Footing Design
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FOOTING FOR COLUMN (450 x 230)(F1) MAX M ZZ CASE INPUT DATA ( FACTORED LOADS) Node-LC Vertical Load = 814.426 kN Moment @x-x Mx = 21.816 kN-m Moment @y-y My = 2.673 kN-m =
25
kN/m3
= = =
21 20 415
kN/m3 Mpa Mpa
= =
1.8 1.8
m m
= =
0.3 0.3
m m
Depth of Founding lvl(H) Ht. of Pedestal above G.L.
= =
3 0
m m
Net S.B.C
=
250
kN/m2
Gross S.B.C. Load factor Clear cover to footing Dia of bar used Assumed depth of foundation
= = = = =
250 1.5 50 12 0.45
kN/m2
DESIGN CALCULATION (UNFACTORED LOADS) Direct load from footing Self weight of footing Dead weight of soil over footing Total vertical load Moment @x-x Mx Moment @y-y My
= = = = = =
543.0 36.5 120.5 699.9 14.5 1.8
KN KN KN KN kN-m kN-m
Area of footing required
=
2.17
m
Area of footing provided
=
3.24
m2
Unit wt. of conc.gc Unit wt. of soil gs Ch. Strength of conc. Yield Strength of steel SIZE OF FOOTING Length @ x-x ; Lx Length @ y-y ; Ly SIZE OF COLUMN Length @ x-x ; bx Length @ y-y ; by
NODES:-
2,5,6,8
Y Lx
My-y Mx-x Ly X
bx by
Mx-x My-y
X
by bx Y
Grade Level
mm mm m
1
2
1
2
D
2
O.K.
Zx-x
=
0.97
m2
Zy-y
=
0.97
m
P/ A
=
216.02
KN/m2
Mx-x / Zx-x
=
14.97
KN/m2
My-y / Zy-y
=
1.84
KN/m2
2
Gross maximum & minimun pressure under the footing are :1 Pmax
=
232.83
KN/m2
Pmin.
=
199.21
KN/m
Pgross at face of pedestal
=
218.82
KN/m2
Paverage at face of pedestal
=
225.83
KN/m
Pnet at face of pedestal
=
162.83
KN/m2
=
68.69
kN.m
2
O.K. NO TENSION
s Pmin. =
s' q s1
199.21
213.22
Pmax = 218.82
2
For 415 grade of steel.
Effective depth required
=
158
Effective depth Provided Mu / bd 2 % of steel required
= = =
394 0.44 0.125
mm
Ast required Dia of barto be used Ast required Min required Spacing of reinforcement Provide 12 % Ast provided
= =
561 12 540 201.53
mm
= mm dia bars@ = 0.140
mm Hence O.K
From SP-16 2
mm 180
Check for One way shear: Critical section is "d" from the face of the column. Pgross at 'd' from face of pedestal =
226.18
KN/m2
P average at 'd' from face of pedestal =
229.51
KN/m2
Pnet at 'd' from face of pedestal = Max shear at 'd' from face of pedestal = Tv =
166.51 88.91 0.23
KN/m kN Mpa
2
2
PRESSURE DIAGRAM ON SOIL
Structural design
M = 0.138 x f ck x b x d
q s2
2
1
Max moment at face of pedestal
2
mm C / C. in both the directions.
232.83
% of steel provided Tc
= =
0.14 0.28
Mpa > Tv (Table - 19 , IS - 456-2000 ) Hence SAFE FOR ONE WAY SHEAR
Check for two way shear: Critical section is considered at a distance d/2 from thr periphery of the face of the column or pedeatal. 2
Pgross at 'd/2' from face of pedestal =
222.50
KN/m
P average at 'd/2' from face of pedestal =
227.67
KN/m2
Pnet at 'd/2' from face of pedestal =
164.67
KN/m
BxL a+d b+d
= = =
2
2
3.24 0.694 0.694
m m m
681.31 2776 0.62
kN mm Mpa
a+d
b+d The max force V = p( BxL - ( a+d)(b+d)) = b o = 2((a+d) + (b+d)) = Shear stress Tv = V / b o .d =
b a L
Calculation of allowable shear stress:(CL:31.6.3.1 of IS-456) ks x Tc 1 ks =0.5 + beta beta 1 Tc =0.25sqrt(fck) Allowable shear stress Tc Tc =
= = = =
1 1.000 1.118033989 1.12
should not greater 1 shortside / long side of column or pedestal Mpa > Tv
Hence SAFE FOR TWO WAY SHEAR
B
FOOTING FOR COLUMN (450 x 230)(F1) MAX M ZZ CASE INPUT DATA ( FACTORED LOADS) Node-LC Vertical Load = 479.993 kN Moment @x-x Mx = 22.142 kN-m Moment @y-y My = 3.974 kN-m =
25
kN/m3
= = =
21 20 415
kN/m3 Mpa Mpa
= =
1.4 1.4
m m
= =
0.3 0.3
m m
Depth of Founding lvl(H) Ht. of Pedestal above G.L.
= =
3 0
m m
Net S.B.C
=
250
kN/m2
Gross S.B.C. Load factor Clear cover to footing Dia of bar used Assumed depth of foundation
= = = = =
250 1.5 50 12 0.3
kN/m2
DESIGN CALCULATION (UNFACTORED LOADS) Direct load from footing Self weight of footing Dead weight of soil over footing Total vertical load Moment @x-x Mx Moment @y-y My
= = = = = =
320.0 14.7 68.6 403.3 14.8 2.6
KN KN KN KN kN-m kN-m
Area of footing required
=
1.28
m
Area of footing provided
=
1.96
m2
Unit wt. of conc.gc Unit wt. of soil gs Ch. Strength of conc. Yield Strength of steel SIZE OF FOOTING Length @ x-x ; Lx Length @ y-y ; Ly SIZE OF COLUMN Length @ x-x ; bx Length @ y-y ; by
NODES:-
3,4,9,11,14,17,20
Y Lx
My-y Mx-x Ly X
bx by
Mx-x My-y
X
by bx Y
Grade Level
mm mm m
1
2
1
2
D
2
O.K.
Zx-x
=
0.46
m2
Zy-y
=
0.46
m
P/ A
=
205.77
KN/m2
Mx-x / Zx-x
=
32.28
KN/m2
My-y / Zy-y
=
5.80
KN/m2
2
Gross maximum & minimun pressure under the footing are :1 Pmax
=
243.85
KN/m2
Pmin.
=
167.69
KN/m
Pgross at face of pedestal
=
213.93
KN/m2
Paverage at face of pedestal
=
228.89
KN/m
Pnet at face of pedestal
=
165.89
KN/m2
=
37.64
kN.m
2
O.K. NO TENSION
s Pmin. =
s' q s1
167.69
197.61
Pmax = 213.93
2
For 415 grade of steel.
Effective depth required
=
117
Effective depth Provided Mu / bd 2 % of steel required
= = =
244 0.63 0.180
mm
Ast required Dia of barto be used Ast required Min required Spacing of reinforcement Provide 12 % Ast provided
= =
539 12 360 209.97
mm
= mm dia bars@ = 0.209
mm Hence O.K
From SP-16 2
mm 180
Check for One way shear: Critical section is "d" from the face of the column. Pgross at 'd' from face of pedestal =
227.20
KN/m2
P average at 'd' from face of pedestal =
235.53
KN/m2
Pnet at 'd' from face of pedestal = Max shear at 'd' from face of pedestal = Tv =
172.53 79.19 0.32
KN/m kN Mpa
2
2
PRESSURE DIAGRAM ON SOIL
Structural design
M = 0.138 x f ck x b x d
q s2
2
1
Max moment at face of pedestal
2
mm C / C. in both the directions.
243.85
% of steel provided Tc
= =
0.21 0.33
Mpa > Tv (Table - 19 , IS - 456-2000 ) Hence SAFE FOR ONE WAY SHEAR
Check for two way shear: Critical section is considered at a distance d/2 from thr periphery of the face of the column or pedeatal. 2
Pgross at 'd/2' from face of pedestal =
220.57
KN/m
P average at 'd/2' from face of pedestal =
232.21
KN/m2
Pnet at 'd/2' from face of pedestal =
169.21
KN/m
BxL a+d b+d
= = =
2
2
1.96 0.544 0.544
m m m
422.36 2176 0.80
kN mm Mpa
a+d
b+d The max force V = p( BxL - ( a+d)(b+d)) = b o = 2((a+d) + (b+d)) = Shear stress Tv = V / b o .d =
b a L
Calculation of allowable shear stress:(CL:31.6.3.1 of IS-456) ks x Tc 1 ks =0.5 + beta beta 1 Tc =0.25sqrt(fck) Allowable shear stress Tc Tc =
= = = =
1 1.000 1.118033989 1.12
should not greater 1 shortside / long side of column or pedestal Mpa > Tv
Hence SAFE FOR TWO WAY SHEAR
B
FOOTING FOR COLUMN (450 x 230)(F1) MAX M ZZ CASE INPUT DATA ( FACTORED LOADS) Node-LC Vertical Load = 336.502 kN Moment @x-x Mx = 19.743 kN-m Moment @y-y My = 2.927 kN-m =
25
kN/m3
= = =
21 20 415
kN/m3 Mpa Mpa
= =
1.2 1.2
m m
= =
0.3 0.3
m m
Depth of Founding lvl(H) Ht. of Pedestal above G.L.
= =
3 0
m m
Net S.B.C
=
250
kN/m2
Gross S.B.C. Load factor Clear cover to footing Dia of bar used Assumed depth of foundation
= = = = =
250 1.5 50 12 0.3
kN/m2
DESIGN CALCULATION (UNFACTORED LOADS) Direct load from footing Self weight of footing Dead weight of soil over footing Total vertical load Moment @x-x Mx Moment @y-y My
= = = = = =
224.3 10.8 45.9 281.1 13.2 2.0
KN KN KN KN kN-m kN-m
Area of footing required
=
0.90
m
Area of footing provided
=
1.44
m2
Unit wt. of conc.gc Unit wt. of soil gs Ch. Strength of conc. Yield Strength of steel SIZE OF FOOTING Length @ x-x ; Lx Length @ y-y ; Ly SIZE OF COLUMN Length @ x-x ; bx Length @ y-y ; by
1,7,10,12,13,15,16,18,19, 21,22,23,24
NODES:Y Lx
My-y Mx-x Ly X
bx by
Mx-x My-y
X
by bx Y
Grade Level
mm mm m
1
2
1
2
D
2
O.K.
Zx-x
=
0.29
m2
Zy-y
=
0.29
m
P/ A
=
195.19
KN/m2
Mx-x / Zx-x
=
45.71
KN/m2
My-y / Zy-y
=
6.78
KN/m2
2
Gross maximum & minimun pressure under the footing are :1 Pmax
=
247.68
KN/m2
Pmin.
=
142.70
KN/m
Pgross at face of pedestal
=
208.31
KN/m2
Paverage at face of pedestal
=
228.00
KN/m
Pnet at face of pedestal
=
165.00
KN/m2
=
25.06
kN.m
2
O.K. NO TENSION
s Pmin. =
s' q s1
142.70
182.07
Pmax = 208.31
2
For 415 grade of steel.
Effective depth required
=
95
Effective depth Provided Mu / bd 2 % of steel required
= = =
244 0.42 0.119
mm
Ast required Dia of barto be used Ast required Min required Spacing of reinforcement Provide 12 % Ast provided
= =
356 12 360 318.08
mm
= mm dia bars@ = 0.209
mm Hence O.K
From SP-16 2
mm 180
Check for One way shear: Critical section is "d" from the face of the column. Pgross at 'd' from face of pedestal =
229.66
KN/m2
P average at 'd' from face of pedestal =
238.67
KN/m2
Pnet at 'd' from face of pedestal = Max shear at 'd' from face of pedestal = Tv =
175.67 54.28 0.22
KN/m kN Mpa
2
2
PRESSURE DIAGRAM ON SOIL
Structural design
M = 0.138 x f ck x b x d
q s2
2
1
Max moment at face of pedestal
2
mm C / C. in both the directions.
247.68
% of steel provided Tc
= =
0.21 0.33
Mpa > Tv (Table - 19 , IS - 456-2000 ) Hence SAFE FOR ONE WAY SHEAR
Check for two way shear: Critical section is considered at a distance d/2 from thr periphery of the face of the column or pedeatal. 2
Pgross at 'd/2' from face of pedestal =
218.99
KN/m
P average at 'd/2' from face of pedestal =
233.33
KN/m2
Pnet at 'd/2' from face of pedestal =
170.33
KN/m
BxL a+d b+d
= = =
2
2
1.44 0.544 0.544
m m m
292.31 2176 0.55
kN mm Mpa
a+d
b+d The max force V = p( BxL - ( a+d)(b+d)) = b o = 2((a+d) + (b+d)) = Shear stress Tv = V / b o .d =
b a L
Calculation of allowable shear stress:(CL:31.6.3.1 of IS-456) ks x Tc 1 ks =0.5 + beta beta 1 Tc =0.25sqrt(fck) Allowable shear stress Tc Tc =
= = = =
1 1.000 1.118033989 1.12
should not greater 1 shortside / long side of column or pedestal Mpa > Tv
Hence SAFE FOR TWO WAY SHEAR
B
Node 24 13 22 10 16 1 18 12 19 21 15 23 7
Force-Y kN Moment-X kNm Moment-Z kNm 191.938 -14.209 2.554 203.267 -3.659 -0.032 204.143 6.348 2.334 204.668 -3.866 -0.113 228.156 2.498 -1.693 260.593 4.319 -2.927 276.786 -15.252 -0.485 281.241 -15.659 -0.102 284.383 7.706 1.838 296.023 -10.603 0.443 300.97 -19.743 -0.321 329.165 5.586 1.808 336.502 -1.638 2.023
4 3 14 11 17 9 20
364.721 390.185 442.814 443.681 464.299 478.081 479.993
-3.908 -22.142 13.558 11.623 3.71 -21.095 -1.223
-1.645 -3.974 -0.078 -0.384 -1.488 -0.223 2.165
6 2 8 5
549.36 644.235 764.428 814.426
-21.816 15.046 13.313 19.718
0.426 -2.547 2.504 -2.673
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