冷弯薄壁型钢四肢拼合梁柱节点抗弯性能研究

Flexural behavior of cold-formed thin-walled steel quadruple-limb build-up beam-column connections

基于梁、柱截面拼合形式提出一种新型梁柱连接节点,以实现其拼合截面梁柱的快速装配。为研究其抗弯性能,对4组节点试件进行单调加载试验。通过试验得到节点的破坏模式、弯矩-转角关系,分析柱板厚、节点域螺钉数量、连接件端板厚度对节点抗弯性能的影响,为之后建立有效的冷弯薄壁型钢节点性能分析模型库提供数据,并对节点承载力进行理论计算。研究结果表明:该类节点的破坏模式主要有螺钉拔出或剪断、端板抗弯失效。柱板厚度增加1倍后,节点初始刚度增加26%,极限弯矩提高39.3%;节点域螺钉数量由3排(6个)增加到4排(8个)后节点初始刚度仅增加9.9%,极限弯矩仅提高6.4%;连接件端板厚度由4 mm增加到8 mm时,节点初始刚度提高45.5%,极限承载力没有明显变化。说明柱板厚和连接件端板厚度对节点初始刚度的影响较大,柱板厚对节点极限承载力也有一定的影响,而螺钉数量对节点的初始刚度和极限承载力影响不大。柱板厚度同时翻倍后,增加节点域螺钉数量可以提高节点的初始刚度和极限承载力。4组节点的弯矩转角曲线呈现明显的非线性特征,基于欧洲钢结构Eurocode3规范确定该类节点为半刚性节点。通过对节点进行受力分析计算节点极限弯矩,将计算值与试验值进行对比发现,理论计算值与试验值较为吻合。试验研究的连接件也可用于箱型冷弯轻钢梁柱连接节点,有利于快速装配。

Based on the combination of beam and column sections,a new type of beam-column connections wasproposed in order to realize the rapid assembly of the beam-column with its combination section.In order to study its flexural performance,monotonic loading tests were carried out on four groups of connections,and the failure modes and bending moment-rotation relationship of the connections were obtained through the tests.The influences of column thickness,the number of screws in the connection domain and the thickness of the end plate of the connection on the flexural performance of the connection were analyzed.This provided data for establishing an effective performance analysis model library of cold-formed thin-walled steel connections,and theoretically calculated the bearing capacity of the connection.The results show that the failure modes of this kind of connections mainly include screw pulling out or shearing,and bending failure of end plates.When the thickness of the column is doubled,the initial stiffness of the connection increases by 26%and the ultimate bending moment increases by 39.3%.When the number of screws in the connection domain is increased from three rows(6)to four rows(8),the initial stiffness of the connection only increases by 9.9%,and the ultimate bending moment only increases by 6.4%.When the thickness of the end plate increases from 4 mm to 8 mm,the initial stiffness of the connection increases by 45.5%,and the ultimate bearing capacity has no obvious change.It shows that the thickness of the column plate and the end plate of the connection have great influence on the initial stiffness of the connection,and the thickness of the column plate also has certain influence on the ultimate bearing capacity of the connection,while the number of screws has little influence on the initial stiffness and ultimate bearing capacity of the connection.When the thickness of the column is doubled at the same time,increasing the number of screws in the connection domain can improve the initial stiffness and ultimate bearing capacity of the connection.The bending moment-angle curves of four groups of connections show obvious nonlinear characteristics,and this kind of connections is determined to be semi-rigid based on Eurocode3 specification for steel structures in Europe.The ultimate bending moment of the connection is calculated through the stress analysis of the connection.By comparing the calculated value with the experimental value,it is found that the theoretical calculated value is in good agreement with the experimental value.The tested connections can also be used for box-type cold-formed light steel beam-column connections,which is conducive to rapid assembly.