Simplified seismic model of CRTS Ⅱ ballastless track structure on high-speed railway bridges in China

摘要

An effective simplified model of CRTS II ballastless track structure is proposed in this paper and is expected to applied into the practical seismic design and analysis of high-speed railway (HSR) bridges in China. The bridge model (BM), as recommended in Chinese seismic design code, simplifies modelling procedures to cater for practical designs and constructions without considering the constraint of track structure on the bridges. Although the BM possesses great computational efficiency, it may produce unreasonable results as compared with the bridge-track system model (BTM) that incorporates the influence of track structure. Nevertheless, the BTM is actually not an effective practical-orientated alternative applied into the seismic design and analysis of HSR bridges due to the demand of massive computation. Therefore, this paper concentrates on the improvement of HSR bridge models applied into the practical seismic design and analysis. A simplified seismic model of China Railway Track Structure II (CRTS II) ballastless track structure on China's HSR bridges is proposed. The proposed simplified track model is computationally effective and significantly improves the calculation accuracy of the code-recommended BM as it can accurately simulate the longitudinal constraint influence of track structure on bridges. Additionally, the proposed simplified track model can be applied into capturing evaluating performance stateof track structure and judgingearthquake-induced collision of adjacent girders. By comparing seismic responses of the BM, BTM and the bridge-simplified track model (BSTM), results validate that the simplified track model possess computational effectiveness and calculation accuracy.