新型承插式螺栓连接柱-柱节点抗拉性能研究

Research on Tensile Performance of Novel Socket Bolted Column-Column Joint

为实现模块化钢结构单元房间的上下连接,提出一种新型承插式螺栓连接柱-柱节点,以有无注浆、承插深度为参数设计并制作3个足尺节点试件,并对其进行抗拉试验,分析了各节点的破坏形态、应变分布以及承载能力等,探讨了该新型节点的抗拉性能.建立了数值分析模型,进行了轴拉荷载作用下的受力性能参数化分析,研究了承插深度、螺栓直径及内套筒厚度对节点抗拉承载力的影响.基于高强螺栓的抗剪承载力,提出了适用于该新型节点的抗拉承载力计算公式.研究结果表明:该新型节点可将轴向拉力有效传递至高强螺栓,试件破坏时均出现高强螺栓群被剪断,灌浆节点试件发生破坏时,出现钢材与灌浆料界面的黏结破坏及螺栓周围局部灌浆料的压碎;高强螺栓群在拉力荷载作用下呈端部螺栓受剪较大、中心螺栓受剪较小的分布,试件破坏时,各螺栓承受的剪力趋于相等;灌浆节点与无浆节点相比,灌浆料与高强螺栓协同工作性能良好,弹性阶段最大摩擦力平均值提高64.4%,极限抗拉承载力提高14.1%;承插深度由300 mm增至500 mm,节点极限抗拉承载力提高80.9%;承插深度和螺栓直径对节点抗拉承载力影响较大,内套筒厚度对节点抗拉承载力的影响较小;根据提出的节点抗拉承载力计算公式得到的计算值与有限元模拟值吻合良好.

To realize the upper and lower connections of modular steel structure units,a novel type of socket bolted column-column joint was proposed.Three full-scale joint specimens were designed and fabricated with parameters such as with or without grouting and socket depth,and the corresponding tensile test was carried out.The failure mode,strain distribution and bearing capacity of each joint were analyzed,and the tensile performance of the novel joint was discussed.A numerical analysis model was established,and the mechanical performance parameters under axial tensile load were analyzed.The effects of socket depth,bolt diameter and inner sleeve thickness on the tensile bearing capacity of joints were studied.Based on the shear bearing capacity of high-strength bolts,a formula for calculating the tensile bearing capacity of the novel joint was also put forward.Results show that the novel joint can ef-fectively transfer the axial tension to the high-strength bolts.When the specimen was damaged,the high-strength bolt group were cut off.When the grouting joint specimen was damaged,the bonding failure of the interface between steel and the grouting material and the crushing of the local grouting material around the bolt occurred.Under the action of tensile load,the end bolt in the high-strength bolt group was sheared more,while the center bolt was sheared less.When the specimen was damaged,the shearing force of each bolt tended to be equal.Compared with those of the non-grouting joint,the average maximum friction at the elastic stage and the ultimate tensile bearing capacity of the grouting joint increased by 64.4%and 14.1%respectively because the high-strength bolt worked well with the grout-ing material.When the socket depth increased from 300 mm to 500 mm,the ultimate tensile bearing capacity of the joint increased by 80.9%.It is concluded that the socket depth and bolt diameter have a great influence on the tensile bearing capacity of the joint,while the effect of the thickness of the inner sleeve is small.In addition,the value cal-culated according to the proposed calculation formula for the tensile bearing capacity of the joint is in good agreement with the simulation value obtained using the finite element method.