黏弹性连接弯-剪抗侧体系结构抗震性能

SEISMIC PERFORMANCE OF STRUCTURES WITH LATERAL LOAD RESISTING SYSTEMS OF VISCO-ELASTICALLY CONNECTED FLEXURAL SHEAR

  • 摘要: 为提升传统弯剪型结构体系(如框架-剪力墙体系)抗震性能,提出黏弹性连接弯-剪抗侧结构体系。采用黏弹性元件连接弯曲、剪切2种抗侧单元:在剪力墙上各楼层标高处设置牛腿,支托黏弹性元件下端并使其分担部分楼面荷载,将黏弹性元件上端与楼板刚接并在楼板与剪力墙间预留变形空裕。通过试验研究,证明黏弹性元件的动力剪切滞回特性不受竖向预压力值影响。采用黏弹性元件的纯剪滞回模型和主体结构的“弯曲梁+剪切弹簧”组合模型,建立黏弹性连接弯-剪抗侧结构的动力学模型并实施参数化地震反应分析。结果表明:在正常设计范围内,黏弹性元件的柔度将限制剪切抗侧系统(框架部分)传递至弯曲抗侧系统(剪力墙)的惯性力,使后者的地震内力需求(底部剪力)降低约30%;黏弹性元件的附加阻尼有助于控制结构整体的地震位移反应和楼面加速度反应(楼面加速度降低15%~40%),且该元件的变形需求不超过传统结构层间侧移需求的2倍。

     

    Abstract: To enhance the seismic performance of the conventional flexural-shear type structures, e.g., frame-shear wall system, a visco-elastically connected flexural-shear structural system is proposed. In this system, the flexural- and shear-type lateral load resisting systems (LLRS) are connected by visco-elastic elements (VEE), and corbels are set on the shear wall to support the VEEs, while the VEEs are rigidly connected to the floor deck on the frame. Deforming spaces are set between the floor slab and the shear wall to accommodate the relative displacements between the flexural- and shear-type LLRSs. Some experimental tests are conducted to reveal that the dynamic shearing behavior of the VEE is not influenced by the vertical pressure acting on the top. Using the validated shearing model (for VEE) as well as the combined flexural and shear spring model (for the primary structure), the dynamic analysis model for the visco-elastically connected flexural-shear structural system is established. A parametrical seismic response analysis is conducted. The analysis results show that an approximate 30%-reduction in the seismic force demand of the shear wall could be achieved due to the limited inertial forces transferred from the frame to the shear wall. Thanks to the additional damping introduced by the visco-elastic element, both the global displacement and the floor acceleration are well controlled (reduced by 15% ~ 40%). Demonstrating such good features, the peak deformation of the visco-elastic element is less than twice of the inter-story drift of the primary structure.

     

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