Seismic performance of beam-type covered bridge considering the superstructure – substructure interaction and bearing mechanical property

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Modern covered bridges have attracted attention due to their multifaceted commercial functionalities, making them increasingly prevalent in construction projects throughout China. To investigate the seismic performance of the beam-type covered bridge, finite element models (FEMs) of conventional building structure, conventional bridge structure and covered bridge structure were established via OpenSEES. The effects of bearing mechanical properties on the seismic response of the whole covered bridge and impacts of lower bridge structure on the interlayer drift ratio of upper building, as well as influences of upper building structure on bearing displacement and pier displacement and stress were deeply explored by using (Incremental dynamic analysis) IDA method. Furthermore, the seismic performance of the covered bridge was evaluated under two levels of seismic hazards. Results indicate that under the seismic events may occur, the interaction between superstructure and substructure is adverse to the longitudinal seismic performance of the superstructure and wall pier of the covered bridge, but do not significantly impact the lateral seismic response of the superstructure. The existence of the superstructure notably reduces the displacement of bearings. Moreover, higher bearing stiffness lead to a more pronounced interlayer drift ratio within the superstructure of the covered bridge. The influence of bearings on the displacement and stress of wall piers is not affected by the superstructure- substructure interaction. This study involved the nonlinearity of the structure and the randomness of seismic actions and clarified the impacts of factors on the seismic response of the beam-type covered bridge. Finally, a reasonable layout of the bearings was proposed.