Analysis of the maximum reinforcement loads of four MSE walls compared to the values predicted by the AASHTO 2020 specification

Abstract

Mechanically stabilized earth (MSE) systems are a well-known and applicable solution for retaining walls, that presents a composite structure consisting of layers of backfill soil with rigid or flexible reinforcement inclusions. The stability of the wall system is derived from the interaction between the backfill and soil reinforcements involving friction and tension. The wall facing has as its main function to prevent erosion of the structural backfill. The design of MSE walls is usually divided in two phases: external and internal stability. Although there are many methods to design MSE walls, the Coherent Gravity Method is the most common used for MSE walls reinforced with inextensible (steel) reinforcements, the Simplified Method for both steel and geosynthetics reinforced wall systems and the new one included in 2020, Stiffness Method, to calculate the maximum reinforcement loads, Tmax, for extensible (geosynthetics) reinforced MSE walls (all these methods are outlined in Section 11 of the AASHTO LRFD Bridge Design Specifications 2020) . The main objective of this paper is to carry out the analysis of the 3 methods available at AASHTO and compare the results from full-scale MSE walls and the predicted Tmax values.