基于预紧力齿连接的GFRP方管“梁-梁”连接节点承弯性能

BENDING PERFORMANCE OF GFRP SQUARE TUBE "BEAM-BEAM" CONNECTION JOINT UPON PRE-TIGHTENED TOOTH CONNECTION

  • 摘要: 纤维增强复合材料(FRP)拉挤型材可直接作为应急桥梁承载主梁使用,用于克服中小跨径障碍。为实现主梁纵向“梁-梁”连接,本文提出一种基于预紧力齿连接的GFRP方管连接节点(BB-PTC)。制备节点足尺试件,开展悬臂承弯试验,获得不同螺栓预紧力、千斤顶顶撑、贯穿螺栓设置工况下节点的承载性能响应、承载能力及破坏模式等。基于FRP拉挤型材双椭圆渐进损伤材料模型,编制用于显式动力分析的材料Vumat,对FRP多齿连接接头承载性能进行数值模拟,验证材料模型的网格敏感性、数值稳定性及计算精度。利用编制的渐进损伤材料模型,建立BB-PTC节点实体有限元模型,结果表明该节点模型能够准确模拟节点承弯力学响应,并准确预测节点极限承载能力及破坏模式。最后,与螺栓连接“梁-梁”节点进行对比,表明BB-PTC节点采用预紧力与齿体抗剪相结合的方式实现GFRP梁端部弯矩传递,具有较高的承载效率及连接刚度。

     

    Abstract: Fiber reinforced polymer (FRP) pultruded profiles can be directly used as emergency bridge load-bearing girders to overcome small and medium span obstacles. To realize the longitudinal 'beam-beam' connection of the girders, this study proposes a GFRP square tube connection node (BB-PTC) based on pre-tightened tooth connection. The full-scale specimens of the connection were prepared, and the cantilever bending tests were carried out to obtain the bearing performance response, bearing capacity and failure mode of the connections under different bolt preload and, jack supporting and through bolt settings. Based on the double-ellipse progressive damage material model of FRP pultruded profiles, the material Vumat for explicit dynamic analysis was compiled, and the bearing capacity of FRP multi-tooth connects was numerically simulated to verify the mesh sensitivity, numerical stability and, calculation accuracy of the material model. The finite element model of BB-PTC connection is established by using the progressive damage material model. The results show that the connection model can accurately simulate the bending mechanical response of the joint and accurately predict the ultimate bearing capacity and failure mode of the joint. Finally, compared with the bolted ' beam-beam ' joint, the BB-PTC joint realizes the bending moment transmission at the end of the GFRP beam by combining the preload with the shear resistance of the tooth body, and it has higher bearing efficiency and connection stiffness.

     

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