在罕遇地震作用下,根据现行规范设计的高层钢框架结构会经历较大的非弹性变形,其非弹性性能在一定程度上难以预测和控制。根据功能平衡原理,该文提出了一种高层钢框架结构基于性能的塑性设计方法。预先选定目标侧移和屈服机制作为结构两个关键的性能极限状态。根据能量相等原则,即使结构单调达到目标侧移所需作的功等于等效弹塑性单自由度体系达到相同状态所需要的能量,来计算给定的地震水准下的设计基底剪力。采用塑性设计法设计框架构件和节点以便达到预期的屈服机制和性能。采用此方法对一幢10层钢框架结构进行了设计,然后采用动力时程分析法和静力非线性分析法验证了该方法的可行性,为高层钢框架结构基于性能的塑性抗震设计法提供了一定的依据。
Under major earthquakes, high-rise steel moment frames designed to the current codes will undergo inelastic deformations in an uncontrolled manner. According to the principle of work-energy conservation, this paper presents a performance-based plastic design (PBPD) method for the design of high-rise steel frames. The method uses pre-selected target drift and yield mechanisms as key performance indicators. The design base shear for a selected hazard level is calculated by equating the work needed to push the structure monotonically up to the target drift to that required by an equivalent single degree of freedom to achieve the same state. Plastic design is performed to detail the frame members and connections in order to achieve the targeted yield mechanism and behavior. The method has been successfully applied to a ten-storey steel moment resisting frame, and validated by inelastic dynamic analyses and pushover analysis. In the cases, the frames develop desired strong column sway mechanisms, and the story drifts are well within the target values, thus meeting the desired performance objectives The addressed method herein can form a basis for the performance-based plastic design of high-rise steel frames.