Seismic response on T-head square-neck one-side bolted endplate connection of beam to square tubular column

Totally four T-head square-neck one-side bolted connections (TSOBCs) for H-beam to hollow section steel column (HSSC) and a standard double-sides bolted connection (SDBC) for comparison were tested under cyclic load to evaluate the seismic performance of TSOBC. Two arrangement patterns of the slotted bolt holes and two strengthening measures for the connections were studied in the tests, especially the comparison between the TSOBCs and the SDBC. The test results show that the failure mode of the TSOBCs is the same as that of the SDBC, which is endplate fracture. The TSOBC with Type-V bolt holes has higher rigidity, bending moment capacity, and energy dissipation capacity than the TSOBC with Type-H bolt holes. Overall, the TSOBCs have no less than 85% of the bending moment capacity and more than 130% of the ductility coefficient, and 145% of the energy dissipation capacity of the SDBC in whole cycle life, which indicates that TSOBC can replace SDBC under certain conditions. Moreover, the strengthening measures of endplate stiffener and concrete filled in the HSSC can significantly improve the yield bending moment of TSOBC by 13.2% and 50.8%, respectively, but the latter will weaken the ductility coefficient of the joint by 35.2%. Test results on the bending moment capacity and failure mode of TSOBC under static and cyclic loads agreed well with calculated results by currently available computational models.

Automated summary

The seismic performance of T-head square-neck one-side bolted connections (TSOBCs) was evaluated in comparison to a standard double-sides bolted connection (SDBC) under cyclic load testing. Results showed that TSOBCs have higher rigidity, bending moment capacity, and energy dissipation capacity than SDBC. Strengthening measures such as endplate stiffener and concrete filling can significantly improve the performance of TSOBC, but may also affect the ductility coefficient of the joint.