风荷载与地震耦合作用下超高层建筑的结构损伤与玻璃幕墙坠落研究

Study on structural damage and falling of glass curtain wall of super high-rise building under coupling action of wind and earthquake

超高层建筑服役周期长,在其全寿命周期内有可能遭受风和地震同时作用,需针对主体结构和玻璃幕墙受风、地震单独和耦合作用进行研究。基于结构高度为300.5 m超高层框架-核心筒结构,依据相关规范要求建立主体结构与玻璃幕墙整体有限元分析模型,根据场地条件选取3组三向地震动记录,并通过已完成的1∶440缩尺模型风洞试验获得10、50 a和100 a重现期的风压时程。采用非线性时程分析方法,研究风荷载、地震单独与耦合作用对主体结构和玻璃幕墙受力性能的影响。结果表明:玻璃幕墙对主体结构的影响较小,而主体结构对玻璃幕墙的影响则较大,其变形超过玻璃幕墙由荷载直接作用所产生的变形。在风荷载或地震单独作用下,主体结构的非线性响应和玻璃幕墙的破坏情况均随荷载强度增大而增大;在地震作用下,主体结构进入非线性状态后,结构顶点位移和层间位移角的增幅超过基底剪力的增幅,但低于峰值加速度的增幅;在风荷载作用下,主体结构处于弹性工作状态,基底剪力和倾覆弯矩随风压增大呈线性增长,但因变形响应特性不同,变形产生非线性增长,结构扭转效应增大;在风荷载与地震耦合作用下,主体结构和玻璃幕墙的非线性响应超出风荷载或地震单独作用的简单叠加,结构变形为单独作用简单叠加值的110%~134%。结构刚度变化较大的加强层及其邻近1~2层,侧风面负风压较大,玻璃幕墙容易破坏而坠落,设计时需注意加强。

Considering the long service life of the structure and the possibility of simultaneous actions of wind and earthquake in the whole life cycle, the individual and coupled actions of wind and earthquake loads of the main structure and glass curtain wall was studied. Based on a 300.5 m super high-rise frame-core wall structure, a finite element analysis model was built by adding the glass curtain wall according to the codes. Three groups of three-dimensional ground motion records were selected according to the site conditions, and the wind pressure time-history of 10 years, 50 years, and 100 years return periods was obtained through a 1∶440 scale wind tunnel model test. Subsequently, the effects of the individual and coupled actions of wind and earthquake on the behavior of the main structure and glass curtain wall were studied by the nonlinear dynamic analysis method. The results show that the influence of the main structure on the glass curtain wall was greater than that of the glass curtain wall on the main structure. The inter-story deformation of the main structure was larger than the deformation of the glass curtain wall itself. Under the individual actions of wind and earthquake, the nonlinear response of the main structure and the failure range of the glass curtain walls increased with increasing load. Under the earthquake action, the structure was damaged and the growth of structural top displacement and story drift was greater than that of the base shear force but less than the growth of top acceleration. Under the action of wind, the main structure was kept in the elastic stage, and the base shear and the overturning moment increased linearly. For the deformation response characteristics, the torsional effect increased and the deformation increased nonlinearly. Under the coupling action of wind and earthquake, the nonlinear response of the main structure and glass curtain wall was greater than the simple superposition of wind and earthquake alone. The top displacement and the maximum story drift were 110%~134% of the sum of wind and earthquake alone. The failure of the glass curtain wall is more likely to occur on the reinforced layer, the nearby 1~2 layers, and the side suction surface which needs to be enhanced in design.