Experimental Study on Seismic Failure Mechanism of Elevated Pile-cap Foundation for Bridge Structures

Abstract:

This paper focuses on the seismic failure mechanism of elevated pile-cap foundation in bridges. Pseudo-static testing were carried out on two 2×3 elevated reinforced concrete pile-cap foundation specimens in sand. Numerical pushover analysis based on Beam on Nonlinear Winkler Foundation (BNWF) model was conducted. Results indicate that side piles yielded earlier than middle piles. Each pile forms two plastic hinges at pile-top sections and under-ground pile sections with the depth of approximately 3~8 times of section width respectively, specimens suffer failure damage when the top section of the side pile attain to the theoretical ultimate curvature. The pile-top damage area is not sensitive to the above-ground height while the under-ground pile damage area is sensitive to the above-ground height.