高层组合框架-混凝土筒体混合结构抗震性能推覆分析

Seismic behavior analysis of core-RC and composite frame hybrid structure in high-rise buildings based on pushover analysis

为研究高层组合框架-混凝土筒体混合结构的抗震性能,以30层混合结构为分析对象,建立整体空间分析模型进行推覆分析。根据截面承载力与变形能力自定义型钢混凝土构件塑性铰特性值,利用三垂直杆元模拟剪力墙,各杆元分别考虑剪力墙轴向、剪切与弯曲变形,在推覆分析中分别按加速度常量和CQC振型组合方式施加侧向水平荷载,采用能力谱法确定结构的目标位移。结果表明:结构由弹性逐渐进入弹塑性工作状态,最大层间位移角的位置不断降低,中下部层间位移角变化显著,框架与筒体之间剪力重分布主要发生在中下部楼层;框架与混凝土筒体之间连接方式对混合结构罕遇地震性能点的状态影响显著,尤其在结构下部1/3高度范围内,筒体剪切刚度退化程度有差异,刚接模型整体刚度退化程度相比铰接模型严重。

In order to study the seismic behaviors of core-RC and composite frame hybrid structures in high-rise buildings,a 30-story hybrid structure was analyzed.The space finite element models were established.According to section bearing capacity and deformation capacity,the plastic hinge characteristic values of steel reinforced concrete members were defined by user.The three vertical truss element models were used to simulate shear wall,in which axial,shear and bending deformations were considered by each element.The horizontal load was applied respectively by constant acceleration and mode combination of complete quadratic combination during the pushover analysis.The target displacement of structure under earthquake action was determined with capacity spectrum method.The results show that the floor position of the maximum of story drift ratio is continuously dropped while the hybrid structure is gradually into the elastic-plastic state;story drift ratios of the middle to lower floors significant change;shear redistribution occurs at the middle to lower floors;the connection type between frame and core have significant impact on states under rare earthquake action;shearing stiffness degradation of core is significantly different,especially within the lower floors of a third of structure height;overall rigidity degradation of rigid connection model is worse than the hinged connection model.