损伤可控型钢框架边节点的试验研究

Experimental study on exterior joint of damage control steel frame

  • 摘要: 该文提出一种损伤可控型钢框架节点(DCSF节点)。在梁端腹板上设置连接钢板,通过高强摩擦螺栓将梁、柱拼接在一起,并在梁内布置预应力筋来提供节点的复位能力。在小震作用下,通过高强螺栓来提供节点的初始刚度和抗弯承载力;在中震作用下,通过螺栓杆在螺栓孔壁内的滑移来改善节点的耗能,以此避免梁、柱主体构件受到损伤。共设计完成了4个足尺试件的低周往复加载试验,分别考虑了连接钢板的不同接触表面、预应力筋的初张拉值以及高强螺栓预紧力对该类节点的初始刚度、损伤特征、滞回性能和自复位能力的影响。研究结果表明:高强螺栓在螺栓孔内的滑移为节点提供了良好的耗能能力;预应力筋能够减少结构的残余变形,提供节点的自复位能力;当层间位移角达2.4%时,主体构件未发现明显损伤,螺栓杆与孔壁发生挤压破坏,更换连接钢板后,节点的承载力和耗能能力基本不变,DCSF节点具有良好的抗震性能;节点的连接无需现场施焊,施工方便、快捷,可在地震区推广应用。

     

    Abstract: This paper presents a damage control steel-frame-joint (DCSF joint). By setting a splice plate on the web of a beam end, a beam and a column are connected by high strength friction bolts, and the prestressed reinforcement in the beam can provide re-centering capacity for the joint. Under a small earthquake, high strength friction bolts provide the initial stiffness and flexural bearing capacity for the joint; under a medium earthquake, and the slip of a bolt rod in a bolt hole dissipates energy for the joint. Therefore, main structural members are protected from damage. In order to study the initial stiffness, damage characteristics, hysteretic behavior and re-centering capacity of the joint, four full-size specimens were designed and tested under cyclic loading. Considering the effects of different contact surfaces of splice plates, the pretension of prestressed reinforcement, and pre-tightening force of high strength bolts respectively, the experimental study shows that:the slip of a high strength bolt rod in a bolt hole can provide good energy dissipation ability for the joint; the prestressed reinforcement can reduce the residual deformation of the structure and provide re-centering capacity for the joint; when inter-story displacement angle reaches 2.4%, the damage was mainly concentrated in bolt rods and the extrusion area of bolt holes on a splice plate, no obvious damage was found in main structural members. The bearing capacity and energy dissipation capacity of the joint basically remains unchanged after replacing the splice plate. The results of the study show that DCSF joint can be popularized and applied in earthquake regions due to its good seismic performance and convenient construction process without site welding.

     

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