7.0.0
7.0.0 DETADETAILED ILED STRUCSTRUCTURATURAL L CALCALCULACULATIONSTIONS 7 7..11..00 DDaattaa Conversion factors Conversion factors 1 1NN//ssqqmmmm== ppssii 114455 1 1ppoouunndd== NN 44..4455 L Leennggtthh mm 33..0000 W Wiiddtthh mm 22..0000 h heeiigghhtt mm 33..5500 E
Eaarrtth h ccoovveer r oovveer r ttoop p ssllaabb mm 00..2200 S
Sooiil l ddeennssiittyy kkNN//ccuumm 1199 Angle of internal friction for soil
Angle of internal friction for soil degreesdegrees 3030 As per soil reportAs per soil report Coeff of earth pressure at rest = 1- sin
Coeff of earth pressure at rest = 1- sin ff 0.500.50 D
Deennssiitty y oof f wwaatteer r kkNN//ccuumm 1100 D
Deennssiitty y oof f ccoonnccrreettee kkNN//ccuumm 2255 L
Liivve e llooaad d oon n rrooooff kkNN//ssqqmm 55 f
f cc', specified compressive strength', specified compressive strength NN//ssqqmmmm 2255
o
of f ccoonnccrreette e GG330 0 ccuubbe e ssttrreennggtthh ppssii 33662255 (equivalent to G25 cylinder strength)
(equivalent to G25 cylinder strength) Y
Yiieelld d ssttrreennggtth h oof f rreebbaar r ppssii 6600000000 N
N//ssqqmmmm 441144 Allowable bearing pressure ( net )
Allowable bearing pressure ( net ) kN/sqmkN/sqm 100100 Allowable bearing pressure ( gross) at
Allowable bearing pressure ( gross) at founding level = net bearing pr + founding level = net bearing pr + ggdd
k
kNN//ssqqmm 116688 Strength reduction factor for flexure &
Strength reduction factor for flexure & tension
tension ff 0.900.90 As per As per cl. 9.3cl. 9.3.2.1.2.1
Strength reduction factor for shear
Strength reduction factor for shear ff 0.850.85 As per As per cl. 9.3cl. 9.3.2.3.2.3 Durability coefficient for flexure as per
Durability coefficient for flexure as per ACI 350
ACI 350 for water retaining structuresfor water retaining structures for limiting crackwidths
for limiting crackwidths
1.30
1.30 Reinforcement required to be Reinforcement required to be multiplied by this multiplied by this factor as per factor as per cl.9.2.8.1cl.9.2.8.1
Durability coefficient for direct tension Durability coefficient for direct tension as per ACI 350 for water retaining as per ACI 350 for water retaining structures for limiting crackwidths structures for limiting crackwidths
1.65
7.2.0 Assumed thickness
Top slab thickness m 0.15
Long wall thickness m 0.25
Short wall thickness m 0.25
Baseslab m 0.25
Base slab projection m 0.25
7.3.0 Weight calculations
Nos Length Breadth thickness Density Weight
m m m kN/cum kN
Topslab 1 3.50 2.50 0.15 25 32.81
Longwall 2 3.25 3.50 0.25 25 142.19
Shortwall 2 2.25 3.50 0.25 25 98.44
Baseslab 1 4.00 3.00 0.25 25 75.00
Soil cover above roof slab 1 3.50 2.50 0.20 19 33.25
Soil over base projection 1 13.00 3.85 0.25 19 237.74
(perimeter) (height)
Totalweight(DL) 619.43
waterweight 3.00 2.00 3.50 10 210.00
Live load on roof 3.50 2.50 5 43.75
(kN/sqmm)
Total live load (water+roof live load ) 253.75
7.4.0 Check for bearing capacity
Totalload 873.18 kN
Basearea 12.00 sqm
BearingpressduetoDL 51.62 kN/sqm
BearingpressduetoLL 21.15 kN/sqm
TotalBearingpressure 72.76 kN/sqm
7.5.0 Analysis & Design 7.5.1 Top slab
Dead load (DL)
Self weight of slab kN/sqm 3.75
Soil weight kN/sqm 3.80
TotalDL kN/sqm 7.55
Live Load(LL) kN/sqm 5.00
Loadfactor-DL 1.40
Loadfactor-LL 1.70
Factored total Load kN/sqm 19.07
Simply supported condition- coefficients from table 50 of Reynold's handbook
Span ratio Remarks
span support span support (ly/lx)
Effective span (clear+ wall thickness) m 1.44
Shear coeff 0.50 0.50 Max at the centre of span (approx)
Moment coeff ax3, ay3 0.548 0.126
Shear = Coeff x wlx kN/m 21.45 21.45
Moment Mu =Coeff *wl^2/8 kNm/m 6.62 3.18 generally
Partia fixity factors at span 1.00 0.25
Design Mu considering partial fixity kNm/m 6.62 6.62 3.18 3.18 Partia fixity factors at support 1 0.75
tension Tu kN/m 24.26 24.26 23.36 23.36 Overalldepth mm 150 150 150 150 clear cover mm 50 50 effective depth d mm 92 94 78 80 Allowable Shear = f x Vc Vc =2*fc'^0.5*b*d as per cl.11.3.1.1
kN/m 64.95 55.07 Safe as actual stress less than
allowable Ast from solving fMu = f [Ast x fy x d
(1-0.59 x r x (fy/fc'))], sqmm/m 270 264 151 147 Solving qua equation.
Ast for tension on each face = 1.65*Tu/( f f y)/ 2
sqmm/m 54 54 52 52
TotalAst sqmm/m 323 317 203 199
Min Ast per face(0.15% of gross area) sqmm/m 225 225 225 225 as per table 7.12.2.1 of ACI 350
Short span - lx Long span- ly
2.25 3.25
Shear from wall due water pressure ( from 7.5.2, b) & 7.5.3, b) )
7.5.2 Long wall
a) w ear ou s e+surc arge an
no water inside
earth pressure at top kN/sqm 3.32
earth pressure at bottom kN/sqm 38.94
Earth pressure due to surcharge load
of 20 kN/sqm (UDL) kN/sqm 2.50
The earth pressure due to soil weight is split up into two components-udl and triangular
udl kN/sqm 3.32
triangular kN/sqm 35.61 inside
Load Factor for Earth pressure 1.70 As per ACI 350
Load factor for surchage load 1.70 9.90 60.54
Factored loads
udl (soil+surcharge) kN/sqm 9.90
triangular kN/sqm 60.54
Slab fixed at sides& bottom, top hinged
Walls analysed using Moody's charts- fig 10 for udl and fig 13 for triangular
Span ratio Remarks
span support span support (a/b)
Effective span (clear+ wall thickness) 0.4392 Coefficients corresponding to a/b=1.0 are
udl taken
Shearcoeff-top 0.4020
Shear coeff - bottom 0.5980
shear coeff -sides 0.5491
Moment coeff 0.0617 0.1093 0.0227 0.0664
Shear - top kN/m 14.72
Shear - bottom kN/m 21.90
Shear-sides kN/m 20.11
Moment Mu kNm/m 8.36 14.81 3.08 9.00
tension kN/m Notensionunderthiscondition
triangular load
Shear coeff - top 0.1102
Shear coeff - bottom 0.3988
shearcoeff-sides 0.2583
Moment coeff 0.0259 0.0593 0.0098 0.0289
Shear-top kN/m 24.68
Shear-bottom kN/m 89.33
Shear-sides kN/m 57.86
Moment Mu kNm/m 21.47 49.15 8.12 23.95
tension kN/m Notensionunderthiscondition
Total
Shear-top kN/m 39.41
Shear - bottom kN/m 111.23
vertical span - b horizontal span- 2a
Shear-sides kN/m 77.97
Moment Mu kNm/m 29.83 63.96 11.20 32.95
Redistributed moment Mu kNm/m 49.39 44.39 32.96 Refer Moment distribution in Annex A
Design Moment Mu (higher of the two) kNm/m 49.39 63.96 11.20 32.96
tensionTu kN/m Notensionunderthiscondition
Overalldepth mm 250 250 250 250
clearcover mm 50 50
effectivedepth mm 94 90 74 74
Allowable Shear = f x Vc Vc
=2*fc'^0.5*b*d as per cl.11.3.1.1
kN/m 66.36 52.24 Safe as actual stress less than allowable
Ast from solving fMu = f [Ast x fy x d
(1-0.59 x r x (fy/fc'))], sqmm/m 2635 4608 598 2352 Solving qua.equation
Ast for tension on each face = 1.65*Tu/( f f y)/ 2
sqmm/m 0 0 0 0
Total Ast sqmm/m 2635 4608 598 2352
Min Ast per face(0.15% of gross area) sqmm/m 375 375 375 375 as per table 7.12.2.1 of ACI 350
b) with no earth outside and wate r inside
water pressure at bottom 35.00 kN/sqm
LoadFactor 1.70 AsperACI350 inside
Factored loads 59.50 kN/sqm
Slab fixed at sides& bottom, top hinged
Walls analysed using Moody's charts- fig 13 for triangular load 59.50
Span ratio Remarks
span support span support (a/b)
Effective span (clear+ wall thickness) 0.44 Coefficients corresponding to a/b=1.0 are
Shear coeff - top 0.1102 taken
Shear coeff - bottom 0.3988
shear coeff -sides 0.2583
Moment coeff 0.0259 0.0593 0.0098 0.0289
Shear-top kN/m 24.26
Shear-bottom kN/m 87.80
Shear-sides kN/m 56.86
Moment Mu kNm/m 21.10 48.30 7.98 23.54
Resistributed Moment Mu kNm/m 53.21 16.19 24.60 Refer Moment distribution in Annex A
Design Moment Mu (higher of the two) kNm/m 53.21 16.19 7.98 24.60
3.70 3.25
Tension kN/m 57.59 57.59 Overalldepth mm 250 250 250 250 clearcover mm 50 50 effectivedepth mm 94 90 74 74 Allowable Shear = f x Vc Vc =2*fc'^0.5*b*d as per cl.11.3.1.1 kN/m 66.36 52.24
Ast from solving fMu = f [Ast x fy x d
(1-0.59 x r x (fy/fc'))], 2990 710 416 1512 Solving qua.equation
Ast for tension on each face = 1.65*Tu/( f f y)/ 2
sqmm/m 0 0 128 128
Total Ast sqmm/m 2990 710 543 1640
Min Ast per face(0.15% of gross area) sqmm/m 375 375 375 375 as per table 7.12.2.1 of ACI 350
7.5.3 Short wall
a) with earth outside and no water inside
earth pressure at top(mid depth of top
slab) kN/sqm 2.61 inside
earth pressure at bottom(mid-depth of
bottom slab) kN/sqm 37.75
Earth pressure due to surcharge load
of 20 kN/sqm (UDL) kN/sqm 2.50 8.69 59.73
The earth pressure due to soil weight is split up into two components-udl and triangular
udl kN/sqm 2.61
triangular kN/sqm 35.14
Load Factor for earth pressure 1.70
Load factor for surchage load 1.70
Factored loads
udl (soil+surcharge) kN/sqm 8.69
triangular kN/sqm 59.73
Slab fixed at sides& bottom, top hinged
Walls analysed using Moody's charts- fig 10 for udl and fig 13 for triangular
Shear from short wall due water pressure (from 7.5.3, b) )
Span ratio Remarks
span support span support (a/b)
Effective span (clear+ wall thickness) 0.30 Coefficients corresponding to a/b=0.75
udl are taken
Shear coeff - top 0.3874
Shear coeff - bottom 0.5837
shear coeff -sides 0.5465
Moment coeff 0.0473 0.0898 0.0274 0.0695
Shear - top (kN/m) kN/m 12.45
Shear - bottom (kN/m) kN/m 18.76
Shear-sides(kN/m) kN/m 17.57
Moment Mu (kNm/m) kNm/m 5.63 10.68 3.26 8.27
tension kN/m Notensionunderthiscondition
triangular load
Shear coeff - top 0.1061
Shear coeff - bottom 0.3828
shear coeff -sides 0.2616
Moment coeff 0.0198 0.0505 0.0119 0.0302
Shear-top kN/m 23.45
Shear-bottom kN/m 84.60
Shear-sides kN/m 57.82
Moment Mu (kNm/m) kNm/m 16.19 41.30 9.73 24.70
tension kN/m Notensionunderthiscondition
Total Load
Shear-top kN/m 35.90
Shear - bottom kN/m 103.37
Shear-sides kN/m 75.38
Moment Mu (kNm/m) kNm/m 21.82 51.98 12.99 32.96
Redistributed Moment Mu kNm/m 43.69 30.11 Refer Moment distribution in Annex A
Design Moment Mu (higher of the two) kNm/m 43.69 51.98 12.99 32.96
tension kN/m Notensionunderthiscondition
Overalldepth mm 250 250 250 250
clearcover mm 50 50
effectivedepth mm 94 92 78 78
Allowable Shear = f x Vc Vc
=2*fc'^0.5*b*d as per cl.11.3.1.1 kN/m
66.36 55.07 Safe as actual stress less than allowable
Ast from solving fMu = f [Ast x fy x d
(1-0.59 x r x (fy/fc'))], sqmm/m 2191 3035 661 2081 Solving qua.equation
Ast for tension on each face = 1.65*Tu/( f f y)/ 2
sqmm/m 0 0 0 0
Total Ast sqmm/m 2191 3035 661 2081
Min Ast per face(0.15% of gross area) sqmm/m 375 375 375 375 as per table 7.12.2.1 of ACI 350
3.70 2.25
b) with no earth outside and wate r inside
water pressure at bottom 35.00 kN/sqm
LoadFactor 1.70
Factored loads 59.50 kN/sqm inside
Slab fixed at sides& bottom, top hinged
Walls analysed using Moody's charts- fig 13 for triangular load
59.50 Span ratio Remarks
span support span support (a/b)
Effective span (clear+ wall thickness) 0.30 Coefficients corresponding to a/b=0.75
Shearcoeff-top 0.1061 aretaken
Shear coeff - bottom 0.3828
shearcoeff-sides 0.2616
Moment coeff 0.0198 0.0505 0.0119 0.0302
Shear-top kN/m 23.36
Shear-bottom kN/m 84.27
Shear-sides kN/m 57.59
Moment Mu (kNm/m) kNm/m 16.13 41.14 9.69 24.60
Resistributed Moment Mu kNm/m 49.58 7.69 Refer Moment distribution in Annex A
Design moment kNm/m 49.58 7.69 9.69 24.60 tension kN/m 56.86 56.86 Overalldepth mm 250 250 250 250 clearcover mm 50 50 effectivedepth mm 94 92 78 78 Allowable Shear = f x Vc Vc =2*fc'^0.5*b*d as per cl.11.3.1.1 kN/m 66.36 55.07
Ast from solving fMu = f [Ast x fy x d
(1-0.59 x r x (fy/fc'))], sqmm/m 2650 315 482 1391 Solving qua.equation
Ast for tension on each face = 1.65*Tu/( f f y)/ 2
sqmm/m 0 0 126 126
Total Ast sqmm/m 2650 315 607 1516
Min Ast per face(0.15% of gross area) sqmm/m 375 375 375 375 as per table 7.12.2.1 of ACI 350
vertical span - b horizontal span- 2a
Shear from long wall due water pressure (from 7.5.2, b) )
7.5.4 Bottom slab
a) with earth outside and no water inside
Dead load (DL)
Self weight of slab 6.25 kN/sqm
Loadfactor 1.40
Factored DL due to self weight 8.75 kN/sqm
Soil pressure due to Dead loads 51.62 kN/sqm
Soil pressure due to live load on roof 3.65 kN/sqm
Factored Bearing pressure 78.46 kN/sqm
Net upward factored bearing pressure ( Soil pressure - slab self weight)
69.71 kN/sqm
Base slab support condition - All four sides fixed based onfig 34 of Moody's chart
Span ratio Remarks
span support span support (a/b)
Effective span (clear+ wall thickness) 0.69 Coefficients corresponding to a/b=0.625
Shear coeff 0.5143 0.4648 are taken
Moment coeff 0.0376 0.0765 0.0159 0.0547
Shear kN/m 80.67 72.91
Moment Mu kNm/m 13.27 27.00 5.61 19.31
Redistributed moment Mu kNm/m -4.12 44.39 -5.19 30.11
tension Tu kN/m 0.00 0.00 No tension under this condition
Overalldepth mm 250 250 250 250
clear cover mm 50 75
effective depth d mm 192 167 178 151
Allowable Shear = f x Vc Vc
=2*fc'^0.5*b*d as per cl.11.3.1.1 kN/m 135.55 125.67 Safe as actual stress less than allowable
Ast from solving fMu = f [Ast x fy x d
(1-0.59 x r x (fy/fc'))], sqmm/m -78 1030 -106 764 Solving qua equation
Ast for tension on each face = 1.65*Tu/( f f y)/ 2
sqmm/m 0 0 0 0
TotalAst sqmm/m -78 1030 -106 764
Min Ast per face(0.15% of gross area) sqmm/m 375 375 375 375 as per table 7.12.2.1 of ACI 350
2.25 3.25
b) with no earth outside and water inside
Dead load (DL)
Self weight of slab kN/sqm 6.25
Loadfactor 1.40
Factored DL due to self weight kN/sqm 8.75
Soil pressure due to Dead loads
(without soil load ) kN/sqm 29.04
Soil pressure due to live loads kN/sqm 0.00
Factored Bearing pressure kN/sqm 40.65
Net upward factored bearing pressure ( Soil pressure - slab self weight)
kN/sqm 31.90
Base slab support condition - All four sides fixed based on fig 34 of Moody's chart
Span ratio Remarks
span support span support (a/b)
Effective span (clear+ wall thickness) 0.69 Coefficients corresponding to a/b=0.692
Shear coeff 0.5143 0.4648 are taken
Moment coeff 0.0376 0.0765 0.0159 0.0547
Shear kN/m 36.92 33.36
Moment Mu kNm/m 6.07 12.35 2.57 8.83
Redistributed moment kNm/m 34.62 -16.19 19.09 -7.69 Minus sign indicates tension on inner face
tension Tu kN/m 87.80 87.80 84.27 84.27
Overalldepth mm 250 250 250 250
clear cover mm 50 75
effective depth d mm 192 167 178 151
Allowable Shear = f x Vc Vc
=2*fc'^0.5*b*d as per cl.11.3.1.1 kN/m 135.55 125.67 Safe as actual stress less than allowable
This portion should be hidden fMn = f [ As x fy x d (1-0.59 x p x (fy/ f' c))]
Short span-top Long Span
Top Bottom Top Bottom
M M(kN-m) = 34.62 16.19 19.09 -7.69 b b(in) = 39.37 39.37 39.37 39.37 d d(in) = 7.56 6.57 7.01 5.94 a a = 9.765517 9.765517 9.76552 9.76552 b b = -1 -1 -1 -1 c c = 0.0034 0.0021 0.002 -0.001 r r = 0.0035 0.0022 0.0022 -0.0012
As(req.) As(req.) in sq in. = r x b x d r x b x d r x b x d r x b x d
= 1.054 0.559 0.619 -0.284
2.25 3.25
Short span - a
Shear from wall due water pressure (from 7.5.2, b) & 7.5.3, b))
Water load not considered as it cancels each other while calculating the net upward pressure
As(req.) As(req.) mm2 = 680 361 399 -183
Ast from solving fMu = f [Ast x fy x d
(1-0.59 x r x (fy/fc'))], sqmm/m 680 361 399 -183 Solving qua equation
Ast for tension on each face = 1.65*Tu/( f f y)/ 2
sqmm/m 194 194 187 187
TotalAst sqmm/m 874 555 586 187