Finite element simulations of unequal-depth panel zones in steel beam-to-tubular column joints

This study evaluates the cyclic behavior and shear capacity of the unequal-depth panel zones in steel I beam-to-tubular column joints. Seven specimens are tested under the cyclic loadings, and tri-dimensional finite element models are built and validated by comparing with the experimental results of seven connection specimens. The failure modes and hysteresis behavior of the unequal-depth panel zones are evaluated by the parametrical analysis including seven parameters: axial force ratio (n), beam depth ratio (D-b2/D-b1), column depth-to-thickness ratio (D/t), beam flange to column depth ratio (B-f/D), aspect ratio of the panel zone (H/D), height-to-thickness ratio of the beam web (h(w)/t(w)), and width-to-thickness ratio of the beam flange (B-f/t(f)). Two types of failure modes in panel zones were found in accordance with the buckling modes. A design method based on one-side column-to-beam strength ratio (R-ocb) is proposed, which plays a key role to control the failure modes. Additionally, the design formula for calculating the yielding strength of the unequal-depth panel zone is developed and compared with that of the experimental and numerical results with reasonable agreements. (C) 2019 Elsevier Ltd. All rights reserved.