STIFFNESSES OF ABUTMENTS ON SPREAD FOOTINGS WITH COHESIONLESS BACKFILL

Characterization of bridge-abutment-backfill interaction is an importa nt component in seismic bridge response evaluations. The paper present s a relatively simple and realistic methodology to evaluate the nonlin ear translational (longitudinal, vertical, and transverse) spring stif fnesses to represent bridge-abutment-backill interaction. Many importa nt factors such as the nonlinear soil behavior, abutment dimensions, s uperstructure loads, and difference in soil behavior under active and passive conditions have been accounted for. Only routinely used soil p roperties are required in the model. The results predicted by the prop osed approach have been calibrated against abutment stiffnesses (longi tudinal and translational) measured in large-scale field tests. The ag reement between the predicted and measured stiffnesses is very good. S ubsequently, the approach has been used to develop normalized relation ships for abutment stiffnesses.