Seismic Design of Deep Bridge Pier Foundations in Frozen Ground

AUTC project number: 107033

PI(s):

Sri Sritharan (ISU)

Funding:
  • US Department of Transportation (RITA)
  • Alaska Department of Transportation & Public Facilities
  • Start Date: Aug 3, 2007
  • End Date: Mar 31, 2011

Project Summary

This project developed design methods for drilled shaft foundations customized for Alaska's bridges, soils, and temperatures. Researchers tested how reinforcing steel, concrete, and soil behaved under cold conditions. They demonstrated cold-temperature effects on moment-curvature behavior of reinforced concrete and soil-foundation-structure interaction, established setup procedures for performing material tests at cold temperatures, discovered that temperature effects on stress-strain behavior of A706 steel reinforcement cause different behavior from that published in literature for similar reinforcement or structural steel, discovered the inadequacy of the existing method proposed for seismic design of drilled shafts (especially in cohesive soil), and developed more rational design methodology for drilled shafts in cohesive soil. The research team also prepared a review of state-of-the-art seismic design of drilled shafts. Its findings will be used to establish a new design methodology tailored to seismic regions subjected to seasonal freezing.