Mechanical behaviour of high strength steel T-stubs at elevated temperatures: Experimental study

Abstract

At elevated temperatures, an experimental study on 28 high strength steel (HSS) T-stubs specimens was carried out by tensile tests, to reveal the mechanical performance of HSS T-stubs. The mechanical property and failure mode of each HSS T-stub specimen is obtained from the tensile tests. Further, the applicability of Eurocode 3 Part 1–8 both at ambient and elevated temperatures is verified with experimental results of HSS T-stubs. The experimental study includes 28 HSS T-stub specimens varying in flange strength, flange thickness, bolt strength, bolt diameter, bolt location, and temperature, to explore the effects of various influencing factors on the mechanical properties of HSS T-stubs. Compared with the deformation of the ambient-temperature experiments, the plasticity of the flange is not fully developed and the flexural deformation of the flange is small at elevated temperatures. When the bearing capacity of the flange is slightly lower than that of other components, the experimental results indicate that the predictions of Eurocode 3 Part 1–8 on failure modes are applicable for HSS T-stubs at elevated temperatures, while its theoretical predictions on the HSS T-stubs with large d (the distance between the bolt centre and the fillet weld) are inaccurate at ambient temperature. When e/d (e is the distance from the flange edge to the bolt centre) is less than 1, the initial stiffness and tensile load-bearing capacity will be significantly reduced by increasing d, because the increasing d will significantly improve flexural deformation and reduce flexural stiffness of the flange. Moreover, the initial stiffness of HSS T-stubs is overestimated by Eurocode 3 Part 1–8 both at ambient and elevated temperatures, especially the T-stubs with thick flanges, while the tensile load-bearing capacity of HSS T-stubs is conservatively predicted.