Research on Shear Capacity of Long Stud Connectors for Steel-UHPC Composite Beams

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. © 2023 Wuhan Bridge Research Institute. All rights reserved.