Seismic damage of Daikai station and tunnel based on quasi-static pushover analysis

At present, the researches on the seismic damage of Daikai station and tunnel are mostly focused on dynamic time history analysis. However, they are characterized by a complicated modeling process and low calculation efficiency. The original Daikai station and tunnel as well as the newly built Daikai station are taken as examples. Firstly, the pseudo-static pushover analysis of the components is carried out considering the load and restraint conditions of the central columns under the seismic loads, and the seismic performance curves of the columns under different vertical compression loads are obtained. Secondly, the pseudo-static pushover analysis of the soil-structure system is performed by using the improved pushover analysis method, and the seismic damage of the Daikai station and tunnel is reproduced under horizontal and vertical earthquake loads. The analysis results show that the horizontal and longitudinal spans of Daikai station are larger than those of the tunnel. The axial compression ratio of the central columns significantly increaseds, especially after considering the earthquake loads. The ordinary reinforced concrete columns of Daikai station are prone to brittle failure caused by insufficient deformation capacity. The concrete-filled steel tube structure is applied in the central columns of newly built Daikai station. Under the same load conditions, the newly built central column shows better bearing capacity and ductility performance, which greatly improves the safety performance of the station structure.