BRS板部分自复位连接新型卷边PEC柱-钢梁组合框架边节点抗震机理试验

为了研究BRS板部分自复位连接新型卷边PEC柱-钢梁组合框架边节点的抗震性能,对考虑PEC柱布置方式和柱顶竖向力的3个缩尺试件进行水平低周往复荷载下的抗震性能试验研究。基于试验结果,从试件的承载力、刚度衰减规律、自复位功效、耗能能力和节点传力机理等方面分析试件的抗震机理。研究结果显示:(a)BRS板部分自复位连接可通过BRS板屈服耗散地震能和预拉杆实现自复位功效,且整个加载过程中结构主要构件处在弹性状态。(b)PEC柱顶竖向力明显提高了其初始抗弯刚度,且其二阶效应加快了连接的耗能发展进程,而PEC柱的布置对初始抗弯刚度、刚度退化和耗能发展进程影响较小。(c)试件SYJ1加载至中震层间侧移限值1/50时其残余相对侧移角小于0.005 rad,而加载至大震层间侧移限值1/30时其残余相对侧移角仍小于0.01 rad,表明该试件具有极佳的自复位功效;试件SYJ3的自复位功效稍劣于试件SYJ1,前者在加载至中震层间侧移限值1/50之前时自复位功效尚好,但加载后期其自复位功效退化明显。

Experimental study on seismic mechanism of new PEC column-steel beam joint with partial self-centering BRS connection

In order to investigate the seismic performance of the joint of a new PEC column-steel beam frame with a partial self-centering BRS energy-dissipation connection, the axial compression on the top of the PEC column and its layout were taken into consideration to design three reduced-scale specimens, and tests were conducted with low-cycle reversed lateral loading. Based on the experimental results, the seismic mechanisms of specimens were analyzed in terms of the load-carrying capacity, bending stiffness degradation, self-centering function, energy-dissipation capacity, and force-transfer mechanism of the joint. The results indicate that: (a)Partial self-centering BRS connectivity can provide self-centering functionality through dissipation of earthquake energy and reduction of structural response, and the main components are in the elastic state throughout the loading process. (b)The axial compression on the top of the PEC column significantly increases the initial bending stiffness, and accelerates the energy dissipation process, while the layout of the PEC column has little effect on the initial bending stiffness, stiffness degradation, and energy dissipation process. (c)The residual drift angle of specimen SYJ1 is less than 0. 005 rad when the loading drift reaches the interstory drift limit of 1/50 at the medium earthquake level and 0. 01 rad when the loading drift reaches the interstory drift limit of 1/30 at the maximum earthquake level, indicating its sound self-centering functionality. The self-centering functionality of specimen SYJ3 is slightly inferior to that of SYJ1, and the self-centering functionality of specimen SYJ3 is strong before the loading drift reaches the interstory drift limit of 1/50, but degenerates significantly in the late stage of loading.