The Role of the Joint Panel Shear Deformation in Beam-to-Column Connections Part 1: Results of the Experimental Test Program

Abstract

This research was performed to develop a deeper understanding in the effects of joint panel shear deformation on elasto-plastic behavior of the beam-to-column connections. Fourteen full-scale beam-to-column subassemblies were experimentally tested under cyclic loading and results are reported. Main parameters in this investigation were the joint panel strength ratio, weld joint detail, material toughness and column flange width to thickness ratio. It is shown that 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 was 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.

The Role of the Joint Panel Shear Deformation in Beam-to-Column Connections Part 2: Numerical Analysis on Stress and Strain of Hot Spots

“…In balanced and strong panel specimens, root of the weld access hole (SC) gives higher crack index compared to other hot spots and different weld joint details of S-type and F-type had no effect on cracking from this critical hot spot. Experimental test observations reported in part 1 of the paper 7) also confirmed the high potentiality of cracking at root of the weld access hole (SC) with no effect of weld joint detail. It was observed that in all specimens regardless of weld joint detail first crack initiation was occurred at root of weld access hole (SC) and the basic failure mode in all specimens was crack propagation from this hot spot.…”

“…In here, detail observations of failure of test specimens, reported in Part 1 of the paper 7) are newly discussed to show the detailed information of damages at hot spots. Table 1 presents the specification of specimens.…”

“…Specimens designed with two types of weld joint details of field (F-type) and shop (S-type) welded joint details as illustrated in Figure 2. More description regarding the specification of specimens can be found in 2.1 of Part 1 of the paper 7) .…”

“…In these graphs the horizontal axis is beam component rotation (θ b ) normalized to beam plastic rotation capacity (θ bp ) and the vertical axis is beam moment at column face (M) normalized to beam full plastic capacity ( b M bp ). A graphical illustration for the beam component rotation is presented in Figure 4 of Part 1 of the paper 7) . For both specimens regardless of joint panel strength ratio, acceptable correspondence between numerical analyses and experimental test results can be observed.…”

“…This numerical analysis is a part of research program which was conducted aiming to improve the understanding of joint panel plastification behavior and its effects on elasto-plastic behavior of steel moment connections. This study focused on understanding the effects of joint panel strength ratio on crack initiation at hot spots which was done following the observation of damages in series of experimental tests which were reported in Part 1 of the paper 7) . For sake of simplicity in the modeling, the effect of HAZ on cracking was not considered in this study.…”