Geosynthetic reinforcement stiffness characterization for MSE wall design

Abstract

Reinforcement stiffness is a key parameter that influences the magnitude of tensile loads in geosynthetic mechanically stabilized earth (MSE) walls under operational conditions. An estimate of reinforcement creep stiffness at 2% strain and 1000 h is required to carry out internal stability design using the Simplified Stiffness Method. This paper provides equations that can be used to estimate the reinforcement creep stiffness based on the tensile strength for different reinforcement product types. The paper also explores how the tensile strength values of a product can vary depending on the population of tests used to compute strength values. The differences in choice of nominal tensile strength based on lot-specific and minimum average roll value (MARV) are discussed. The paper demonstrates that the Simplified Stiffness Method soil failure limit state will usually control the selection of the reinforcement and not the tensile strength limit state. While the primary motivation for this study is to find creep stiffness values for the Simplified Stiffness Method, the stiffness-strength equations are useful in other applications such as numerical modelling of geosynthetic-reinforced structures where a reinforcement stiffness value corresponding to post-construction low tensile strain conditions is required.