Reliability Analysis of Long‑Span Concrete Box Arch Bridge under Temperature Effect Combinations

The existing design methods for concrete arch bridge structures do not consider the random characteristics of the eccentricity generated by load effects and overlook the influence of stochastic eccentricity on structural reliability. To address this deficiency, a calculation model for eccentricity under temperature effect combinations was derived. The random characteristics of eccentricity for different sections of the main arch of concrete arch bridges and their sectional bearing capacities were analyzed under different load parameter combinations. By utilizing the Monte Carlo method, reliability indices were computed for different sections of the main arch and different load parameter combinations after considering the random characteristics of eccentricity. The results indicate that considering the random characteristics of eccentricity leads to significant variability in the eccentricity of main arch sections, and the sectional bearing capacity may be governed by tensile strength. Reliability indices vary greatly with changes in the temperature-to-load effect ratio, suggesting that when the temperature-to-load effect ratio is significant, existing designs based on fixed eccentricity may lead to potentially unsafe designs.