带开槽耗能板的自复位方钢管混凝土柱-钢梁节点抗震性能有限元分析

Finite Element Analysis of Seismic Behavior of Self-Centering Concrete-Filled Square Steel Tubular Column-Steel Beam Joint with Slotted Energy Dissipation Plate

自复位结构是一种新型可恢复功能结构,它能够有效控制结构震后残余变形,震后不需或经少量维修即可恢复正常使用。近年来,自复位结构成为国内外地震工程界研究的热点。目前的自复位结构主要通过两种方式耗能:金属的塑性变形或设置摩擦阻尼器。但以上两种耗能方式通常存在较大的复位抗力,从而对结构的复位构件提出更高的要求,同时对节点的自复位性能产生不利影响,如何减小复位抗力是此类结构目前亟需解决的重要问题。基于上述问题,提出了一种新型带开槽耗能板的自复位方钢管混凝土柱-钢梁节点,通过在耗能板上开设长槽,可有效减小节点的复位抗力。该节点主要由方钢管混凝土柱、H型钢梁、悬挑梁段、开槽耗能板、盖板、抗剪连接板和钢绞线等构成。为探究该节点的破坏形态、抗震性能、自复位性能及耗能能力,采用有限元软件ABAQUS对带开槽耗能板的自复位方钢管混凝土柱-钢梁节点进行模拟分析,得到弯矩-转角滞回曲线、承载力及特征弯矩、单周滞回耗能及残余变形等。共设计5个节点模型(节点SCJ-1~SCJ-5),对比分析耗能板开槽数量、耗能段宽度、耗能板厚度及钢绞线初始预应力这些参数对节点自复位性能和抗震性能的影响。结果表明:在梁端往复荷载作用下,节点的滞回曲线呈典型的"双旗帜"形,该节点具有良好的承载能力、自复位能力和耗能能力;当加载至4.00%层间位移角时,梁柱主体构件基本处于弹性状态,耗能板发生明显的塑性变形,说明该节点可有效地将损伤控制于局部,从而降低主体构件的塑性损伤;耗能板的开槽数量越多,节点的耗能能力越差,自复位性能越好,而对节点的承载力及特征弯矩没有显著影响;随着耗能段宽度和耗能板厚度的增大,节点的耗能能力增强,自复位能力降低,节点承载力提高。增大钢绞线的初始预应力,节点的初始刚度、承载力和脱开弯矩提高,自复位能力增强,而对节点的耗能能力影响较小。

Self-centering structure is a new type of resumable structure,which can effectively control the residual deformation after earthquake and can be restored after a little maintenance. In recent years,self-centering structure has become a hot spot in the field of seismic engineering. At present,self-centering structure dissipates seismic energy mainly in two ways: plastic deformation of metal or friction damper. However,the above two modes usually have a large reduction resistance,which puts forward higher requirements on the reset members and adversely affects the self-centering performance of the joints. How to reduce the reduction resistance is an important problem that needs to be solved for such structure.Based on the above problem,a new type of self-centering concrete-filled square steel tubular column-steel beam joint with slotted energy dissipation plates is proposed. The reduction resistance of the joints can be effectively reduced by setting slots on the energy dissipation plates. The joints is mainly composed of square concrete-filled steel tube column,steel beam,cantilever beam,slotted energy dissipation plates,cover plates,shear plates and strands,etc. In order to explore the failure mode,seismic performance,selfcentering performance and energy dissipation capacity of the joints,finite element software ABAQUS was used to simulate and analyze the self-centering square concrete-filled steel tubular column-steel beam joints. The moment-angular hysteretic curves,bearing capacity and characteristic moment,single-cycle hysteretic energy dissipation and residual deformation were obtained. Five joints were designed to compare the influences of the number of slots,the width and thickness of energy dissipation plates and the prestress of strands on seismic performance of the joints.The results show that under seismic behavior,the hysteretic curves show "double flags"shape,and the joints have good bearing capacity,self-centering capacity and energy dissipation capacity. The main components are basically in elastic and the energy dissipation plates have obvious plastic deformation under 4.00% displacement angle,indicating that the joints can control the damage locally and reduce the plastic damage on main components. The more slots of energy dissipation plates,the worse energy dissipation capacity and the better self-centering performance. However,it has no significant influence on the bearing capacity and characteristic moment of the joints. With the increase of width and thickness of energy dissipation plates,the energy dissipation capacity increases,the self-centering capacity decreases,and the bearing capacity increases. With the increase of prestress in strands,the initial stiffness,bearing capacity and decompression moment are increased,and the self-centering capacity is enhanced,but the energy dissipation capacity is less affected.