Reliability-Based Internal Stability Design for MSE Wall Structures

This paper demonstrates the general approach for reliability-based internal stability design of mechanically stabilized earth (MSE) wall structures using as examples the limit states associated with internal stability of steel strip, steel grid, geogrid and PET strap MSE walls. An important feature of the general approach is a quantitative link to the deterministic factors of safety used in past practice. The calculation of reliability index (or equivalently the probability that the internal limit state is not satisfied) includes the contribution of model method bias and the uncertainty in the estimate of the nominal load and resistance terms in each limit state performance function. The estimate of reliability index can be carried out using Monte Carlo simulation or using a closed-form solution for the case that bias and nominal values are lognormally distributed. The general approach includes the quantitative influence of (model) bias dependencies with nominal values and possible correlations between load and resistance nominal values that are possible when analytical equations for load-side and resistance-side contributions have common input parameters, which themselves have some uncertainty.

Keywords: Mechanically Stabilized Earth (MSE) walls, Reliability-based design, Internal stability.