System Reliability-Based Load Resistance Factor Design (LRFD) for External Seismic Stability of Reinforced Soil Walls

Abstract

In this paper, a system reliability-based load resistance factor design (LRFD) approach for the design of reinforced soil walls is presented to produce designs with consistent and uniform levels of risk for the whole range of design applications. First order reliability method (FORM) and series system approaches are used to determine appropriate ranges for the values of the load and resistance factors. Using pseudo-static limit equilibrium method, analyses are conducted to evaluate the external stability of reinforced soil walls subjected to earthquake loading. The potential failure mechanisms considered in the analysis are sliding failure, eccentricity failure of resultant force (or overturning failure), and bearing capacity failure. Partial factors needed to maintain the series system stability against three modes of failure by targeting a series system reliability index of 3.0 are obtained for six combinations of component reliability indices against sliding failure (βsli), eccentricity failure (βe), and bearing failure (βb). The load and resistance factors are proposed for a 6.0 m high wall for various values of coefficients of variation (COV) of friction angle of backfill and horizontal seismic acceleration coefficient.