波形钢-UHPC组合桥面板中栓钉-PBL连接件抗剪性能数值模拟研究

Numerical study on shear performance of stud-PBL shear connector in corrugated steel plate-UHPC layer composite deck

针对波形顶板-超高性能混凝土(Ultra-high Performance Concrete,UHPC)新型组合桥面板结构,提出在波形钢板波峰处布置短栓钉,波谷处布置开孔板(Perfobond Leiste,PBL),形成栓钉-PBL组合连接件协同抗剪。为探究该组合连接件的抗剪力学性能,建立组合连接件推出试验及梁式试验的有限元模型,并基于现有试验对模型的正确性进行验证。在此基础上,讨论了栓钉直径、PBL孔径、栓钉抗拉强度和UHPC抗压强度等设计参数对组合连接件抗剪性能的影响规律。通过分析组合连接件在推出试验全过程中的剪力分配规律,揭示了波形顶板-UHPC组合结构中栓钉与PBL剪力连接件的协同工作机理及破坏机理,并基于此提出组合连接件的设计理论和抗剪承载力计算方法。研究结果表明:组合连接件受到的剪力由栓钉和PBL共同承担,增加短栓钉直径、PBL孔径和UHPC强度均可有效提高组合连接件抗剪承载力;栓钉与无贯穿钢筋的PBL连接件抗剪承载力相近时,后者在加载初期承担的荷载较大,并会早于栓钉发生破坏;二者抗剪承载力之比在1.5左右时,大致同时进入破坏阶段,组合效果最佳;提出的栓钉-PBL组合连接件抗剪承载力计算公式的计算结果与有限元及试验结果吻合度较高;抗剪连接程度相同时,采用组合连接件的桥面板受力性能最佳,钢板与UHPC层之间的相对滑移和间隙均最小。

A combined shear connector has been proposed for the innovative composite bridge deck consisting of corrugated steel plate and UHPC(Ultra-high Performance Concrete)layer.Short studs are suggested to be fixed at the wave peak of the corrugated steel plate,while PBLs(Perfobond Leiste)are recommended to be fixed at the wave trough.Numerical models were established to investigate the shear behavior of the corrugated steel plate-UHPC interface combined shear connector.The models were verified using existing experimental results.The shear performances of the combined shear connector were analyzed,taking into account design parameters such as stud diameter,PBL hole size,stud tensile strength,and UHPC strength.This allowed for the revelation of the failure mechanism and cooperative working mechanism between the stud and PBL.The formula for calculating the shear capacity and design method of the combined shear connector was proposed.The analysis focused on the distribution of shear force in the combined shear connector during the push-out test.The results indicate that the shear force of the combined shear connector was jointly borne by the studs and PBLs.The increase in stud diameter,PBL hole size,and UHPC strength improves the shear capacity of the combined shear connector.The PBL,which does not have steel bar damages,fails earlier than the stud despite having similar shear capacities.When the ratio of shear capacities between PBL and stud is about 1.5,the PBL and stud fail around the same time,and the best combination effect is achieved.The formula for the combined shear connector’s ultimate shear capacity is highly precise,and the calculated results align well with both FEM and experimental results.The composite deck joined with combined shear connector exhibits the best mechanical performance when compared to decks with the same shear connection degrees.This is due to the fact that the relative slip and gap between the steel plate and the UHPC are minimized.