Seismic Fragility Analysis Of Small And Middle Size Railway Passenger Station Buildings Based On IDA Method

Seismic fragility analysis, which could quantificationally describe seismic performance of structures in the sense of probability and broadly depict the relationships between different earthquake intensities and structural damage levels, refers to the failure probabilities of structural members’ or systems’ different performance levels under different earthquake intensities. It attracts more and more attention in academic field. Based on incremental dynamic analysis, performance, seismic fragility and collapse performance analysis for small and middle size railway passenger station buildings are carried out using numerical analysis in the paper. The main work are as follows:(1) The paper introduces and summarizes basic information of railway passenger stations and focuses on that of small and middle size railway passenger station, which includes common structural types, structural systems, features, functions, seismic fortification lines and so forth. After comprehensive consideration, three typical small and middle size railway passenger stations are selected for analysis.(2) Based on finite element software ABAQUS, the paper does numerical analysis of the three selected railway passenger stations. Several strong earthquake records are selected as ground motion input and top drift is chosen as damage measure. Incremental dynamic analysis is carried out using PGA and Sa(Tl,S%) as earthquake intensity separately with input of horizontal seismic waves along weak axis of structures. Four performance levels are proposed for small and middle size railway passenger stations. Damage index values of different performance levels are chosen based on50%IDA curves according to the relationship between structural stiffness and slopes of IDA curves. Damage description of different performance levels is carried out based on numerical analysis and earthquake survey. Failure mechanism and weak parts of these stations are summarized according to the development and distribution of plastic hinges of structural models during earthquake. Influence of staircase on seismic performance of railway passenger station buildings is carried out.(3) Seismic fragility curves are generated using PGA and Sα(T1,5%) as earthquake intensity separately. The differences of fragility curves using different earthquake intensity measures are analyzed. Influence of staircase on seismic fragility curves of railway passenger station buildings is carried out. To analyze safety of the three stations, comparisons of seismic fragility curves among the three models are carried out. Finally, the paper summarizes and analyzes collapse resistant safety reserves of the three stations using parameter of CMR.(4) Suggestions are raised to improve aseismic design for small and middle size railway passenger station buildings.