Influence of frozen soil on the seismic responses of bridge structures considering the effect of temperature

Abstract

Objective Recently, the seismic damage of an actual bridge structure in a frozen soil area has shown that the presence of frozen soil will increase the lateral stiffness of the bridge foundation, which may cause more serious seismic damage to the bridge structure, but there is a lack of research on the frozen soil-pile interaction effect of frozen soil bridge structures under seismic loadings and the corresponding seismic responses. Methods The present paper proposed efficient nonlinear numerical models to consider the effect of the frozen soil-pile interaction on the seismic responses of structures. First, the relationship between the depth of frozen soil and surface temperature was constructed. Then, the p-y spring modelling approach was presented to simulate the seismic behavior of frozen soil. Several as-recorded ground motions were selected as the seismic input. The seismic responses of piers and bearings of regular bridges with different depths of frozen soil under seismic loadings were investigated. Results The results show that the proposed efficient nonlinear numerical model can be adopted to model the seismic behavior of bridges considering frozen soil. And the proposed p-y curves for frozen soil can accurately predict the p-y relationship from the existing tests. When the PGA is relatively small, the pier curvature increases slightly; by contrast, in the case of large PGA, frozen soil can significantly increase the curvature demands, which can make the pier enter into the inelastic behavior. When the depth of frozen soil is small (the temperature is -5℃), the bearing displacement increases significantly, which increases the probability of unseating under seismic loadings. Moreover, frozen soil can transfer to the adverse locations of structural systems under seismic loadings. Conclusion Therefore, the conclusions of this paper can provide the necessary theoretical basis and data support for studying the seismic performance and corresponding seismic design methods of frozen soil bridge structures in China, which is of great significance for promoting the development and engineering application of disaster prevention and mitigation of bridge engineering in frozen soil areas in China.

Keywords

• seasonal frozen soil
• bridge structure
• numerical simulation
• seismic responses
• temperature effect