In: Civil Engineering
Design a square concrete column footing to support a 500-mm x
500-mm reinforced concrete column. The center of the column and
footing must coincide.
Loads: ???=350 ??, ???=480 ??, ???=100 ??−?, ???=130 ??−?
Column Design Criteria: ??′=28 ???, ??=400???
Footing Design Criteria: ??′=28 ???, ??=400???, ??=175 ???,??=1.50
?, ??=16 ??/?3,??=24 ??/?3, ??=20 ??, assume a thickness of the
footing of 500 mm.
load PDL = 350KN
PLL = 480KN
SBC = 16 X 10=160 KN/m3
load combination = 1..5( 350 + 480) =1245 KN
area of footing = load on footing /SBC =1245/16 =7.781 m2
size of footing =3 x 3 m
rea provided = 3 x 3 = 9 m2
net upword pressure
critical section of the footing
critical section of footiing@ face of column from the edge of footing
3000/2 - 500/2 =1250mm
bending moment
net moment = MDL + MLL = (100 + 130_) x 1.5 = 345 KNm
provided total depth as 1.5 m
reinforcement
=0.0153%
=674.73 mm2
no of bar =
CLEAR SPACING =(3000-50-50-10-10)/ No of bar - 1 =1440mm
more so not ok
reduce bar size 12 mm
CLEAR SPACING =(3000-50-50-10-10)/ No of bar - 1 =550 mm
one way shear
Vu - up ward pressure x area of critical section = 207.5 x 3 x 0.6 =372.6KN
safe for shear