Longitudinal Behavior of Concrete Pipes with Combined Defects of Corrosion, Crack, and Void under Traffic Loads

The coexistence of defects such as internal corrosion, cracks, and surrounding voids is frequently observed in concrete pipes. However, the mechanical response of concrete pipes subjected to the combined influence of these defects remains insufficiently understood. This study develops three-dimensional simulation models of pipe–soil systems, incorporating internal corrosion, longitudinal crack, and surrounding void, both individually and in combination. The investigation evaluates the effects of individual defects as well as their combined impact on the longitudinal behavior of concrete pipes. Numerical results for the combined defects are validated through comparisons with experimental data. The results indicate that corrosion, crack, void, and combined defects increase the peak stress at the crown by 31%, 10%, 33%, and 37%, respectively, and at the invert by 11%, 22%, 33%, and 56%, respectively, compared to intact pipes. Moreover, combined defects further elevate the peak stress at the crown by 5%, 25%, and 3% and at the invert by 36%, 28%, and 18%, relative to pipes with corrosion, crack, and void defects, respectively.