装配式钢-混凝土组合梁T型预埋螺母侵入式螺栓连接件的抗剪拔性能试验研究

EXPERIMENTAL STUDY ON SHEAR AND TENSILE BEHAVIOR OF T-SHAPED EMBEDDED-NUT BOLTED SHEAR CONNECTORS IN PREFABRICATED STEEL-CONCRETE COMPOSITE BEAMS

  • 摘要: 为研究T型预埋螺母侵入式螺栓连接件在装配式钢-混凝土组合梁中的抗剪拔性能,对4组T型预埋螺母侵入式螺栓连接钢-混凝土组合梁试件进行了抗剪推出试验,分析了螺栓等级和混凝土类型这两种参数对T型预埋螺母侵入式螺栓连接件的破坏形态、荷载-滑移特性和抗剪承载能力的影响;同时,开展T预埋螺母侵入式螺栓连接件的抗剪拔推出试验以及数值模拟,利用试验结果对仿真结果进行对比修正,验证建模方法的正确性,并利用数值模拟的结果与现有研究成果进行对比分析,探究了T型预埋螺母侵入式螺栓连接件的抗剪拔性能。试验结果表明:高强螺栓连接件的破坏模式为螺杆在钢梁和混凝土界面间的弯剪破坏、螺栓根部周围混凝土受压破坏和混凝土板开裂完全压坏。T型预埋螺母侵入式螺栓连接件抗剪承载力主要受螺栓强度和混凝土类型的影响,适当提高螺栓强度以及采用超高性能混凝土,可提高螺栓连接件的抗剪承载力。数值模拟分析得出:T型预埋螺母侵入式螺栓连接件因受到混凝土板厚以及预埋内螺母高度的限制,螺帽与内螺母之间的混凝土厚度不足,无法提供足够的抗拔力,其抗拔性能在剪拔复合作用下表现不足。

     

    Abstract: To study the shear and tensile behavior of T-shaped embedded-nut bolted shear connectors in prefabricated steel-concrete composite beams, a total of four push-out specimens were tested to investigate the failure modes, load-slip curves and the shear capacity of bolt connectors by changing parameters including tensile strength of bolt and type of concrete. Shear and tensile push-out test and finite element numerical simulation analysis were carried out to ensure the correctness of the modeling method by comparing test results and numerical results. Numerical results were obtained to investigate the shear and tensile behavior of T-shaped embedded-nut bolted shear connectors through a comparison with existing research results. The push-out test results show that: the damage mode of high-strength bolts is the bending shear damage of bolt at the interface between the steel beam and concrete, the concrete around the root of the bolt is damaged by compression and the concrete plate is cracked and completely crushed. The shear behavior is mainly affected by the tensile strength of the bolt and the type of concrete, and the shear bearing capacity of bolted joints can be improved by increasing the strength of the bolt and adopting UHPC. Numerical analysis shows that: T-shaped embedded-nut bolted shear connectors are limited by the thickness of the concrete slab and the height of the inner nut, the concrete thickness between the nut and the inner nut is insufficient to provide sufficient pullout force, and its tensile behavior is insufficient under shear and tensile composite forces.

     

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