RELIABILITY ANALYSIS OF RC STRUCTURES CONSIDERING SOIL STIFFNESS VARIABILITY AND SOIL-STRUCTURE INTERACTION

Abstract

This study investigates the reliability of reinforced concrete (RC) structures under variability in soil parameters, modeled using random fields. Numerical simulations with OPTUM G2 software and Monte Carlo methods evaluate the effects of spatial soil stiffness variability on internal forces, deformations, and settlement patterns, emphasizing soil-structure interaction (SSI). Key results indicate that even small differential settlements induced by SSI effects can generate bending moments and shear forces that impact structural stability. Random fields of Young’s modulus, modeled with a mean of 10 MPa and a coefficient of variation (COV) of 30%, reveal significant spatial variability. Stiffer soil zones exhibit reduced settlement, whereas softer areas undergo greater deformation, affecting load redistribution. Failure probability (P_f) analysis highlights high sensitivity to correlation distances, peaking at 12.5% for intermediate distances (4–12 m) and diminishing at shorter or longer values. These findings underscore the importance of considering SSI and soil heterogeneity in structural design to avoid underestimating deformation and stress responses. By integrating realistic variability in soil properties, this research offers insights into optimizing RC structure reliability under geotechnical uncertainties.