A raft foundation subjects its supporting soil to a uniform pressure of 300 kPa. The dimensions of the raft are 6.1m by 15.25m. Determine the vertical stress due to the raft at a depth of 4.58m below it at the central points of the long edges.
Influence factors for the vertical stress beneath the corner of a rectangular foundation (after
i) at the center of the raft
z= 4.58 m
n= = 1.67 obtained from the graph.
ii) at the central point of long edges.