Question

In the figure shown a square footing 3m x 3m has a thickness, h= 600mm and effective depth, d= 530mm. The concrete compressive strength, f = 28MPa and the reinforcing steel yield strength, f = 420MPa. The footing carries a rectangular column of 40 cm x 60 cm. Check the adequacy of the footing to carry an axial dead load of 1200 kN and an axial live load of 1600 kN based on shear strength requirements. 3 m 60 cm 3 m 40 cm

Answer 1

Complete solution is given below.

17 Check for S-way sheasa Shear colitical section is at distance of from colour y Shear perimeters a (Goo+d) + 2 (400+d) = 2(600 +530) + 2(400 +530) bo 4120 muy * Pn= 1.2 DL + 1.6LL (1.2x1200) + (1-6x1600) = 4000 kn) XP qu= BAL * Factored det soil pressure Pu 4000 3x3 Appelp offly KN/m wwt) Total shear force for a very shear Vuza Phan qu (erd) (bxd) qu

V uz = 4000 4000 - 444.44 (0.6 +0.53) (0.4+0.13) Vu2 = 3532.94 KN 600 * Two way shear capacity, o Vn Ø Vm = 0.17 it e ] Je bed B = Longer side of colvarn = 1.5 ADD Shorter side of column .. 4 V = 6.7 (1+ 28 x 4120 X 530 X 0.75 dYu = 3437.47 KN X Vuz 2 1.5 ... Two way shear > Shear capacity Ustsafe under &-way shear

27 Check for 1-way shear * projection i - (a + b) B 2 = 3000 2 (530 + 4.00 2 re' = 770 mm мм } * Total Shear force on Colitical section cd' from colume Vui = B x2 xqu = 3*0,77 x 24494.44 K Venus = 1026.66 kw) * One way shear capacity, dxn d In = 6x0.14 alte x B xd =0.75*0.1 x 128 x 3000 x 530 Kevin - 1072. 72.)KW > Vue . Shear capacity is greater than applied man shear "Safe under 1 - way shear