某大跨径斜拉桥钢-混结合段PBL剪力键承载力研究

Study of Bearing Capacity of PBL Shear Connectors for Steel-Concrete Joint Section of a Long Span Cable-Stayed Bridge

基于某大跨径斜拉桥的设计,为分析其钢-混结合段PBL剪力键的承载能力,采用推出试验方法,得到PBL剪力键试件的破坏形态为钢板孔中混凝土被剪切破坏、孔中贯穿钢筋弯曲、混凝土块表面在开孔板开孔处出现横向裂缝。根据试验测试结果及PBL剪力键的传力机理、荷载~滑移规律得出PBL剪力键的极限承载力和抗剪刚度计算公式,该公式具有较高的精度。对钢-混结合段中PBL剪力键进行有限元计算分析表明:PBL剪力键在最不利设计荷载作用下,应力水平仍小于材料的允许应力。设计具有足够的强度储备。

On the basis of the design of a long span cable-stayed bridge and in order to analyze the bearing capacity of the PBL shear connectors used for the steel and concrete joint section of the bridge,the push-out test method is used to obtain the failure modes of the connectors and the failure modes obtained therefrom include the shear failure of concrete in the perforated holes in steel plate,the bending of reinforcement in the holes and the transverse cracking in concrete surface at the holes.In accordance with the test results,the force transferring mechanism of the connectors and the load^slip law,the formula having good accuracy for the ultimate bearing capacity and shear rigidity of the connectors are derived.The finite element calculation and analysis made for the connectors demonstrate that under the most unfavorable design load,the stress level of the connectors is still lower than the allowable stress of material and the design has sufficient strength reservation.