Joint panel in steel moment connections, Part 1: Experimental tests results

Abstract

This paper presents results of experimental tests performed to develop a deeper understanding in the effects of joint panel shear deformation on elastic plastic behavior of the beam-to-column connections. Fourteen full-scale beam-to-column sub-assemblies were experimentally tested under cyclic loading and results of careful global and detail observations are reported. Main parameters in this investigation were joint panel strength ratio, weld joint detail, material toughness and column flange width-to-thickness ratio. It is shown that in all specimens regardless of joint panel strength ratio and weld joint detail, first crack initiation was observed at root of the weld access hole. This occurred at earlier stage with higher progress for strong and balanced panel specimens compared to weak panels. The progress of this crack was governed by beam component rotation for all specimens, and specimens with higher material toughness could sustain higher crack opening before final failure. For each series of specimens with same failure mode of beam fracture, beam cumulative plastic rotation capacity was not strongly affected by joint panel strength ratio. Experimental test results revealed that the total cumulative plastic rotation capacity is increased by reduction of joint panel strength ratio. Even weak panel specimens with heavy flange column section, could show high amount of cumulative total plastic rotation capacity at a level comparable to other weak panel specimens.