Evaluation of reinforcement layout on the serviceability of MSE walls supporting footings

Abstract

Mechanically stabilised earth (MSE) walls are becoming an increasingly common means of supporting footings, particularly those that support bridge superstructures. A verified numerical model employing finite-element (FE) analysis was used to investigate the influence of non-uniform reinforcement spacing on the performance of footing surcharged MSE walls. The effects of reinforcement density were evaluated under two scenarios: a ‘top-down’ approach where reinforcement spacing density is progressively increased from the top of the wall downwards and a ‘bottom-up’ approach where the spacing density is progressively increased from the toe of the wall upwards. Lateral deformation of the wall face, footing settlement and reinforcement strain were evaluated for varying conditions. Moreover, the development of shear mechanisms within the reinforced soil was evaluated. For MSE walls supporting footings, placement of closely spaced reinforcements in the upper portion of the wall was found to be more beneficial. Alternatively, when MSE walls do not support any surcharge, placing dense reinforcement near the toe is the most beneficial. Tailoring reinforcement spacing to MSE wall function can result in economic benefits by reducing the required bridge deck length or reducing the required reinforcement quantities. This study quantified the impacts of reinforcement configuration on service-state behaviour.