A Numerical Study on the Abutment-Backfill System Subjected to Lateral Loading

The abutment-backfill system plays an important role in transferring laterally generated forces from the bridge deck to the foundations on either end of the bridge. The soil used as the backfill material dictates the behaviour of the abutment-backfill system by mobilizing the forces in the form of stress. In a seat-type abutment, the in-plane lateral resistance is provided both by backfill and underneath piles, but the out-of-plane movement is mainly restricted by piles. It is necessary to study the behaviour of the abutment-backfill system under lateral loading. In the present study, a continuum 2D abutment-backfill-pile model is developed in OpenSees conforming to the site conditions of the Rohtak Railway Bridge project. Initially, a monotonic and cyclic pushover analysis is carried out to estimate the monotonic and cyclic capacity in terms of load–displacement curves. Two types of lateral loading conditions are chosen such as monotonic loading and sinusoidal loading. The global level behaviour at the critical positions is estimated to get an insight into the response characteristics of the system.