimensions (7) Indicate column or wall starters (8) Show the radius of bend of main reinforcement of piles (9) Provide outer (peripheral) bursting reinforcement T16@200 (10) Indicate pitch of links if different at top and the rest of the pile length (11) Indicate whether the links are helical or circular (12) Use nominal top reinforcement in large pile caps to avoid shrinkage cracks
i.e. 0.13bh, where h= 250
DETAILING PILES & PILE CAPS 1 T10 - 300
GFL
+0.70 VARIES 500
T10 - 300
+0.20
1200 F PILE
2500
1
75
12T25 1000 F PILE
3800
2
3
7500
7500
1516
8910kN P16
823
P13
P11 1350 1350 P12 PG9 3/900 F
4200kN
1200 1200
6000
1/1200 F
8623kN 823 1516
6000
4572kN
E
6000
4
PILE GROUP SCHEDULE
P10
C
PILE
PILE CAP OUTLINE DETAILS
F
D
PILE CUT OFF LEVEL VARIES
P23
P14 1350 1350 P15 PG9 3/900 F
PILE PILE PILE GROUP F NO NO (mm) S P1 800 S P2 800 P11 900 PG9 P12 900 P13 900 P14 900 PG9 P15 900 P16 900
PILE CUT OFF LEVE (m) -1.250 -1.250 -1.975 -1.975 -1.975 -1.975 -1.975 -1.975
TOTAL NUMBER OF PILES
P22
PILE F NO OF PILES
PG1 2/800 F
1200 1000 900 24 31 15
TOTAL 106
LAYOUT
800 28
600 08
PILES
DETAILING PILES & PILE CAPS 2
DETAILING PILES & PILE CAPS 3 Tie beams detailed at the top of pile cap to reduce construction difficulties. Refer “Pile Design & construction practice” by M J Tomlinson Section 7.8
DETAILING PILES & PILE CAPS 4
(DETAILING PILES & PILE CAPS 5)
Bar bending scheduling to BS 8666, BSI 2000
SHEET 1 – BAR SHAPES
7T16- 05 (a to g) -100 – B1 SEVEN NUMBERS HIGH TENSILE SIXTEEN MM DIAMETER BAR MARK ZERO FIVE VARYING LENGTH a TO h
AT HUNDRED MM CENTERS AT BOTTOM OUTER LAYER
SHEET 2 – BAR SHAPES
SHEET 3 – BAR SHAPES
SHEET 6 – MIN SCHEDULING RADIUS AND BEND ALLOWANCES
Bar schedule ref: 750 0 4
Beam T 01 B1 20 T 02 20 T 03 12 T 04 10 T 05 10 R 06 6 T 10
24-06-08 SAK
Total No Length of each Shape code A mm
No of bars in each
Type & F No of members
Bar mark
Dat 24-05-08 Revised Prepared by : A B C Checked
Member
Typical Bar Bending Schedule
Site ref: 4321
A
B mm
STEMS
2
4
8
5000
00
Straight
2
8
16 1300
12
290
2
3
12 3250
12
130
2
20
80 2280
51
680 380
2
20
40
21
130 380
2
10
20 1955
47
685 385
900
2000
This schedule complies with BS 8666: 2000
680 380 A
What should and should not be done by Junior Structural Design Engineers (1) (2) (3) (4) (5)
Study the scope of works, and understand the Architectural drawings Discuss with senior engineers the concept and develop the GA Drawings Obtain approval from architects the GA drawings Discuss with Building Services Engineers ducts & opening sizes ect. Discuss with Architect, Services Engineers the clear depth between beam soffit & ceilings (6) Use computer meaningfully and double check the outputs with simple manual calculations (7) Obtain approval of sketches from senior engineers prior to draughting (8) Check drawings prior to obtaining senior engineers signature in drawings What should and should not be done by draughtspersons (1) (2) (3) (4) (5)
Study and understand the Architectural drawings Check whether the sketches are signed by senior engineers Study the sketches and if doubtful check with the designer Do not blindly copy (cut and paste) from other details without understanding If schedules are not given elevate all beams in one direction in some order without mixing up in other direction beams (6) Give cross reference to typical details of lower levels not from top levels (7) Indicate overall dimensions in plans & sectional elevation of buildings
Thank you
