Rapid determination method of the seismic failure modes of coastal bridge columns in the whole life cycle

Abstract

Due to the different corrosive conditions in the atmospheric zone, splash and tidal zone, and submerged zone, coastal bridge columns in marine environment always suffer from non-uniform corrosion along the height. As a result, an important phenomenon of plastic hinge transfer can occur, which has a significant effect on the seismic performance of the coastal structures. However, this problem has seldom been studied. The plastic hinge transfer phenomenon has been observed in previous cyclic loading and shaking table tests of the authors [1,2]. In this study, a further study focusing on the changing time of different failure modes and the plastic hinge length is conducted. First, the possible failure modes resulted from the non-uniform corrosion are discussed, in terms of the distribution of plasticity at the ultimate state. Then, a finite element modeling method of the bridge columns with different service time is developed. Equations that can predict the failure mode are proposed based on multi-parameter regression analysis. Finally, a flowchart describing the rapid determination method of the time-dependent failure mode and the way to obtain the equivalent plastic hinge length is proposed. The results indicate that the prediction method is with high accuracy and efficiency, which is helpful for the seismic performance design and evaluation of the coastal bridges during the entire service life.