摘要
为研究实心结构古塔在地震作用下的动力反应及破坏机制,以陕西省西安市兴教寺玄奘塔为原型,设计制作了1∶8比例模型结构,进行了振动台试验。通过输入不同烈度的单向、双向及三向地震波,测试了结构楼层的位移及加速度反应,观测了结构破坏现象,分析了结构的动力特性变化规律,对比了各加载工况下结构各楼层地震反应的变化特点。结果表明,设防地震作用下塔体底部楼层首先发生水平开裂与塔身斜向开裂,随着地震烈度的提高,破坏区域随之向上延伸,结构自振频率降低,频响曲线峰值点增多;当地震烈度相同时,不同加载工况下结构的水平反应峰值相差不大,但不同地震波作用下竖向加速度反应峰值相差较大;动力放大系数随楼层高度呈"S"形分布,顶层的水平加速度反应最大,中部楼层的竖向地震反应最大。因此,古塔破坏是在水平向与竖向地震共同作用下发生的,结构的底部及中部楼层为抗震的薄弱部位。
To study the dynamic response and damage mechanism of masonry pagodas with solid structure,the shaking table test has been done to a structure model scaled to 1∶ 8 from the Xuanzang Pagoda at Xingjiao Temple in Xi＇an,Shaan＇xi Province. Excited by unidirectional,bi-directional and tri-directional earthquake waves,displacement response and acceleration response at the floor were tested and the failure pattern of the structure was observed. Then the variation law was analyzed in terms of dynamic characteristics of the structure under different failure situations,and compared for the dynamic response of each floor under different load cases. The results show that horizontal cracks and oblique cracks are observed at the bottom floor of the pagoda affected by earthquake. As the seismic intensity become higher,the damage regions are extended to the top,and the vibration frequency of the structure is decreased. The number of peak value points is increased on the frequency response curve. At the same intensity,the peak value of horizontal response is almost equal under different load cases but the vertical acceleration responses are different under different earthquake waves. The dynamic amplification coefficient curve is distributed in S shape,the maximum value of horizontal response is located at roof and the vertical response is in the middle floor. Therefore,the failures to masonry pagoda are affected by horizontal and vertical earthquake components,and the seismic weak part is the bottom and mid of the structure.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2017年第12期154-162,共9页
Journal of Building Structures
基金
国家自然科学基金项目(51308455)
陕西省自然科学基金项目(2015JM5206)
陕西省博士后基金项目
关键词
砖石古塔
振动台试验
地震反应
破坏机制
masonry pagoda
shaking table test
seismic response
damage mechanism
