Zhao Zengyang, Zhang Wenyuan, Ding Yukun, Li Hongwei
Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Harbin Institute of Technology, Harbin 150090, China.
Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology, Harbin Institute of Technology, Harbin 150090, China.
Materials (Basel). 2022 Jun 21;15(13):4377. doi: 10.3390/ma15134377.
In order to study the influence of brace failure on the seismic response of concentrically braced frames and the improvement of the residual structure's resistance to collapse due to reserve capacity, a series of concentrically braced frame prototypes with different story numbers is designed. A matrix of six finite-element concentrically braced-frame (CBF) models is established, which is varied by the number of stories and the level of reserve capacities. Accuracy of the numerical model is verified by comparing the responses of the shaking-table test of the concentrically braced frames, under 10 different working conditions. Then, a nonlinear time-history analysis, considering brace failure in one specified story, is carried out. The results show that the story-drift angle of the failure story as well as its adjacent stories increases greatly in the ideal pinned model. The above phenomenon is particularly serious, when the failure occurs at the top or bottom of the structure. With the reserve capacity brought by column continuity, and the semi-rigid rotation capacity of the beam-to-column and column-to-base connections are taken into consideration, the increase in story-drift angle caused by the brace failure is effectively reduced. However, the inherent reserve capacity has little influence on the dynamic characteristics of concentrically braced frames in the elastic stage.
为了研究支撑失效对中心支撑框架地震响应的影响以及由于储备能力而对残余结构抗倒塌能力的改善，设计了一系列不同层数的中心支撑框架原型。建立了一个由六个有限元中心支撑框架（CBF）模型组成的矩阵，该矩阵根据层数和储备能力水平而变化。通过比较中心支撑框架在10种不同工况下的振动台试验响应，验证了数值模型的准确性。然后，进行了考虑一个指定楼层支撑失效的非线性时程分析。结果表明，在理想铰接模型中，失效楼层及其相邻楼层的层间位移角大幅增加。当失效发生在结构顶部或底部时，上述现象尤为严重。考虑到柱连续性带来的储备能力以及梁柱和柱脚连接的半刚性转动能力，支撑失效引起的层间位移角增加得到有效减小。然而，固有储备能力在弹性阶段对中心支撑框架的动力特性影响很小。
