Field Monitoring of Soil Response for Curved Integral Abutment Bridge during Seasonal Temperature Changes

Many integral abutment bridges (IABs) have been constructed due to their economic advantages as they lead to lower construction, maintenance, and repair costs during the bridge life cycle. However, the seasonal temperature-driven lateral movements may cause a complex behavior between the bridge structure and the soils behind and under the abutment, which could lead to undesirable results such as soil densification, void formation, and approach slab settlement. The response of the IAB to those movements is highly dependent on the overall structure, geometry, and location of the bridge. Furthermore, if an IAB is curved, it adds more complexity to its behavior. In this study, we attempt to investigate the behavior of a curved IAB via field monitoring continued through one seasonal cycle. It is observed that both abutments rotate and translate toward the backfill soil in summer because of the thermal expansion of the superstructure. This thermally induced movement increased the lateral pressure up to 75 kPa. The lateral soil pressure begins to drop as the temperature falls, but it does not return to its initial value while the abutments contract. It implies that irreversible deformation may occur during seasonal temperature changes. The obtained results also suggest that the foundation soil, the geometry, and curvature of the IAB, and the skew angle in the abutment could greatly influence the bridge’s behavior during seasonal temperature changes.