施工工艺对空间KK型圆钢管搭接节点静力性能的影响研究

Study on effect of construction process on static behavior of multiplanar overlapped CHS KK-joints

不同的施工工艺对平面内外均搭接的圆钢管(CHS)空间KK型节点的静力性能会产生影响,为确定这种影响的大小,根据内隐蔽区焊接方式及插板布置方式的差异,共完成了9个节点静力试验,其中5个试件主要考察内隐蔽焊缝焊接方式的影响(未设置插板),2个试件设置插入弦杆的纵向插板以规避平面外搭接内隐蔽区焊缝,2个试件设置纵横向插板以规避所有内隐蔽区焊缝。通过试验考察了各空间搭接节点的受力性能和破坏模式,对比了内隐蔽区是否焊接、纵向插板是否插入弦杆,以及横向插板等对节点性能的影响。结果表明,内隐蔽区是否焊接对节点的应力分布有一定影响,但对节点承载力的影响较小;不插入弦杆的纵向插板在规避平面外搭接内隐蔽区焊缝的同时使节点承载力略有提高;插入弦杆的纵向插板对节点整体性能的加强作用显著,但同时降低了节点的延性;横向插板对节点性能的影响很小。采用经试验验证的有限元模型分析了内隐蔽区是否焊接及纵向插板对具有不同几何参数的节点承载力的影响,并综合试验分析结果给出了设计此类节点的建议。

To study the static behavior of multiplanar overlapped circular hollow section （CHS） KK-joints （ muhiplanar KK-Ov joints） both in plane and out of plane with different construction process, five specimens with different welding conditions of hidden seam and four specimens with vertical stiffener for avoiding partial overlapping of one brace member onto another were tested under monotonic loading. The testing procedure, the joint＇ s mechanical performance and the failure modes were presented. The effects of various factors including the different welding conditions of hidden seam, the longitudinal stiffener through the chord or not and the transverse stiffener on the joint behavior were studied. Results of these tests show that the welding condition of hidden seam has some effects on the joint＇ s stress distribution, but the static bearing capacity of multiplanar KK-Ov joints is not affected significantly. The longitudinal stiffener cutting through the chord has remarkable strengthening effect on the joints but can cause decreased ductility. The joint＇ s static bearing capacity is slightly improved for the stiffener not cutting through the chord. The transverse stiffener almost has no effect on the joint＇ s performance. Based on the test study, nonlinear finite element modeling was developed and used to study the effects of hidden seam welding condition and longitudinal stiffener on the capacity of joints with different geometrical parameters. Design recommendations are suggested based on both experimental study and numerical analysis results.