Residual Load Development in ACIP Piles in a Bridge Foundation

It has traditionally been assumed that when cast-in-situ piles, such as drilled shafts or ACIP piles, are constructed, the residual stresses after curing are zero. When conducting load tests on instrumented cast-in-situ piles, therefore, the readings in the strain gauges at the beginning of the load test are assumed to represent an unstressed condition. The implementation of ACIP piles in a bridge foundation in the Texas DOT system recently has allowed for the measurement of residual loads in several ACIP piles during curing. These loads were found to be relatively small, but not insignificant, and appear to have been related to site-specific soil profile characteristics.