all type of footing design
TRANSCRIPT
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Isolated Footing by Limit State Method
Data Required/assumed
Safe Bearing Capacity of the soil = 50 KN/m2 P = 87 Kn
M20 fck = 25 N/mm2 Mx = 0 Kn-m
FE415 Fe = 415 N/mm2 My = 0 Kn-m
Depth of soil above footing = 1.1 m Zx = 0.56 m3
Provide Overal Depth of footing = 350 mm Zy = 0.56 m3d = 300 mm net soil reaction = 38.67 KN/m2
Min Eff. depth required = 50 mm net soil reaction = 38.666667
Footing dimensions Considering only loads
B = 1.5 m
L = 1.5 m
Column dimensions
a = 500 mm
b = 500 mm
Load from Column = 87 KN
Net soil reaction = 38.67 KN/m2
B. M. at the face of column =
x = 0.5 Mxx = 7.250 KN-m/m length
y = 0.5 Myy = 7.250 KN-m/m length
Xumax = 144 mmMulimit = 310.42 Kn-m
Mulimit>M, Hence Section is Under reinforced
Designing as Under reinforced section xu=0.87.fy.Ast/0.36.fck.b
Astx = 67.22 mm2
Asty = 67.22 mm2
Ast min = 420 mm2 Astlimit= 3589.53 mm2
Provide Astx 10 mm bar @ 180 mm C/C AstxW.S.M 77.83 mm2
Provide Asty 10 mm bar @ 180 mm C/C 44.4E+6 KN-M
420.00 mm2
Check for One Way Shear
420.00
Factored Shear Vu = 11.60 KN
Tv = 0.039 p = 0.140
Tc = 0.282 From Code Using formula
Tv
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Isolated Footing by Limit State Method (To b Modify)
Data Required/assumed
Safe Bearing Capacity of the soil = 90 KN/m2 P = 40
M20 fck = 20 N/mm2 Mx = 10
FE415 Fe = 415 N/mm2 MZ = 15
Depth of soil above footing = 1.5 m Zx = 4.97Provide Overal Depth of footing D = 500 mm Zz = 4.97
d = 442 mm 9.20T 250 mm Net soil reaction = 4.16
Footing dimensions L = 3.1 m
B = 3.1 m Astlimit = 4230.86
Column dimensions a = 300 mm AstxW.S.M = 184.04
b = 500 mm M.R = 152.0E+6
CALCULATIONS
Load from Column = 40 KN
Net soil reaction = 9.20 KN/m2
B. M. at the face of column Mxx = 25.26 KN-m/m length
Myy = 30.20 KN-m/m length
dxxreq = 95.66 mm
dyyreq = 104.60 mm 16.84
Astx = 159.55 mm2
Asty = 191.02 mm2
Ast min = 1000 mm2
Provide Astx 1000.00 mm2 16 mm tor @ 200 mm C/C
Provide Asty 1000.00 mm2 16 mm tor @ 200 mm C/C
Check for One Way Shear
Factored Shear Vu = 11.84 KN
Tv = 0.027 p = 0.226
Tc = 0.344 From Code Using formula
Tv
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Kn
Kn-m
Kn-m
m3m3
KN/m2
KN/m2
mm2
mm2
KN-M
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Combined Footing by Limit State Method
Safe Bearing Capacity of the soil = 80 KN/m2 W1= 450 KN
M20 fck = 20 N/mm2 W2= 100 KN
Fe415 Fe = 415 N/mm2 Mx= 90 KN-m
Provide Overal Depth of footing D = 500 mm Mz= 100 KN-m
d = 440 mm a1= 1 mDepth above footing = 1.55 m C= 3 m
Footing dimensions Af= 7.56 m2
B = 2.50 m x-= 0.545 m
L = 7.00 m L= 3.1 m
Column dimensions a1 = 600 mm B= 2.45 m
a2 = 600 mm a2= -0.9 m
b1 = 500 mm s1= 0.700 m
b2 = 500 mm s2= -1.209 m STRES
Net soil reaction = 49.55 KN/m2 Zx= 20.417 m3
UDL for long. BM= R.B 185.82 KN/m2 Zz= 7.292 m3
UDL for Trans. BM=R.1 74.33 KN/m2
Longitudinal BMDM1= w.s1 /2 M1 = 45.53 KN-m
M2=w.s2 /2 M2 = 677.30 KN-m
x= 3.63 Mx = 551.01 KN-m
Xumax = 211.2 Mulimit = 1335.49 Kn-m
Longitudinal Steel Astmin = 880 mm2
Ast1 = 880 mm2 16 @220 C/C > Astmin
Ast2 = 2978 mm2 16 @60 C/C > Astmin
Top Ast = 1494 mm2 16 @130 C/C Or 24 Nos
> Astmin
Transverse steel
t1 = 1 Mt1 = 37.16 KN-m 1493.2
t2 = 1 Mt2 = 37.16 KN-m
Astmin = 1000 mm2
AstT1 = 1000 mm2 16 @200 C/C Min.Steel
AstT2 = 1000 mm2 16 @200 C/C > Astmin
Design of shear Two Way Shear (Punching)
Critical section 1 Under column 1
x1=s1+b1+d = 1.74 Tvv 0.2166
V1 = 126.68 p = 0.1358 Tcc 1.1180
Tv = 0.1152 Tvv < Tcc hence safe
Tc = 0.2751 Tv
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COMBINED FOOTING DESIGN BY SURAJ
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88.99445
t1 t2
s1d d d2
ast1 ast2
Ast
Transeverse steel
a2
s2
c
a2
s2
c
Top level steel
Bottom level steel
Ast2
Ast1AstT1
Ast
W1W2c
W1+W2x-
COMBINED FOOTING DESIGN BY SURAJ
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0.287509 0.15
COMBINED FOOTING DESIGN BY SURAJ
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COMBINED FOOTING DESIGN BY SURAJ
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COMBINED FOOTING DESIGN BY SURAJ
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Combined Footing Using Limit State Method
Data Required/assumed W1 800 KN
Safe Bearing Capacity of the soil = 90 KN/m2 W2 1410 KN
M20 fck = 20 N/mm2 W3 1350 KN
FE415 Fe = 415 N/mm2 Mx1 0.98 KN-m
Provide Overal Depth of footing = 600 mm Mx2 9.67 KN-md = 540 mm Mx3 9.59 KN-m
Depth above footing = 2.5 m Mz1 2.88 KN-m
Footing dimensions Mz2 6.93 KN-m
B = 3 m Mz3 2.66 KN-m
L = 18.3 m Af 43.51 mm2
Column dimensions a1 1.5 m
b1 = 700 mm c1 6.2 m
b2 = 700 mm c2 6.2 m
l1 = 700 mm x- 7.158 m
l2 = 700 mm L 17.3 m
Net soil reaction = 66.91 KN/m2 B 2.51 m
UDL for long. BM= R.B 301.10 KN/m2 a2 3.4 mUDL for Trans. BM=R.1 100.37 KN/m2 s1 1.150 m
s2 3.066 m
Zx 167.445 m3
Longitudinal BMD M1= w.s12/2 199.10 KN-m Zz 27.450 m3
M2=w.s22/2 2469.42 KN-m
M3 1414.99 KN-m
x= 2.66 Mx 137.24 KN-m
Xumax = 259.2 Mulimit = 804.60 Kn-m
Mxx and Myy>Mulimit, Hence Section is over reinforced
Transeverse steel
t1 = 1.15 Mt1 66.37 KN-m
t2 = 1.15 Mt2 66.37 KN-md trans
Longitudinal Steel Astmin = 1200 mm2
Ast1 = 1200 mm2 > Astmin 20
Ast2 = 15918 mm2 > Astmin 20
Top Ast = 1200 mm2 > Astmin 20
Top No.of bars 12 11
Transverse steel Astmin = 1200 mm2
AstT1 = 1200 mm2 Provide Minimum Steel 20
AstT2 = 1200 mm2 Provide Minimum Steel 20
Design of shear
Critical section 1
x1=s1+b1+d = 2.39
V1 = 80.36 p = 0.074074
Tv = 0.0496
Tc = 0.2090
Tv
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x2=s2+b2+d = 4.3057303
V2 = 113.53
Tv = 0.0701
Tv
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944.1
51.225
240.435
69.2246812
15
@260 C/C
@10 C/C
@260 C/C
@260 C/C
@260 C/C
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t1 t2
s1d d d2
ast1 ast2
Ast
Transeverse steel
a2
s2
c
a2
s2
c
Top lev
Bottom
Ast2
Ast1AstT1
Ast
W1 W2c
W1+W2x-
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el steel
level steel
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Combined Footing by Limit State Method (beam slab)
Data Required W1 800 KN
Safe Bearing Capacity of the soil = 150 KN/m2 W2 800 KN
M20 fck = 15 N/mm2 Mx 4.5 KN-m
FE415 Fe = 250 N/mm2 Mz 4.5 KN-m
Width of beam b = 400 mm a1 1.4 m
Column dimensions b1 = 400 mm c 4.2 m
b2 = 400 mm depth 2.5 m
l1 = 400 mm
l2 = 400 mm
Af 11.73 mm2
x- 2.1 m
Footing dimensions L 7 m
B = 1.7 m B 1.7 m
L = 7 m a2 1.4 m
Size is adequate w.r.t S.B.C s1 1.2 m
Net soil reaction = 136.36 KN/m2 s2 1.2 m
UDL for long. BM= R.B 228.57 KN/m2 Zx 3.28 mm3
UDL for Trans. BM=R.1 136.36 KN/m2 Zz 13.69 mm3
Slab is designed to resist transeverse bending
Transeverse steel
t1 = 0.638 Mt1 41.64 KN-m
t2 = 0.638 Mt2 41.64 KN-m
d Reqd = = 136.96 mm
Provide Overal Depth of footing D = 190 mm
d = 144 mm
Xumax = 76.32 Mulimit = 46.14 Kn-m M Astmin
AstT2 = 1482 mm2 > Astmin
Astmin = 285 mm2
Provide Distribution steel of Astmin 8 mm bar @ 170 mm C /C
Design of beam
Longitudinal BMD M1= w.s12/2 246.86 KN-m b = 400
M2=w.s22/2 246.86 KN-m d = 534
M3 246.86 KN-m D = 590
Xumax = 283.02 Mulimit = 253.78 Kn-m
M Astmin
Ast2 = 2692 mm2 > Astmin
x= 3.5 Mx = 280.00 KN-m
Top steel is to resist BM of 280.00 KN-m as inverted T-beam Action
Lo = 3.13 mbf = 0.934 m
Mulimit = 592.27 Kn-m
M Mx: Section is safe under Bending
Design of shear
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Critical section 1
x1=s1+b1+d = 2.134
V1 = 68.34
Tv = 0.3200
Tc = 0.2033 Tv>Tc Design for shear
Providing 2-legged 8 150mm C/C
Critical section 2
x2=s2+b2+d = 2.134 Min. spacing is lesser of following
V2 = 68.34 a. Asv/b.Sv=0.4/fy
Tv = 0.3200 b. 0.75*d
Providing 2-legged 8 150mm C/C c. 450mm
Critical section 3 d. 0.87.fy.Asv.d/(Tv-Tc)b.d if Tv>Tc
x3=s2-d2 = 0.666
V3 = 152.23
Tv = 0.1701
Tc = 0.2033 Tv
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Strap Footing:
Data Required
Safe Bearing Capacity of the soil SBC = 150 KN/m2
Allowable stress in Concrete M20 fck = 15 N/mm2
Allowable stress in steel Fe 415 Fy = 415 N/mm2
Width of beam b = 400 mm
Column sizes b1 = 300 mm
b2 = 400 mm
b3 = 0 mm
Loads from columns W1 = 600 KN
W2 = 900 KN
W3 = 0 KN
L1 = 3 m
a1 = 0.15 m
Distance bet columns c = 5 m
Area of footing Af = 11.00 m2
CG of fooing x- = 2 m
Footing dimensions L2 = 2.475 m
B = 2.0 m
a2 = 1.2375 m
Gap = 0.9125 m
s1 = 0 m
s2 = 1.0375 m
Net soil reaction R = 136.36 KN/m2
UDL for long. BM= R.B wLong = 273.97 KN/m2
UDL for Trans. BM=R.1 wTrans = 136.36 KN/m2
Design of Cantilever Slab
Cantilever projection x = 0.80 m
Max. Bm in Slab Mmax = 66.20 KN-m
Dreq = 230 mm
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L2
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d = 184 mm
xumax = 121.92 mm
Mulimit = 167.23 KN-m MTc, Design of shear is reqd., Increase Depth of footing to, d = 254
Provide Overal depth of footing 300 mm
Ast = 791 mm2 12 mm bar @ 90
Astmin = 360 mm2 8 mm bar @ 130
Design of Beam
Max BM Mmax = 850.50 KN-m x = 2.19 m
BM at end of footing M = 715.68 KN-m x = L1 =3 m
BM corresponding to s2 M2 = 221.18 KN-m x = 5.35 m
BM at the end of right side footing M = 411.93 KN-m x = 3.9125 mMulimit = 715.95 KN-m xumax = 446.4
Depth req. as per T-beam action d =
Depth req. as/ rect. beam action d = 930 mm
Provide overall depth of steel D = 1000 mm
Area of steel
Top steel in beam Ast = 3388 mm2
Astmin = 762 mm2
Provide 12 Nos 20 TOR in two row, total Ast= 3770 mm2
steel at bottom Ast = 762 mm2
Provide 4 Nos 20 TOR total ast= 1257 mm2Check for moment of resitance MR = IF((0.87*E17*I53/(0.36*E16*F4 bf= Lo/(Lo/b+4)+bw
Area of side face steel Astside = 400 mm2
Provide 3 Nos 10 TOR bar in each face BUT spacing
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G1
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m
mm C/C As main steel
mm C/C as distribution
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Isolated Circular Footing by Limit State Method
Data Required/assumed
Safe Bearing Capacity of the soil = 80 KN/m2 P = 517.4
M20 fck = 20 N/mm2 Mx = 25
FE415 Fe = 415 N/mm2 Zx = 5.18
Depth of soil above footing h = 1.5 m 51.68Provide Overal Depth of footin D = 700 mm Cons loads only 46.85
deff = 642 mm M.R = 654.70
T 300 mm Astlimit = 6145.28
Diameter of footing D = 3.75 m AstxW.S.M = 1807.40
Column dimensions d = 3.5 mm
CALCULATIONS side = 2.47 m Tv>Tc Unsafe
Load from Column = 517.4 KN
Upword soil pressure at face of column = 214.02 KN
B. M. at the face of column x = 1.12 m
Mxx = 240.19 KN-m
dxxreq = 187.71 mmAst = 1046.18 mm
2
Ast min = 3150 mm
Provide 16 Nos 16 mm tor in each direction at right angles to each oth
Check for One Way Shear
Factored Shear Vu = 755.18 KN
Tv = 0.291 p = 0.131
Tc = 0.271 From Code Using formula
Tv>Tc Unsafe
Check for Two Way Shear
Two way shear = 830.734 KN
Tvv = 0.638
Allowable shear = 1.118Tvv < Tcc hence safe
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Kn
Kn-m
m3
KN/m2KN/m2
KN-M
mm
mm
Data req for WSM
j 0.9
st 230
cbc 7
m 13.33
x1 0.29
j 0.90Q 0.91
%steel 0.439
er