Performance and damage states assessment of thin-walled steel bridge piers with end-corrosion under earthquake loading

Abstract

End-corrosion is typical damage to steel bridge piers, which will reduce the seismic performance. Unlike overall uniform corrosion, end-corrosion results in more complex stresses on bridge piers, however, there are few related studies. This study aims to analyze the mechanical performance of corroded bridge piers and to establish a method for evaluating the seismic damage status of steel piers considering circumferential uniform end-corrosion. Firstly, the effect of corrosion parameters on key performance points of bridge piers is quantitatively analyzed using the validated finite element model. The calculation method of critical displacement value corresponding to different damage states of the end-corroded bridge pier is proposed. A high-precision fiber beam element analysis model is developed to simultaneously consider the effects of end-corrosion and shear stiffness variation. The results show that the degradation degree of yield displacement of the end-corroded bridge pier is relatively small. In contrast, the ultimate displacement, capacity point displacement and bearing capacity are significantly affected by corrosion parameters, and the degradation degree after corrosion can reach more than 30%. The pier damage ratio formula proposed in this study can accurately describe the degradation of the ultimate value, and the calculation error is almost controlled within 15%. The multi-node variable section (MNVS) fiber beam model proposed in this study has higher analysis accuracy, which can be improved by more than 16% compared with the traditional fiber beam model. In addition, the accuracy of the MNVS model in the dynamic analysis is verified by inputting the seismic records under three site conditions. Finally, considering the characteristics of end-corrosion, an evaluation method and procedure for seismic damage status of the steel pier with end-corrosion is established.