Vertical Settlement of Strip Footings on Top of Geosynthetic-Reinforced Retaining Abutment Walls

Geosynthetic-reinforced retaining (GRR) walls have been widely used in the construction of bridge abutments and approach slabs. Traditionally, deep foundations carry the bridge loads, rather than the abutment walls. Bridge loads can be supported directly on footings constructed on the reinforced soil mass. Settlement of footings on top of GRR abutment walls is a key parameter that should be considered for design of these structures. The objective of this study was to develop a method to estimate the vertical settlement of strip footings on top of GRR abutment walls. To achieve the above objective, the effect of strip footing loading on stability of several GRR abutment walls with flexible facing was investigated. Limit equilibrium analyses were conducted to determine the factors of safety of these abutments. The calculated and measured settlement results indicate that the GRR abutment walls with lower factors of safety had larger vertical settlement of footings than those with higher factors of safety. Based on this finding, a data analysis was conducted to establish an exponential relationship between the calculated factor of safety and the maximum vertical settlement of footings on top of GRR abutment walls.