大跨装配式混凝土结构横隔板效应分析

Diaphragm effectiveness in large-span precast concrete structures

办公楼等大跨装配式混凝土结构的强震响应很大程度上取决于楼/屋盖的连接结构构件性能、连接节点构造措施、以及由其控制的楼盖横隔板,应提出大跨装配式混凝土结构楼/屋盖及其连接构件的合理设计方法。基于线性参数化分析,考虑了9种板-板连接、5种墙-墙连接及3种板-墙/梁连接共135种不同刚度连接组合下模态分析,评价了节点连接刚度对于结构动力特性及楼盖横隔板效应的影响;结合水平地震动反应谱分析及弹性时程分析,分析了不同楼/屋面连接的结构地震响应。分析表明:刚性节点连接变形控制能力强,对楼/屋盖刚度和质量均匀性的分布贡献大,有利促进了横隔板的积极效应;超柔性连接的楼/屋盖刚度和变形的不均匀性显著,可出现扭转等非预期变形;相对于刚性连接,工程常用半刚性连接下结构侧移较大,且非刚性连接使得楼层加速度放大明显,显著影响了楼盖设计的荷载取值。建议大跨装配式混凝土结构构件间采用可有效抵御构件平面内错动、平转动刚度大、有利于实现积极横隔板效应的新型连接。

The seismic performance of large-span precast concrete structures, such as office buildings, largely depends on the performance of the floor/roof connectors, the construction details of connectors, and the resultant diaphragm effectiveness. A reasonable design method for the floor/roof of large-span precast concrete structures as well as their connectors should be proposed. A parametric study based on linear analysis was carried out. A total of 135 modal analyses were performed to evaluate the influence of connector rigidity on the dynamic characteristics and diaphragm actions of the structures, considering nine types of floor-to-floor connections, five types of wall-to-wall connections, and three types of floor-to-wall/beam connections. Response spectrum analysis and elastic time history analysis were conducted under horizontal seismic actions to obtain the structural responses of different floor/roof connectors. Results show that the rigid connectors had remarkable deformation control ability, which contributes greatly to the distribution of floor/roof stiffness and mass uniformity, and promotes diaphragm effectiveness positively;the stiffness and deformation of floor/roof with extremely-flexible connections were significantly uneven, which may cause unexpected deformation such as torsion;the horizontal displacement of the structure with semi-rigid connectors was larger than that with rigid connectors, and non-rigid connectors made the floor acceleration increase obviously, affecting the designed load value of the floor significantly. It is suggested that new types of connectors, which can effectively resist the in-plane dislocation of elements, possess considerable horizontal rotation stiffness, and promote diaphragm effectiveness positively, should be adopted for large-span precast concrete structures.