Question

Problem 5-Bearing Capacity of Shallow Foundation (20 pts) For a square footing foundation, the following are given: B 3.0 m (width), D 1.2 m (depth). Y=20 kN/m3, = 32°, c' = 50 kPa, Use Terzaghi Equation and a factor of safety of 2.5 to determine the allowable bearing capacity and the maximum column load to cause bearing capacity failure. Assume that general shear failure occurs in soil. When Oar C S

Answer 1

Step 1 : Given Dala, Type of foundation = aquare wichth = B = 3.0m Depth =D = 1.2m n 20 kN/m 3 0' - 32° c'a sokra FOS: 2.5 stepal :- Terzaghi's Becuring capacily factors for General Shecer failure 18, For friction angle = $'? 32° Ne = 44,04 No = 28.52 Nr = 26.87 u Himate beooring capacity of soil for speare footing au = 1.3 CNC + V.Dr. Nq +0.4.7. B. Ng 2(1.3 x 50 x44.04 ) +(20x1.2 x 28.52) +6.4 x 20x 3 x26187) - 2862.6 + 68 4.41 8 + 644.88 = 4 191.96 kN/m2 nel ultimale bearing capacity of soil anu = qu-r.D 4191.96-(20x1.2) = $167.96 Pallow cor) Ons - Inu = 4167.96 2.5 KN/m2 qs anstr.o - 1667.184+ (20x1.2) - 1691. 184 kN/m². FOS 1667.184

foot Maximum Column load (or) as Area of square dafe load = Q = ! 1619 Q= 1691,184* (3) 2 = 15220.656 IN. AQ. 15220.656 km ] allowable load a Call * B2 - 1667.184 x 302 = 15004.656 KN - Qallow = 15006.656 KN