超大承载力端板连接节点抗拉性能及设计方法

TENSILE PERFORMANCE AND DESIGN METHOD OF ULTRA-LARGE CAPACITY END-PLATE CONNECTIONS

超大承载力端板连接节点是一种新型梁柱节点形式,可以应用于大跨或重载钢框架中。在抗震区框架中梁柱节点除承担弯矩之外还可能承担一定的拉力,因此有必要对超大承载力端板连接节点的抗拉性能进行研究。对4个采用不同端板厚度、螺栓直径或螺栓布置形式的超大承载力端板连接节点足尺试件进行了轴拉荷载下的试验研究,记录并分析了各螺栓轴向应变增量分布情况;建立了24个超大承载力端板连接节点的有限元模型并进一步分析了该节点的抗拉性能。基于试验研究和有限元分析的结果得出:在轴拉荷载下端板外伸段靠近梁翼缘中部的螺栓为最不利螺栓,而移除角部螺栓对节点的抗拉性能没有不利影响;提出了该节点受拉时等效受拉螺栓数量的建议计算式,并给出了节点抗拉承载力的设计方法。

The ultra-large capacity end-plate connection is a newly-proposed beam-to-column connection form that can be adopted in steel frame with long span or heavy load. In seismic regions beam-to-column connections in frame may suffer considerable tension force besides the moment,so it is necessary to analyze the tensile performance of the ultralarge capacity end-plate connections. Four full-scale specimens of ultra-large capacity end-plate connections with different end-plate thicknesses,bolt diameters or bolt layouts were tested under tension loads,and the distribution of the axial strain increment in the bolts were recorded and analyzed. A total of 24 finite element models were established to further analyze the tensile performance of the connection form. Based on the results of the experiments and the finite element analysis,the bolts close to the middle of the beam flanges in the extended parts were the most dangerous ones under axial tension, and removing the corner bolts made no adverse influence to the tensile performance. A recommended formula to calculate the effective bolt number in tension was proposed,and the design method for the tensile bearing capacity of the connection was provided.