Effects of wall movements on performance of integral abutment bridges

Abutment walls in integral abutment bridges (IABs) move in a cyclic pattern in response to temperature-induced expansion and/or contraction of the bridge superstructure. The repetitive abutment movements cause an active-wedge slumping and passive-wedge densification of the retained backfill in the vicinity of the wall. These effects develop progressively with the number of abutment movements and eventually result in escalation of lateral soil pressure acting on the wall in addition to settlement in the approach adjacent to the wall. This paper investigated and gained further insight into the aforementioned effects on the performance of the integral abutments by means of numerical and experimental studies of an abutment wall retaining soil backfill and subjected to passive and active horizontal displacements. This paper also examined the application of expanded polystyrene (EPS) geofoam as a fill material to alleviate the lateral earth pressure ratcheting and the soil settlement in the IAB approaches.