Reliability-Based Load and Resistance Factors for Soil Nail Walls Against Facing Failures

The paper pertains to a load and resistance factor design (LRFD) based reliability assessment of soil nail walls against facing failures. Three facing failure modes, i.e., flexural, punching shear, and headed-stud tensile limit states, have been analyzed. Both default and improved Federal Highway Administration (FHWA) load models and only the default FHWA resistance model have been considered to formulate the limit states against facing failures. Variation of design parameters associated with each limit state over the depth of the wall has been examined for different target reliability indices and levels of variability of the random input variables. The load and resistance factors corresponding to each input variable have been estimated for different target reliability indices. The effect of the variation of each random variable on the load and resistance factors has also been assessed. Results reveal that the maximum required design parameters to achieve the prescribed target reliability index can be minimized by adopting the improved FHWA load model. It also emphasizes that the variability of the input variables imparts a significant influence on the load and resistance factors. The effect of the correlation coefficient between soil parameters on the load and resistance factors has also been highlighted in this study. Finally, the efficacy of the present approach has been shown through a design example.