复杂空间桁架节点抗震性能试验研究及有限元分析

桁架转换层被广泛应用于高层建筑中，以实现结构形式的垂直转换，多榀桁架交界处的节点，其受力性能对整个桁架的安全性影响较大。结合工程实例，对上海市长宁来福士广场东部裙房桁架转换层中的两处复杂节点进行1∶4缩尺模型试验和有限元分析，研究了节点的承载力、应变发展、受力性能和破坏模式。试验结果和有限元分析表明：节点具有较高的承载力和良好的耗能能力，满足设计要求；节点腹杆板件端部的尺寸放大，改善了腹杆的轴向传力，降低了应力集中。节点的薄弱部位位于型钢混凝土柱与弦杆翼缘的交界处，节点发生破坏时，弦杆和腹杆基本没有进入屈服状态。

Experimental study and finite element analysis on seismic performance of complex spatial truss joints

The truss transfer floor is widely used in high-rise buildings with the advantage of achieving vertical transformation of structural forms. The mechanical behavior of the joint at the junction of the trusses has a significant impact on the safety of the whole truss transfer floor. To investigate the seismic performance of two complex spatial joints in the transfer floor in the Raffles eastern podium located in Changning District of Shanghai, 1/4-scale joint model tests and finite element analyses were carried out. This paper reports the test method and test results, including the strain distribution, the strain development, the capacity of the joints, and the failure mode. The test results and finite element analysis results indicate that these two joints have high load bearing capacity, good seismic performance and meet the design requirements. Local enlargement at the ends of web members improves force transfer from webs to chords, and decreases the stress concentration there.The weak area of the joints is located at the junction of the steel reinforced concrete column and the chord flanges. When the joints are broken, almost no chord and web members are in the yield state.