带悬臂的张弦梁拉索-支座节点力学性能研究

Study on the Mechanical Properties of a Cable-Support Joint of Beam String Structure with Cantilever

为得到带悬臂的张弦梁拉索-支座复杂节点在不同工况下的力学性能变化规律,以及在设计荷载组合下的破坏模式,结合某大跨度张弦梁实际工程,通过建立多尺度有限元模型以及现场试验的方法研究了该节点在张拉过程中的应力、应变分布特征;通过局部节点有限元分析得到了节点的极限承载能力及破坏模式;并针对其受力特征对节点构造及壁厚进行优化。结果表明在施工及使用阶段,该节点应力均处于弹性范围内,满足力学性能要求;节点的破坏荷载约为设计荷载组合的3.2倍,破坏模式为耳板上拉索孔区域受拉破坏;优化后节点的应力分布更加均匀且合理,承载能力提高。

In order to obtain the mechanical properties of a cable-support joint of beam string structure with cantilever under different working conditions,the stress and strain distribution characteristics of the joint during the tensile process were obtained by establishing a multi-scale finite element model and carrying out a field test,combining with an actual project of a long-span beam string structure.The ultimate bearing capacity and failure load of the joint were obtained through the local joint finite element analysis,and the structure and thickness of the joint were optimized according to its stress characteristics.The results show that the stress of the joint connecting to cable is within the elastic range during the construction and service stage,which fully meets the mechanical property requirements.The failure load of the joint is about 3.2 times of the design load combination,and its failure mode is tensile failure at the area of cable hole on lug plate.After optimization,the stress distribution of the joint is more uniform and reasonable,and the load bearing capacity is improved.