Optimal IMs for Seismic Demand Modeling of Girder Bridges Subjected to Pulse-Like Ground Motions

Recent efforts of fragility analysis of structures often pose a challenge in selecting optimal intensity measures (IMs) for ground motions. This paper proposes a general procedure for determining optimal IMs based on feature selection. Firstly, the statistical models, such as forward stepwise regression, principal component analysis and generalized linear regression, are presented in detail. Secondly, a total of 29 ground motion IMs are considered in the current research, and 139 ground motions with velocity pulses are selected from Pacific Earthquake Engineering Research Center database. Thirdly, the optimal IMs for the general regular girder bridges subjected to the selected ground motions are determined by feature selection. Finally, a case study is conducted to validate the effectiveness of the proposed method for optimal IMs selection. The numerical results reveal that the optimal IMs for regular girder bridges subjected to ground motions with velocity pulses are peak ground velocity (PGV), velocity spectrum intensity (VSI) and compound vel.-related IM ( ). In addition, the first principal component of the selected IMs can contain the most of the information, thus only the first principal component is enough to establish the PSDMs of the bridge components. The proposed general procedure for optimal IMs selection is applicable to other structures.