Bridge Approach Settlement and its Mitigation Schemes: A Review

Abstract

The primary function of the bridge approach is to provide a seamless transition from the highway or railway embankment to the bridge structure. However, a sudden change in elevation (drop/bump) at the transit of these two has often been observed. This sudden drop/bump acts as a potential cause for motorist discomfort, impact on the bridge deck, and cracks on the pavement surface. This phenomenon of ground settlement or deformation that can occur near the approach or abutment of a bridge for various reasons is often referred to as bridge approach settlement (BAS). Several researchers have contributed to formulating the reasons behind BAS and have proposed several mitigation techniques. This manuscript provides a comprehensive literature review on the causes of BAS, the contribution of various research works on mitigation techniques, and experimental, numerical, and field studies of various BAS mitigation schemes. The causes and mitigation techniques are categorized based on major components of the bridge structure, that is, the foundation, abutment, backfill soil, bridge approach, and bridge deck interface. Each of these mitigation schemes has advantages and disadvantages, and the best approach will depend on several factors, such as the type of soil, the loading conditions, and the design of the bridge and its approaches. The feasibility of various mitigation schemes is also reviewed with respect to their efficacy and ease of use.