Abstract
The cast in place concrete pile with outer steel pipe is a pile enhanced earthquake resistance by using a steel pipe at upper of the pile. We developed the new type of the pile. The flat steel pipe and concrete are anchored by shear cotters mounted at end of the pipe. The ultimate bending strength of this pile is evaluated by the general superposition method which is considered the influence of anchor strength by the shear cotters. The proposal design method was applied to this test of some specimens which have different anchor strength.