Tables for use with Coefficient Method for Two-way Slab design. Previously known as Method 3 of the 1963 ACI Code.
Moment Coefficient for two way slab design ACI 318-63 Method 2
Design of two way slabsFull description
aFull description
This is an example on "How to design a RCC Slab using IS 456-2000".A step by step procedure of slab designing This manual is created based on the value obtained from "SLAB DESIGNER ver 2.00" whi...
A basic design steps following IS 800 : 2000 of One way slab.Full description
combined footing
A basic design steps following IS 800 : 2000 of One way slab.
Guide for structural design of one way slabs and girders
The Coefficient Method is a method of designing two-way slabs that are supported by edge beams. Previously known as Method 3 of the 1963 ACI Code.Full description
The Coefficient Method is a method of designing two-way slabs that are supported by edge beams. Previously known as Method 3 of the 1963 ACI Code.
Date : 8/Sep/03 CONTROL ROOM AT VAPI FIRST SLAB LEVEL Design of Two way slab marked : General Data Grade of Concrete Grade of Steel Density of Concrete Shorter Span of slab Lx Longer Span of Slab Ly Ly/Lx Edge condition (Panel)
:
S3 = = = = =
M20 Fe415 25 3 5
( 20 ( 415 kN/m3 m m
N/mm2 ) N/mm2 )
= 1.666667 . 5 Two Short Edges Discontinuous
Trying and adopting Thickness of slanb Clear Cover to reinforcement Loading on Slab Dead Load - Self Weight ( 0.14 x 25 ) - Floor Finish load - Other Dead Load
= =
140 15
mm mm
= = =
3.5 1
kN/mm2 kN/mm2 kN/mm2
Live Load
=
5
kN/mm2
Total Design Load
=
9.5
kN/mm2
Along Short Span Moment coefficient a
Midspan 0.047667
Mu = 1.5 ( a x w x Lx2)
Along Long Span
Support 0.063333
Midspan 0.035
6.11325
8.1225
4.48875
0
121
121
117
117
K = Mu/bd2
0.418
0.555
0.328
0.000
Pt of steel required
0.124
0.165
0.098
0.006
Area of Steel Required
150
199
115
7
Ast min @
168
168
168
168
Effective Depth
0.12 %
Provide Dia. And Spacing as (# indicates HYSD Bar) Extra top
#8 250 mm c/c
Area of Steel Provided Pt. Provided
Support 0
#8 250 mm c/c #8 500 mm c/c
#8 250 mm c/c
#8 250 mm c/c #8 500 mm c/c
201.06
301.59
201.06
301.59
0.1662
0.2493
0.1718
0.2578
Date : 8/Sep/03 CONTROL ROOM AT VAPI FIRST SLAB LEVEL DEFLECTION CHECK :- (REF. CLAUSE 23.2.1 OF IS:456) Basic Allowable 'Lx/d' ratio without modification Steel Stress of Service Loads is given as fs = 0.58.fy [ Ast / Ast(pr.) ] Modification factor as per SP:24 (Clause 22.2) 1 0.225+0.00322.fs-0.625 log10(bd/Ast(pr))
=
Permissible 'Le/d' ratio with modification factor Actual Span/Depth ratio, Lx / d
= =
= =
26 180.12 N/mm2 1 0.317827
=
26.000 x 24.793 <
2 2.0000 52.000
( subjected to max MF=2
= 52.000 HENCE O.K.
REFERENCES :1)
IS:456 (CODE OF PRACTICE FOR PLAIN AND REINFORCED CONCRETE 2000)
A) TABLE : 26 BENDING MOMENT COEFFICIENT FOR RECTANGULAR PANELS SUPPORT ON FOUR SIDES WITH PROVISION FOR TORSIONAL REINFORCEMENT. B) CLAUSE 26.5.2.1 FOR MINIMUM REINFORCEMENT IN SLABS 2)
SP:16 (DESIGN AIDS FOR REINFORCED CONCRETE TO IS:456 - 1978) CHART:22 CONTROL OF DEFLECTION (PAGE NO. 44)
3)
EFFECTIVE DEPTH CALCULATION :ASSUMED OVERALL DEPTH CLEAR COVER TO REINF. MAXIMUM BAR SIZE
= = =
140.00 mm 25.00 mm 10.00 mm
EFF. DEPTH FOR MAIN REINF.
= = = =
140.00 110.00 110.00 100.00
EFF. DEPTH FOR SEC. REINF.
mm mm
25.00 10.00
MATERIALS USED :1) 2)
GRADE OF CONCRETE GRADE OF TOR STEEL
1)
DESIGN OF SLAB MARKED :
= =
M20 Fe415
TS1, TS22
THICKNESS =
DATA AVAILABLE :SPAN ALONG SHORTER SIDE, Lx SPAN ALONG LONGER SIDE, Ly RATIO OF SPANS, Ly / Lx CONTINUITY ALONG PERIPHERY
= = = =
5.230 m c/c. & = 5.760 m c/c. & = 1.1060 TWO ADJACENT EDGES DISCONTINUOUS
= =
0.140 x (assumed)
DEAD LOADS :a) Self weight of slab b) Floor-finish + Water-proofing
2550 = =
c) False Ceiling
=
50.00
=
LIVE LOADS :a) Considering accessible roof THUS TOTAL LOADS, w
= =
DESIGN PARTICULARS
ALONG Lx MID-SPAN SUPPORT
a)
Coefficient α (IS456)
0.0403
0.0534
b)
Mu = 1.5 (α.w.Lx.Lx)
1375.70
1822.88
c)
Effective depth, d in mm
110
110
d)
K = Mu / b.d.d in N/sqmm.
1.1369
1.5065
e)
Percentage of Reinf. 'pt'
0.3439
0.4663
f)
Area of Reinforcement 'Ast'
378.33
512.94
g)
'Ast' minimum @ 0.12%
168.00
h)
Provide dia. & spacing as (T indicates HYSD bars - Fe415 gr.)
i)
Area of Steel provided, Ast(pr.)
j)
pt (pr.) = 100 Ast(pr.) / b.d
T 10.00 @ 140.00 mm c/c 561.00 0.5100
DEFLECTION CHECK :- (REF. CLAUSE 23.2.1 OF IS:456) Basic Allowable 'Lx/d' ratio without modification Steel Stress of Service Loads is given as fs = 0.58.fy [ Ast / Ast(pr.) ] Modification factor as per SP:24 (Clause 22.2) 1
= = =
26 162.32 N/mm2 1
=
0.225+0.00322.fs-0.625 log10(bd/Ast(pr)) Permissible 'Le/d' ratio with modification factor Actual Span/Depth ratio, Lx / d
