端板连接节点中抗拉承载力和撬力计算的探讨  

Disscussion on the Tension Capacity with Prying Force of Bolted End-Plate Connections

作　　者：张圣华 柴昶 Shenghua Zhang;Chang Chai(JCHX Mine Engineering Institute Co.,Ltd.,Beijing 100070,China;China Steel Construction Society,Beijing 100088,China)

机构地区：[1]金诚信矿山工程设计院有限公司,北京100070 [2]中国钢结构协会,北京100088

出　　处：《钢结构（中英文）》2022年第5期44-50,共7页Steel Construction（Chinese & English）

摘　　要：弯矩作用下的高强度螺栓端板连接中,端板在拉力作用下会发生弯曲变形并产生撬力,相对刚度较弱的连接节点设计中,撬力作用不可忽视。按国内标准设计的端板连接节点普遍存在螺栓数量多、端板厚度大的问题,因而有必要分析撬力Q、节点承载力Nt、螺栓拉力Nb以及螺栓抗拉承载力Nbt之间的关系,并通过对现行标准算式及其参数进行对比研究,找出导致我国标准偏于保守的原因。受拉T型件模型可用于模拟高强度螺栓端板连接节点,国内外的受拉T型件节点试验和理论分析均表明:撬力效应明显的受拉T型件节点,其第一个塑性铰均首先出现在T型件翼板根部附近。随着外拉力Nt逐步增加,T型件翼板由弹性状态逐步进入弹塑性状态,撬力也从无到有,逐步增大,直至螺栓被拉断或T型件翼板完全破坏(在螺栓孔附近出现第二个塑性铰)。外拉力Nt分为Nt1和Nt2两部分,其中Nt1对应T型件翼板根部出现塑性铰时的外拉力,Nt2则与撬力Q在螺栓附近形成弯矩平衡,外拉力Nt的力臂为T型件根部至螺栓孔的距离,撬力Q的力臂为螺栓孔至T型件边缘的距离。根据节点破坏模式和破坏状态下螺栓孔处的弯矩平衡条件,得到节点抗拉承载力Nt、撬力Q、螺栓拉力Nb及破坏模式临界板厚的计算式,根据节点抗拉承载力算式可以绘制节点承载力曲线,并得到三种破坏模式的控制条件及三种破坏模式之间的关系。国内外对于考虑撬力效应的高强度螺栓连接设计方法存在差异,与国外标准的对比结果表明:1)中美标准均是已知外力Nt计算板厚;欧洲标准是已知板厚计算节点抗拉承载力Nt。三者虽然形式上有差别,但计算式原理相同,可以相互转换。2)GB 50017—2017《钢结构设计标准》中高强螺栓抗拉承载力Nbt已计入撬力效应;其他相关钢结构标准中有关节点承载力计算式仍以Nbt作为高强螺栓抗拉承载力上限�In the end plate connection with high-strength bolts subjected to bending moment,the end plate occurs bending deformation and produces prying force.In the design of connection joints with weak relative stiffness,the prying force can not be ignored.The end plate connection joints designed according to domestic specifications generally have the problems of large number of bolts and large thickness of end plate.It is necessary to analyze the relationship between prying force Q,joint bearing capacity Nt,bolt tension Nb and bolt tensile bearing capacity Nbt,and find out the reasons for the conservatism of China’s standards through the comparative study of the current specifications formulas and their parameters.The tensile T-stub joint model can be used to simulate the high-strength bolted end-plate connection joint.The tensile T-stub joint test and theoretical analysis at home and abroad show that the first plastic hinge of the tensile T-stub joint with obvious prying force effect first appears near the root of the wing plate of the T-stub.With the gradual increase of the external tension Nt,the wing plate of T-stub gradually enters the elastic-plastic state from the elastic state,and the prying force also gradually increases from nothing until the bolt is broken or the wing plate of T-stub is completely damaged(a second plastic hinge appears near the bolt hole).The external tension Nt is divided into two parts Nt1 and Nt2,where Nt1 corresponds to the external tension when plastic hinge occurs at the wing plate root of T-stub,Nt2 forms a moment balance with the prying force Q near the bolt.The force arm of the external tension Nt is the distance from the root of T-stub to the bolt hole,and the force arm of prying force Q is the distance from the bolt hole to the edge of T-stub.According to the joint failure mode and the bending moment balance condition at the bolt hole in the failure state,the calculation formulas of joint tensile bearing capacity Nt,prying capacity Q,bolt tension Nb and the critical plate thicknes

关 键 词：端板连接 T型件抗拉承载力 撬力 塑性铰 

分 类 号：TU391[建筑科学—结构工程]