Vertical load bearing behavior of bored pre-cast concrete piles

This paper presents behaviors of bored pre-cast Pre-stressed High-strength Concrete Piles due to vertical loads on reclaimed land in the southern part of Osaka, Japan. The same piles were used in two buildings whose locations are very close each other. The pile loading tests were conducted in two ways to compare the ultimate base resistance in different loading systems. The test results showed that the ultimate base resistance by pile tip loading was 1.7MN, which was at least 10% less than that by pile top loading. Strain measurements were carried out in working pile shafts during 15 months of construction in the site A. Accuracy of installed 1822 piles was surveyed in the site A. Statistics of the driven levels of piles and installation errors in position were obtained and discussed for limit state design of pile foundations.