Bearing capacity of pile preloaded by downdrag

Abstract

SYNOPSISAn instrumented steel-pipe pile, 49 m long, driven through a highway embankment into a deep deposit of compressible marine clay accumulated a peak downdrag load PN of 1.52 MN after 10 years. After the pile was filled with concrete, a comprehensive load-testing program was carried out over a period of 20 days to investigate the load-carrying capability of the pile. The locked-in downdrag load behaved as stored energy in the pile. Transient and short-term live loads up to PN and cyclic loads to stress levels of PN +33 1/3% were easily supported. Plunging failure occurred at an applied load of 2 PN.