轻质填充墙框架结构抗震性能的振动台试验研究

SHAKING TABLE SEISMIC TESTON PERFORMANCE OF FRAME-STRUCTURE WITH LIGHT-WEIGHT INFILLED WALLS

设计与原型相似比为1/4的三层两跨轻质填充墙框架结构缩尺模型在振动台上进行不同级次地震动输入下的抗震性能试验研究。通过对比空框架和填充墙框架结构的模态测试结果,考察了填充墙对框架频率的加强效应;根据对填充墙的破坏现象及试验结果分析,研究了填充墙在主体结构破坏不同阶段的频率衰减、刚度退化情况及层间位移角、各层放大倍数变化规律,并分析了填充墙和框架协同工作的过程。研究结果表明:填充墙充当了结构抗震的第一道抗震防线,通过填充墙耗能延缓了主体结构裂缝出现的时间,但填充墙与框架主体结构的柔性连接处破坏,易造成框架柱在此处出现塑性铰,不易实现"强柱弱梁"破坏机制,成为框架结构抗震的薄弱环节。

A scaled model of a three-story and two-cross frame structure with light-weight infilled walls was designed under a similarity ratio of 1/4 and then tested on a shaking table under different ground motion levels to explore its aseismic performance. Comparing the mode tested results of non-filled and infilled frame structures, the enhancing effect of infilled walls on the frequency of a frame was studied. By analyzing the failure phenomena of the main structure, the frequency attenuation, stiffness degradation, inter-story drift angles and story amplification factors of infilled walls were investigated during different failure stages. The cooperative process of infilled walls and the frame was discussed as well. The results show that the infilled walls firstly dissipated the seismic energy so that the time of frame cracking tends to be postponed, while the flexible joints between infilled walls and frames failed, creating plastic hinges in the joints of frames and columns. The failure mechanism of ‘strong column and weak beam' cannot be achieved, which become the weak points of aseismic performance of frame structures.