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2, Hence One Way Slab

1) The document provides the design of steel reinforcement and shear capacity check for a singly reinforced one way slab and a two way slab using limit state design method. 2) For the one way slab, the steel reinforcement provided at the support and span meets the requirement for moment and shear capacity. 3) For the two way slab, the steel reinforcement provided at the support and spans in both directions meets the requirement for moment capacity in both directions. The slab also satisfies the check for shear capacity.

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701 views6 pages

2, Hence One Way Slab

1) The document provides the design of steel reinforcement and shear capacity check for a singly reinforced one way slab and a two way slab using limit state design method. 2) For the one way slab, the steel reinforcement provided at the support and span meets the requirement for moment and shear capacity. 3) For the two way slab, the steel reinforcement provided at the support and spans in both directions meets the requirement for moment capacity in both directions. The slab also satisfies the check for shear capacity.

Uploaded by

ashn_604
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as XLS, PDF, TXT or read online on Scribd
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5 Design for area of steel and shear for singly reinforced one way slab by limit state design

method
Slab Geometry
Lx Ly Ly/Lx Result
m m
2.2 7.5 3.409 >2, Hence one way slab

Grade of concrete, steel, overall depth of slab & limiting resistance of moment of the slab
fy fck b D Cc Cg of bar d Mu lim pt lim
N/mm 2
N/mm 2 mm mm mm mm mm kN.m %
415 25 1000 160 25 6 129 57.41 1.19

Load calculation of the slab


Partial
Total
Dead Floor Live load Misc. load safety Design
unfactore
Load of finish of of the of the factor load of
d load of
the slab the slab slab slab the slab
the slab gf
DL FF LL ML TL Table 18 w
kN/m2 kN/m2 kN/m2 kN/m2 kN/m2 IS 456-2000 kN/m2
4 1 30 5 40 1.5 60

Moment & Shear calculation


Considering '1m' strip of the slab
w Lx w Lx2 Mu support 'kNm' Mu span 'kNm' Vu 'kN'
kN/m 2
m kNm Coef-support C w Lx 2 Coef-span C w Lx 2
Coef-shear C w Lx
60 2.2 290.4 0.100 29.040 0.083 24.103 0.500 66

Calculation of Ast req for slab


Ref IS 456-2000 Cl G-1.1b & G-1.1c For sections without compression reinforcement
Mu support Ast req.spt pt req.spt Mu span Ast span pt req.span check for depth
kNm mm2 % kNm mm2 % d req mm d prov mm Result
29.04 684.03 0.53 24.10 557.81 0.43 91.75 129 okay

Reinforcement details provided at support and span of slab


Reinf. details at support Reinf. details at span
dia prov. spacing Ast support pt support Result dia prov. spacing Ast span pt span
mm mm mm2 % mm mm mm2 %
12 150 12 150
753.98 0.58 okay 753.98 0.58
0 150 0 150

Check for shear in solid slabs for limit state design method
Ref IS 456-2000 Cl 40.1, Cl 40.2.3, Table 19, Table 20 & Cl 40.2.1.1

fck Vu b D clear cg d
N/mm 2
kN mm of slab mm cover mm of bar mm mm
25 66 1000 160 25 6 129

pt tv k tc tc max
Result
Cl 40.1 Cl 40.2.1.1 Table 20
% N/mm2 N/mm2 N/mm2 tau_v < k tau_c, Ok
0.58 0.51 0.67 3.1 tau_v <1/2 tau_c max,Ok

Check for span to depth ratio


Ref IS 456-2000 Cl 23.2.1
Type of fy span d pt req. pt prov. pc MFt MFc
beam N/mm 2 mm mm % % %
S.S.Slab 415 2200 129 0.43 0.58 0 1.532 1
l/d l/d Result
prov Cl 23.2.1 Cl 23.2.1
17.05 30.64 Okay

6 Design for area of steel and shear for two way slab by limit state design method
Slab Geometry
Lx Ly Ly/Lx Result
m m
2.12 3.02 1.425 <2, Hence two way slab

Grade of concrete, steel, & overall depth of slab


fy fck b D
N/mm2 N/mm2 mm mm
415 30 1000 150

Lx-shorter span
Cc bot Cg of bot bar d bot Cc top Cg of top bar d top
mm mm mm mm mm mm
25 4 121 25 4 121

Ly-longer span
Cc bot Cg of bot bar d bot Cc top Cg of top bar d top
mm mm mm mm mm mm
25 12 113 25 12 113

Load calculation of the slab


Partial
Total
Dead Floor Live load Misc. load safety Design
unfactore
Load of finish of of the of the factor load of
d load of
the slab the slab slab slab the slab
the slab gf
DL FF LL ML TL Table 18 w
kN/m2 kN/m2 kN/m2 kN/m2 kN/m2 IS 456-2000 kN/m2
3.75 1.25 15 0 20 1.5 30

Moment & Shear calculation


Moment calculation for '1m' strip of the slab spanning Lx
w Lx w Lx2 - Mux cont. edge 'kNm' + Mux mid-span 'kNm' Vu 'kN' Table 13 IS 456

kN/m 2
m kNm - ax - ax w L x
2 + ax + ax w L x
2
Coef-shear C w Lx
30 2.12 134.83 0.000 0.00 0.064 8.63 0.400 25.44

Calculation of Ast req for slab spanning Lx


Ref IS 456-2000 Cl G-1.1b & G-1.1c
- Mux cont. Ast min pt req.cont. + Mux span Ast span pt req.span
kNm mm 2 % kNm mm2 %
0 180.00 0.15 8.63 202.30 0.17

Reinforcement details provided at support and span of slab spanning Lx


Reinf. details at support Reinf. details at span
dia prov. spacing Ast cont. pt cont. Result dia prov. spacing Ast span pt span
mm mm mm 2
% mm mm mm2 %
8 250 8 150
201.06 0.17 okay 335.10 0.28
0 250 0 150

Moment calculation for '1m' strip of the slab spanning Ly


w Lx w Lx2 - Muycont. edge 'kNm' + Muy mid-span 'kNm'
kN/m2 m kNm - ay - ay w L x
2 + ay + ay w Lx2
30 2.12 134.83 0.045 6.07 0.035 4.72

Calculation of Ast req for slab spanning Ly


Ref IS 456-2000 Cl G-1.1b & G-1.1c
- Muy cont. Ast min pt req.cont. + Muy span Ast min pt req.span
kNm mm 2 % kNm mm 2
%
6.07 180.00 0.16 4.72 180.00 0.16

Reinforcement details provided at support and span of slab spanning Ly


Reinf. details at support Reinf. details at span
dia prov. spacing Ast cont. pt cont. Result dia prov. spacing Ast span pt span
mm mm mm 2
% mm mm mm2 %
8 250 8 250
201.06 0.18 okay 201.06 0.18
0 250 0 250

Check for shear in solid slabs for limit state design method
Ref IS 456-2000 Cl 40.1, Cl 40.2.3, Table 19, Table 20 & Cl 40.2.1.1

fck Vu b D clear cg d
N/mm 2
kN mm of slab mm cover mm of bar mm mm
30 25.44 1000 150 25 4 121

pt tv k tc tc max
Result
Cl 40.1 Cl 40.2.1.1 Table 20
% N/mm2 N/mm2 N/mm2 tau_v < k tau_c, Ok
0.28 0.21 0.51 3.5 tau_v <1/2 tau_c max,Ok
Check for span to depth ratio
Ref IS 456-2000 Cl 23.2.1
Type of fy span d pt req. pt prov. pc MFt MFc
beam N/mm 2 mm mm % % %
S.S.Slab 415 2120 121 0.17 0.28 0 2.904 1

l/d l/d Result


prov Cl 23.2.1 Cl 23.2.1
17.52 58.08 Okay
design method

Result

okay
Result

okay

Result

okay

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