可拆卸组合梁剪力连接件抗剪性能数值分析

Numerical Analysis on Shear Behavior of Shear Connector for Demountable Composite Beam

为避免传统螺栓剪力连接方式的缺陷,提出了一种用于可拆卸组合梁的新型插块式螺栓剪力连接件。以螺栓直径、缩颈杆段长度、插块材料和插块尺寸为研究参数,共设计了9个静力推出试件,研究了插块式螺栓剪力连接件的抗剪性能。以推出试件为原型,建立ABAQUS有限元分析模型进行数值分析,并通过试验进行验证。结果表明:插块式螺栓剪力连接件的荷载-滑移曲线呈现出预期的明显二次刚度特性,具有良好的剪切滑移延性;破坏模式为预设的缩颈杆段区段内的螺栓发生剪断,而此时预制混凝土板和钢梁无明显损伤;增大螺栓直径可以显著提高连接件的抗剪承载力和抗剪刚度;增加缩颈杆段长度可以提高连接件延性变形能力,但会降低连接件屈服抗剪承载力和抗剪刚度,对极限抗剪承载力则无显著影响;相比于普通混凝土和高强砂浆,使用超高性能混凝土作为插块材料使得插块式螺栓剪力连接件的抗剪承载力和抗剪刚度均得到了提高;插块尺寸对连接件力学性能没有明显影响,但螺栓缩颈杆段和混凝土板预留孔孔壁之间应确保螺栓有足够的剪切滑移变形空间。

In order to avoid the drawbacks of the solutions with conventional bolted shear connection,a novel plug-type bolted shear connector(PTBSC)was proposed for demountable composite beam.Nine static push-out specimens were designed with the parameters including the bolt diameter,the length of neckdown rod,the material and the size of plug,and the shear behavior of plug-type bolted shear connector was studied.Based on the prototype push-out specimen,ABAQUS finite element analysis model was established for numerical analysis,and it was verified by experiment.The results shows that the load-slip curves of the PTBSC exhibits obvious secondary stiffness as expected,and has good shear slip ductility.The failure mode is shear fracture occurred in the preset neckdown zone,meanwhile no significant damage is found on the precast concrete slab and the steel beam.The increasing of bolt diameter can significantly increase both the shear capacity and the shear stiffness of connector.The increasing of length of neckdown zone can improve the ductility of connector,but reduces the yielded shear capacity and shear stiffness,while has no obvious effect on the ultimate shear capacity.Compared with normal concrete and high strength mortar,the UHPC is the favorable material to make plugs to achieve better shear performances of the bolted connectors.The size of the plug has no obvious effect on the shear behavior of the PTBSC,but the space between neckdown zone and slab pocket should be ensured to accommodate the bolt deformation.