承压型组合剪力键剪切性能试验与承载力计算

SHEAR PERFORMANCE TEST AND BEARING CAPACITY CALCULATION OF COMPRESSIVE COMPOSITE SHEAR CONNECTOR

针对抗剪需求较大的钢-混凝土组合结构,改进了一种带横向焊钉的承压型组合剪力键。设计并开展了10个承压型组合剪力键和1个非承压型组合剪力键单调推出试验,明确了混凝土端部承压、混凝土强度、肋板厚度、肋板孔径和焊钉直径对承压型组合剪力键失效模式和破坏过程的影响。建立了承压型组合剪力键有限元模型,在结合试验验证仿真模型可靠性的基础上,进一步揭示了承压型组合剪力键受力机理。以试验变量为基础,建立并分析了108个承压型组合剪力键有限元模型,推导了承压型组合剪力键极限承载力与各参数变量之间的线性关系,对极限承载力分析结果进行多元线性回归提出了承压型组合剪力键极限承载力计算模型。结果表明:承压型组合剪力键混凝土板失效模式为大面积竖向裂缝和端部裂缝,内表面形成由焊钉高度附近向下延伸的斜主裂缝,非承压型组合剪力键混凝土板无明显端部裂缝,承压型组合剪力键极限承载力约为非承压型组合剪力键的1.4倍;与肋板孔径和焊钉直径相比,承压型组合剪力键极限承载力对混凝土强度和肋板厚度更为敏感。该研究提出的承压型组合剪力键极限承载力计算公式物理意义明确,计算值与仿真和试验结果吻合较好,可为组合剪力键设计和工程应用提供参考。

A compressive composite shear connector with transverse studs is developed for steel-concrete composite structures with high shear resistance.Ten compressive composite shear connectors and one non-compressive composite shear connector were designed,and monotonic push-out tests were carried out.The effects of concrete bearing at the end of rib plate,concrete strength,rib thickness,rib hole diameter and stud diameter on the failure mode and failure process of compressive composite shear connectors were investigated.The finite element models of compressive composite shear connectors were established.Using the simulation model verified by experiments,the shear mechanism of compressive composite shear connector was further revealed.Based on the test variables,108 finite element models of compressive composite shear connectors were established and analyzed,the linear relationship between the ultimate bearing capacity of compressive composite shear connectors and various parameter variables was deduced,the analysis results of ultimate bearing capacity were regressed,and the calculation model of ultimate bearing capacity of compressive composite shear connectors was proposed.The results show that the failure modes of concrete slabs of compressive composite shear connector are large-area vertical cracks and end cracks,and inclined main cracks extending downward from near the height of welding nails are formed on the inner surface.The concrete slabs with non-compressive composite shear connector have no obvious end cracks,and the ultimate bearing capacity of compressive composite shear connector is about 1.4 times that of the no-compressive type.Compared with the diameter of rib and stud,the ultimate bearing capacity of compressive composite shear connector is more sensitive to concrete strength and rib thickness.The proposed model of ultimate bearing capacity of compressive composite shear connector has clear physical meaning,and the calculated results are in good agreement with the simulation and test results,which can provide a reference for the design and engineering application of composite shear key.