长持时地震作用下钢结构梁柱节点塑性变形能力

Plastic deformation capacity of steel beam-to-column connection under long-duration earthquake

延性破坏是钢框架中梁柱节点最常见的破坏模式之一。目前主要通过试验方法来评价发生延性破坏钢梁的塑性变形能力,其中材料的屈强比、梁的弯矩梯度和梁柱节点的详细构造等都是重要的参数。但是在实际试验中要涵盖所有这些参数是不可能的,也是不现实的。此外,影响钢梁塑性变形能力的另一个重要的因素是加载机制。最近几年,长持时地震对结构构件的影响备受关注。长持时地震作用下,钢梁往往承受长时间的低幅循环荷载,然而,目前的试验研究中大多采用各个国家规范推荐的振幅递增加载机制。通过数值分析方法,对长持时地面运动作用下钢梁的塑性变形能力进行评估。

Ductile fracture is one of the most common failure modes of steel beam-to-column connections in moment resisting frames. Most proposed evaluation methods of the plastic deformation capacity of a beam until ductile fracture are based on steel beam tests,where the material' s yield strength ratio,the beam' s moment gradient,and beam-to-column connection details are the most important parameters. It is impossible and unpractical to cover all these parameters in real tests.Therefore,a new attempt to evaluate a beam' s plastic deformation capacity through analysis was introduced. Another important issue is about the loading histories. Recent years,the effect on the structural component under long-duration ground motion has drawn great attentions. Steel beams tend to experience a large number of loading cycles with small amplitudes during long-duration earthquakes. However,current research often focuses on the beam' s behavior under standard incremental loading protocols recommended by respective countries. The plastic deformation capacity of steel beams subjected to long duration ground motions was evaluated through analytical methodology.