Back analysis of Tokyo port bay bridge pipe pile load tests using piezocone data

Schneider, J.A., White, D.J. and Kikuchi, Y. (2007) Back analysis of Tokyo port bay bridge pipe pile load tests using piezocone data. Kikuchi, Yoshiaki, Otani, Jun, Kimura, Makoto and Morikawa, Yoshiyuki (eds.) In Advances in Deep Foundations : International Workshop on Recent Advances of Deep Foundations (IWDPF07) 1–2 February 2007, Port and Airport Research Institute, Yokosuka, Japan. CRC Press. pp. 183-194 .

Abstract

This paper reports and back-analyses the results of two static load tests on 1.5m diameter instrumented pipe piles, conducted to aid the design of the Tokyo port bay bridge. The site investigation included high quality piezocone testing (CPTU), which is used to back-analyze the pile response in light of recently-developed design methods for axial pile capacity. Local shaft friction (τf) in sands, silts, and lightly overconsolidated clays, as well as unit base resistance (qb) of pipe piles in Tokyo gravel and Edogawa sand are evaluated using CPT qt. A simple expression for shaft resistance, which is an extension of the UWA approach for piles in sand, is shown to provide good predictions for the shaft resistance through the mixed sand, silt and clay layers at this site. The base resistance at a tip settlement of D/10 is a combination of resistance on the pile annulus and the enclosed soil plug. The unit annulus resistance is fully mobilized and comparable to CPT qt at the pile tip. The plug resistance is only 0.2qt,avg at the end of the load test, but steadily increasing, which highlights the conservatism in limiting pipe pile base capacity by a settlement criterion if the structure can tolerate additional movement.

This record has no associated files available for download.

Contributors

Author: D.J. White

Download statistics