| ABSTRACT:Nowadays in China, the high speed rail has achieved many top records among all the countries in the world:the fastest one in development speed, the most comprehensive one in system technology, the strongest one in integration ability, the longest one in operation mileage, the fastest one in operation speed and the biggest one in the construction scale. Integrated Station-Bridge Structure which combines building structure and bridge structure is widely used for extensive space and diverse functions. At present, the researches on mechanism of earthquake disaster, failure mode, seismic design and analysis at home and abroad is still at a preliminary stage. Seismic performance evaluation for high speed railway station mostly adopts displacement as the unique index to determine failure mode, without considering the energy dissipation mechanism, resulting the lack of understanding in the damage and collapse mechanism in-depth. Furthermore, the objective of seismic performance design for the station is lack of the assurance measures, and the checking indices are not clear. Moreover, the risk analysis of the medium and small station structures under the designated earthquake is not reported extensively. Based on the three dimensional infinite element model of Tianjin South Station, the paper evaluates the seismic performance of this structure through seismic response analysis. The main researches are as follows:(1)Using Midas/Gen software, the reasonable calculation model is established. Through IDA analysis, the performance point of each limit state of the whole structure and typical pier columns could be gained, from which the relations of performance index between the overall structure and the individual components could be contrasted. Through changing IM index, the corresponding value could be gotten. The limit value of the displacement at the top of the pier under each limit status is given, so the reference and check will be easy to be done. The results show that the trend of IDA curves for individual components are the same as the whole structure, and the performance values are almost equal.(2)Based on the results of IDA analysis, the fragility of overall structure and typical pier columns based on displacement could be analyzed, and the fragility curves could be drawn, so that the seismic performance of structures under three levels of earthquake could be explored, meanwhile introducing Collapse Margin Ratio(CMR) to evaluate collapse resistant capacity. The results show that when regarding the max story drift ratio as the performance index, the example structure has excellent seismic performance at7degree(0.15g), and the collapse resistance is also well under great earthquake.(3)Introducing the Park-Ang double-parameter failure criterion, the damage models are constructed. Through analyzing the evaluation of each parameter and the ratio of energy part in all damage index in detail, the damage index in limit state is calculated, then comparing with the damage levels given by Park. Through the analysis for seismic fragility and collapse resistant capacity based on Park-Ang damage index, the comparison with the result based on displacement is analyzed. The results show that the damage grade proposed by Park is not suitable for model structure, So the new method on damage grade classification and state description are given. The collapse resistant capacity based on damage index of Park-Ang is insufficient under great earthquake, so the hysteric energy can’t be ignored when computing damage index. |
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