Effect of Soil Spatial Variability on the Structural Reliability of a Statically Indeterminate Frame

Abstract

This paper presents a probabilistic procedure for assessing the structural responses of a statically indeterminate frame caused by soil spatial variability. Neglecting the soil spatial variability can underestimate the probability of structural failure, and lead to an unsafe structural design. The soil spatial variability is simulated by the random field theory implemented with Monte Carlo simulation. The diagrams of bending moment, shear force, and axial force induced by the differential settlement between the two footings of this indeterminate frame are solved by using the force method. The differential settlement, angular distortion, and frame internal forces are analyzed statistically. The probability of failure for three major structural failure modes, i.e., strength failure, in-plane buckling failure, and out-of-plane buckling failure, was rigorously assessed, revealing the dominant failure mode. It was demonstrated that there is a critical scale of fluctuation of soil property in the structural analysis. This study developed an innovative procedure for researchers and practitioners to assess the superstructure performance subjected to uncertain subsurface conditions.