Elastoplastic Lateral Response Spectra of High‐Speed Railway Bridge with CRTS‐II Track System Considering Constraint Effects of Subgrade

High‐speed railway (HSR) bridges have remarkable dynamic amplification effects on the seismic responses of ancillary facilities located on bridges. To assist efficient seismic calculations of facilities on bridges, this paper develops lateral acceleration response spectra of HSR simply supported girder bridges with CRTS‐II track systems. First, this work creates a numerical model of the aforementioned HSR bridge‐track system considering the constraint effects of subgrade. The influence of peak ground acceleration and pier height on the response spectra of the bridge deck under elastic and elastoplastic states is investigated. Later, the generalized elastoplastic response spectra of the bridge with and without subgrade are statistically proposed. Then, a case study on the overhead contact line system validates the application and accuracy of the proposed lateral response spectra. Besides, the constraints effects of various track structures on lateral response spectra are quantified and compared. The results indicate that the constraint effects of subgrade amplify the seismic peak acceleration of bridge spans with increasing factors from near the subgrade to far. Elevating pier height will decrease the natural frequency of the bridge and increase the spectral long‐period components, while a rise in peak ground acceleration (PGA) will mainly increase the peak values of the lateral spectra. In addition, among the components in track structures, the base plate exhibits the highest constraint effects. The proposed generalized lateral response spectra are validated by the case study; therefore, it is advised to employ them for seismic response calculations and analyses of HSR bridges with subgrades efficiently and precisely.