DESIGN OF AXIAL LOADED FOOTING FOR SQUARE COLUMN
load on column = 300 Kn
size of column = B= 0.23 D 0.23 m
SBC = 200 Kn/m2
Fck = 20 Kn/m2
Fy = 415 Kn/m2
load on footing = 330 Kn
area = 1.65 m2
size of footing = B= 1.3 D= 1.3 m
area provided = 1.69 m2
net upward pressure = 292.89940828 kn/m2
critical sec length = 0.535 m
B.M = 54.492836538 knm
depth of footing = 123.23767329 mm
taken depth = 277.28476491 mm
cover = 50
dia of bar = 10 ast. = 78.53981634
overall depth = 342.5
pt% = 0.1561337986 %
Ast req = 562.81580731 mm2
no. of steel = 8
Ast prov. = 628.31853072 mm2
pt% prov = 0.1743052659
clear spacing = 137.75 OK
check for onewayshear =
Vu = 98.130031822 kn
Tau v = 0.2722278661
Tau c (choose from table) = 0.29 OK
=
check for two way shear =
Vu = 419.62590107 kn
Tau v = 0.7458035866
Tau c(take from table) = 1.1180339887
kc = 1 for square column
Tau c'(kc*Tau c) = 1.1180339887
=
check (Tau v<Tau c') = ok
=
summary =
bar dia(mmno of bar spacing(mm)
along x dir 10 8 137.75
along z dir 10 8 137.75
mm2
Design of axial loaded rectangular column sloped footing
load on column = 500 Kn
size of column = B(mm)= 230 D(mm)= 300 mm
cover(mm) = 50 0.23 m 0.3 m
SBC = 200 Kn/m2
Fck = 20 N/mm2
Fy = 415 N/mm2
bar dia = 12 mm a,st 113.097336
load on footing = 550 Kn
factored load on footing= 750 Kn
area = 2.75 m2
size of footing = B= 1.5472951 D= 1.9 m
taken B= 1.6 m
area provided = 3.04 m2
upward pressure = 246.71052632 Kn/m2
critical length 0.8 m
B.M
along shorter span 150 Knm
along longer span 126.31578947 Knm
eff. depth(d)
along longer span = 347.04235442 mm
along shorter span = 347.52402343 mm
try overall depth(D=d+150)= 400 mm (put manually)
taken depth along longer span= 344 mm
taken depth along shorter span= 332 mm
taken avg depth(d) = 338 mm
Reinforcement
along longer span pt%= 1.0800797797 %
Ast= 1613.6391909
no of bar 15
Ast prov = 1696.4600329
pt% prov = 1.135515417 %
along shorter span pt%= 0.976112322 %
Ast= 1275.9740273
no of bar = 12
Ast prov = 1357.1680264
pt% prov = 1.0382252344 %
spacing
along longer dir
c/c = 127.71428571 mm
clear spacing = 115.71428571 mm OK if spacing is>180 ,change bar dia)
along shorter dir
c/c = 135.27272727
clear spacing = 123.27272727 Ok
check for oneway shear(at a dist d from face of support)
along longer span
l of critical sec = 456 mm
depth at critical sec 96.9 mm l
d' = 270.9 mm. = 0.2709 m 800
b' = 918 mm
Vu 180 kn
Tau v = 0.5943526781 N/mm2 mu= 41.04
Tau c (from table usingpt% along longer dir)pt%prov 1.135515417 %
Tau c = 0.65 N/mm2 OK (put manually)
check for twoway shear
length of critical sec = 631 mm
depth @ critical sec = 134.0875
d' = 296.0875 mm
b' = 2412 mm
Vu = 660.59605263 Kn
Tau v 0.9249933228 N/mm2
Tau c = 1.1180339887
ks = 1.2666666667
Tau c' = 1.4161763857
check(Tau v<Tau c')
Tau v < Tau c' OK
summary dia(mm) no.s spacing(in mm)
along longer span 12 15 115.7142857
along shorter span 12 12 123.2727273
180 ,change bar dia)
D
170 tanB= 0.2125
knm
design of Ecentric footing
load on column(Pu) = 513.33333333 Kn Pu= 770 kn
Mx = 110 kn-m Mux= 165 kn-m
My = 50 knm Muy= 75 kn-m
size of column = B= 0.3 D= 0.6 m
cover(mm) = 50 300 mm 600 mm
SBC = 200 Kn/m2
Fck = 25 N/mm2
Fy = 415 N/mm2
bar dia = 12 mm ast= 113.0973355 B L
load on footing = Kn 2.1 2.4
factored load on footing= Kn
area taken B= 2.1 D= 2.4 m
B.M @ face of column
for Mx =
length = 0.9 m
Pmax 156.41534392 kn/m2
Pmin 47.288359788 kn/m2
p 115.49272487 kn/m2
Mx 121.4296875 knm
Mux 182.14453125 knm
for My
Pmax 130.19652305 kn/m2
Pmin 73.50718065 kn/m2
P 105.90109059 kn/m2
My 118.67930029 knm
Muy 178.01895044 knm
depth of footing
dx 158.55826074 mm
dy 146.62835074 mm
D=(2-2.5)*d 500 mm
taken dx 444 mm
taken dy 432 mm
Avg d 438 mm
Reinforcement
along long dir
pt% req 0.124494408 %
Ast 1160.7858606 mm2
min Ast 1260 mm2
take Ast 1260
no of bar 12
Ast prov 1357.1680264 mm2
pt prov 0.1455564164 %
along short dir
pt req 0.1122288366 %
Ast req 1163.5885782
min Ast 1440
taken Ast 1440
no of bar 13
Ast prov 1470.2653619
pt prov 0.1418080017 %
spacing
along long span
c/c 180.72727273 mm
clear spacing 168.72727273 mm OK
along long span
c/c 190.66666667 mm
clear spacing 178.66666667 mm OK
oneway shear check
along longer span
length 0.456 m
P @ critical sec 135.68121693 kn/m2
Vu 209.78375 kn
Tau v 0.2249932969 N/mm2
Tau c 0.29 N/mm2 OK (put manually)
along shorter span
length 0.468 m
P @ critical sec 119.14210128 kn/m2
Vu 210.04285714 kn
Tau v 0.2025876323 N/mm2
Tau c 0.29 N/mm2 OK (put manually)
Two way shear check(at d/2 dist from face of column)
length 0.681 m
p @ this length 125.45056217 kn/m2
Vu 204.28351336
Tau v 0.6234390286 N/mm2
Tau c 1.25
ks 1
Tau c' 1.25
check(Tau v<Tau c')
Tau v < Tau c' OK
A Zx Zy P/A Mx/Zx My/Zy Pmax Pmin
5.04 2.016 1.764 101.851851852 54.56349206 28.344671202 184.76 18.94369
check
OK
