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. The authors discuss site conditions, pile installation and monitoring, instrumentation, grout mix design, load tests, grout strength and modulus tests, a procedure for converting strain to load, and residual loads and load transfer analysis. These residual loads were found to be relatively small, but not insignificant, and appear to have been related to site-specific soil profile characteristics. The residual loads were computed by using vibrating wire strain gauges to read strains along the piles at several times, both during and after casting, developing an approximation of time-dependent grout modulus, and computing stress and load increments from the incremental strains.

Language

  • English

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 223-235
  • Monograph Title: GeoSupport 2004. Drilled Shafts, Micropiling, Deep Mixing, Remedial Methods, and Specialty Foundation Systems

Subject/Index Terms

Filing Info

  • Accession Number: 01000177
  • Record Type: Publication
  • ISBN: 0784407134
  • Files: TRIS
  • Created Date: May 4 2005 7:26AM