自复位钢框架节点有限元模拟及参数分析

Modeling and parametric study of beam-to-column connection for self-centering steel moment frames

研究了一种具有自复位能力的钢框架节点的力学性能。该节点在梁柱间通过角钢栓接,并沿梁长布置高强预应力钢绞线。通过对钢绞线施加预应力将梁柱压紧,使节点具备足够的抗弯刚度以满足正常使用情况下的功能性要求,钢绞线同时提供回复力,使节点在地震后具有自复位能力。采用通用有限元分析软件Abaqus 6.9建立节点模型,对9个足尺钢框架边节点进行了循环加载以模拟节点的复位能力。考察的参数有:初始预应力值、角钢厚度、预应力钢绞线距离及数量。研究表明:通过合理参数设计,这类节点的初始刚度与焊接节点相当,在层间位移角达到5%的情况下,主体结构梁和柱仍保持弹性,角钢则进入塑性状态以耗散能量;地震作用后,节点可以回复到其初始位置。由于主体结构没有破坏,且节点在预应力钢绞线作用下自动回复原位,故震后仅需更换角钢便可使节点恢复至无损状态。

A new type of beam-to-column connection for steel moment frames is proposed.The new connection uses bolted top and seat angles,and post-tensioned（PT） high-strength steel strands running along the beam.The PT strands tie the beam flanges on the column flange to resist moment and provide self-centering force.A general FEM analysis program called Abaqus 6.9 is adopted to model 9 new connections subjected to cyclic loading.The effects of the prestressing forces,the thickness of the angles,and the distance and the amount of the PT strands on the behaviour of the connections are investigated.The results show that the connections have an initial stiffness similar to that of the welded connections.Under 5% drift,the columns and beams remain elastic while the angles sustain inelastic deformations for energy dissipation.After the unloading,the connections have zero deformation.They can be restored to the original condition by simply replacing the angles.