Question

reinforced concrete design , ACI code

Q4 Design of isolated footings A 500 mm x 250 mm reinforced concrete column carries unfactored dead load of 1400 kN and unfactored dead load of 600 kN. The column is supported by a rectangular footing located 2.00 meters below ground level where the allowable soil bearing capacity is 292.4 KPa and unit weight is 20 kN/m2. Concrete compressive strength is 35 MPa and reinforcing steel yield strength is 420 MPa. 1. Calculate the required dimensions of a 600 mm deep rectangular footing to prevent excessive settlement under the column such that the ratio of the long side to short side of the footing is 2:1. 2. Determine whether the footing dimensions determined in (1) above are safe against two- way shear failure assuming No.16 reinforcing bars. Assume the supported column is that the long side (500 mm side) is parallel to the short side of the oriented so supporting footing. 3. Determine the required number of No. 16 reinforcing bars placed parallel to the long direction of the footing and validate the appropriateness of the spacing. Assume the supported column is oriented so that the long side (500 mm side) is parallel to the long side of the supporting footing. 4. Calculate the development length of No. 16 zinc-coated (galvanized) bars in the longitudinal direction and indicate whether the available footing dimension is appropriate.

Answer 1

Given Column S0Drn m DL 400 KN 600KN LL : 2 m Deph offoundatiun D 29 2 KPa Safe Beaing Capauty SIC 20 km unit weigh of soi) 35 MPa amerete Cumpreccive srenh fe strengh f Yietd Sauice load 2000KN uoo+600 Fadored oad, SX206D 2000 kN Given thckness of ootirg, D 60omm soil e'ght Load x 2 Area of feotvg, A Pu -23o00kN A SBC 292.4 toも 12:312m2 Givem L= 2R にて A LB マM21Eて1 CS Scanned w B CamScanner B 2.6 m 12.312

L n2x26 72m Dimensims of retangulan fostirg is 460omm x 2300mm. T 3600 SoO cs Scaedrith: Cantsaer J200

Given #16 steel baru ane prauided neinfercement Load Prescue o soil Arca 12x2000 PO 3-6x72 23 38.89k fostirg Yeinforce ment be Ld the COve sed 20 bars Somm Ond One d D-Cove - - 6oo-SO- 2 S40mm Two way shean is 25D along clitame from faie of 4 600 columm 790mm abd (Ohom SOD CS CamScanner

Shean, N A 7pox 2.600 - 70 b8 & 3486 KN Nominal shean trecs 4h'bd 3486 XID 4 oo+7) For sefety Shortsidle column SOO Long side of column Ke=ロ-5ャOS =1 Ks Te CS Sanfeh in two woy shoa CamScanner