Fuzzy-stochastic stability analysis of soil-steel structures under uncertainty

Evaluating the safety of geotechnical structures affected by the uncertainties in design parameters is of crucial importance. In this regard, assessment of the response of soil-steel structures under uncertainty is essential, however, this has not yet been studied. In this study, a fuzzy logic-based model is employed for analyzing the effects of uncertainty on the performance of arch soil-steel structures. The input uncertainty is introduced into the equations governing the design. Then, an optimization problem is created for finding the possible maximum and minimum values of the factors of safety for different levels of risk. To this end, the influence of uncertainty on the stability of three example structures of arch, high profile arch, and low profile arch designed based on the Canadian Highway Bridge Design Code (CHBDC) approach, is investigated. The results indicate that a slight input uncertainty can seriously violate the safety of the structures. For instance, ± 5% uncertainty in the input parameters leads to the total variations of 262.01%, 220.15%, and 245.48% in the factors of safety of example arch, high profile arch, and low profile arch structures, respectively. In addition, the sensitivity of different factors of safety to the uncertainty of each input variable is compared through a sensitivity analysis for the three types of arch structures.