Vessel collisions pose significant threats on the safety of cross-channel bridges. Previous studies have paid little attention on the impact performance of common arch bridges with gravity foundations in inland waterways. This study aims to comprehensively investigate the anti-impact resistance and analyze the damage and failure mechanisms of arch bridges under vessel collisions. The entire process of vessel-bridge collision is simulated using three-dimensional explicit finite element technique. The damage characteristics, as well as the progressive collapse process of arch bridge are investigated thoroughly. Moreover, the rational calculation method for bridge lateral resistance against vessel collisions (BRaVC) is discussed. The results show that the gravity foundation bottom of arch bridge can be fixed in vessel-bridge collision numerical analysis due to insignificant foundation-soil interaction. The head-on barge collision on the bridge pier leads to indistinctive lateral displacement, while obvious local damage can be observed. The impact displacement of the bridge pier is not positively correlated with the impact energy according to the impact load spectra analysis. Barge collision on the main arch results in the progressive collapse of the bridge due to unbalanced horizontal thrust from the arch on the other side. The rational BRaVC can be calculated by using sectional strength based on elastoplastic analysis.

Progressive collapses of tied-back excavations caused by the failure of some anchors often occur. However, the mechanism through which partial failure evolves to global failure and how the local failure rate influences progressive collapse has not been investigated. In this study, anchor failure experiments involving tied-back excavation were designed to explore the load transfer path and rule in the case of partial anchor failure. The results showed that, anchor failure leads to an increase in the axial force on adjacent anchors, an increase in the maximum bending moment of capping beams, and easy damage in capping beams due to structural reinforcement. The lower the anchor elevation is, the greater the excavation depth, and the greater the load transfer coefficient (axial force). The failure rate of anchors has an effect on the stress redistribution of the structure and the soil arching effect. In multi-row anchored pile retaining excavations, more rows of anchor failure could trigger the remaining anchors failure because the load transfer coefficient (axial force) is greater for these anchors, which leads to large-scale excavation collapse.