西安火车站东配楼复杂连体结构振动台试验研究

西安火车站改扩建东配楼项目由三个平面不规则的单体建筑通过大跨度桁架进行连接，结构质量与刚度分布差异较大，且平动与扭转振动反应的耦联效应显著。为研究不规则连体结构的抗震性能，选取子结构进行了1∶10缩尺模型振动台试验，分析设防、罕遇及超罕遇地震作用下结构的破坏模式、动力特性以及加速度、位移、内力响应，评价连体结构的抗震性能。结果表明：在8度设防地震作用下，结构的自振频率呈线性退化，单体频率下降约20%。在8度罕遇地震作用下，框架梁端形成塑性铰，小三角区角柱首先进入塑性工作状态，各区频率降低超过了57%，实测层间位移满足现行GB 50010—2010《建筑抗震设计规范》要求。在9度超罕遇地震作用下，叠层桁架由于位移过大导致扭转效应显著，连接支座处发生破坏，但结构并未发生整体倒塌。连体结构的薄弱部位于第2层，小三角区侧向刚度较弱，建议在该区增设支撑或剪力墙。采用柔性连接能有效降低大跨桁架的地震作用，但面外扭转效应显著，受竖向地震作用影响较大。

Shaking table test on complex connected structure of East annex building of Xi'an Railway Station

The renovation of Xi'an railway station East annex building consists of three irregularly-shaped buildings connected by long-span trusses. The structural weight and stiffness distribution are notably irregular, and the flat twisted coupling effect is significant. To study the seismic performance of the structure, shake table test of 1/10 scale model was performed. The failure mode, dynamic characteristics, acceleration, displacement, and internal force response of the structure under fortification, rare and super rare intensity conditions were analyzed, and the overall seismic performance of the structure was evaluated. The results show that under the 8-degree design earthquake, the natural frequency of the structure degrades linearly and decreases by about 20%. Under the rare earthquake of 8 degrees, plastic hinges are formed at the ends of the frame beams. The corner columns in the small triangular area first yield, and the frequency degradation exceeds 57%. The measured inter-story displacement meets the requirements of the current Code for seismic design of buildings GB 50011-2010. Under the action of a rare earthquake at 9 degrees, the laminated truss has a significant torsion effect due to excessive displacement, and the connecting supports are damaged, but the structure collapse is not observed. The weak part of the structure is on the second floor, and the lateral stiffness of the small triangle area is weak. It is recommended to add a support or shear wall in this area. The flexible connection can effectively reduce the seismic action of long-span trusses, but the out-of-plane torsional effect is significant, and the vertical earthquake action has a notable effect.