Question

A 400 mm x 400 mm column supports a DL = 500 KN, LL = 1000 KN, MDL = 600 KN-m, and MLL = 600 KN-m. It is required that the column must be placed at the center of the square footing. Assume that the weight of the footing and the soil above is to be 15% of the total service load. The soil bearing capacity is 209 KPa, fc’ = 27.6 MPa, and fy = 414 MPa. Design completely the square footing. Provide the footing plan and elevation. Use ACI Method

Answer 1

Given column size = 400mm x 400mm ~ 1611 X 1611 DL=500KN 7 113k LL = 1000 KN ~ 225k MDL=600kn-m= 442 kaft MLL = 600 KN-m = 442 k-ft fcl = 27.6MPa = 4ksi = 400opsi fy = 414 Mpa boksi =60000 psi qa = 209 kp a = 4365 psf BY ACI Method We know that Total load = 1.2DL tlo6LL =(1-2x113 +1.6x225) - 495.6 = 496 kip Área of footing = Total load qa (496X103 4365 = 113.63ft2 size of footing = J113.63 = 10:65 feet ~ Iffect Provide size of tooting = lift x114 Actual area provided = C11Xll) = 121472

We know that Bearing pressure for strength aesign ( Total loa Алеа -14 (498 121 = 4.13 ksf ☆ calculation of depth required and two way Punching shear & Assume depth (a) = 24112257 T From figure, we get 16 lift bo=4 (16"+24,"+24') - 4 (40) 161 Aak bo = 160" K 11ft = 13.33 ft Also Vuz = (121ft? - 13:13 feet) x 4.13 = 441.37K d = Vuz 441.37x103 0.75 Xux J X160 4000 0875xy Sfcl Xbo =14:53! L2411 Hence ok

117 calculation of depth required for one Way shear - (2.83+2) = 4.83' We know that Vu=1'(2-82X4-1385 = 128.56 ksi bo = (1/12)=132" 1611 111 1611 111 d = Vui 0.75 X2 5f0! X132 (11 8-21 T2 2') = 2.83 128-58X103 0075X254000 X132 C. 10.26 in <24 in Hence ok We know that Mu= (4.83 feet )* (11 feet ) x4.13 X 4.83 2 529.gik-ft Mu obd2 12 in /feet ( 529910 feet-ebo 0.9 X 132 X(24)2 =92.92 psi =0.00225 <8 min for flexure use 8= larger of 200 = 0.0033 8 60000)

or 35 400 opsi -0.00316 60oOopsi As = 6.0033)x13 132 inch xzuinch = 10.45 in 2 over the entire 132 inch wiath use 11 bars of #g in both direction (As = 11 in?) "I feet #gin4 both direction 11 feet Figo Footing plan d=24" *ll bars of #9 in both direction. figure - Footing elevation