为了解钢-UHPC组合梁中长栓钉连接件的抗剪承载力和钢-UHPC界面滑移特性,采用推出试验和有限元法进行研究.设计、制作13个采用不同长栓钉布置形式的钢-UHPC试件进行推出试验,同时建立采用不同长栓钉与UHPC接触关系(面面接触、绑定约束、内置区域)的推出试件有限元模型,分析试件的长栓钉抗剪承载力、界面滑移性能,拟合得到考虑UHPC增强系数的钢-UHPC组合梁的长栓钉抗剪承载力、荷载~滑移公式,并与国内外规范、相关研究公式及试验值进行对比.结果表明:钢-UHPC推出试件破坏模式均为长栓钉剪断;采用面面接触的有限元模型荷载~滑移曲线与试验结果较为接近,而采用绑定约束和内置区域的模型中长栓钉受力行为与实际不符,计算值与试验值误差较大;现有规范及相关研究中的栓钉抗剪承载力、荷载~滑移公式计算值与试验值误差较大,本文公式计算值与试验值吻合较好,可用于长栓钉连接件钢-UHPC组合梁抗剪性能的初步确定.
This study focuses on the shear capacity of long stud connectors as well as the steel-UHPC interface slip characteristics in the steel-UHPC composite beam.13 steel-UHPC specimens with different arrangements of long stud connectors are prepared for push-out test.Specimens with different long stud connectors and UHPC contacting patterns(including surface-to-surface contact,tie constrain,and embedded region constrain)were numerically simulated to analyze the shear capacity of long stud connectors,interface slip responses of the specimens,and based on which,the formulas to calculate the shear capacity and load-slip responses of the long stud connectors in the steel-UHPC composite beam that take into account the UHPC enhancement factor were fitted.The calculations were compared with the data obtained by using the formulas suggested in the domestic and overseas specifications,equations proposed in relevant researches and test data.The results demonstrate that in the push-out test,all the steel-UHPC specimens exhibited sheared long stud connectors.In the surface-to-surface contact,the simulated load-slip responses approximate the test results,while in both the tie and embedded region constrain,the simulated load bearing behaviors of studs do not agree with the actual conditions,showing big bias.The load bearing capacity and load-slip responses calculated by using the formulas suggested in the codes and related researches are also not in alignment with the test results.However,the load bearing capacity and load-slip responses calculated by the proposed formulas agree well with the test results,which can be used to preliminarily determine the shear capacity of the long stud connectors in the steel-UHPC composite beam.