Piles and Foundation: Vincent Chu Answers
How do rock sockets take up loads?
The load transfer mechanism is summarized as follows:
When a socketed foundation is loaded, the resistance is provided by both rock socket wall and the socket base and the load distribution is a function of relative stiffness of foundation concrete and rock mass, socket geometry, socket roughness and strength.
At displacements beyond 10-15 mm, relative displacement occurs between rock and foundation and the socket bond begins to fail. This results in reduction of loads in rock-socket interface and more loads are transferred to the socket end.
At further displacements, the interface strength drops to a residual value with total rupture of bond and more loads are then distributed to the socket end.