Enhancement of ductility of steel moment connections with noncompact beam web

A simple method of welding longitudinal stiffeners (LSs) in the beam web within plastic energy dissipation zone is proposed here to enhance the ductility of beam-to-column connections with noncompact beam web. In this study, a series of cyclic loading experiments on full-scale beam-to-column subassemblies demonstrating weak-beam-strong-panel characteristics, designed using the proposed connection method, were conducted to examine their seismic resistance characteristics. Attention was mainly focused on the ductility and energy dissipation capacity of beams itself. Test results show that the presence of the LSs is effective in deferring the local buckling of the beam web. The proposed connection method is preferred to enhance ductility of steel moment connections with noncompact beam web in terms of both economic efficiency and fabrication convenience. Parametric studies through simplified finite element models verified by tests were furthermore carried out to clarify the effects of main parameters on the ductility enhancement of steel moment connections. With the increase in the flexural rigidity ratio of the LSs to beam web, the ductility is found to be improved. It is also found that the minimum required flexural rigidity recommended by AASHTO can guarantee good ductility for stiffened connections with the slenderness ratio of beam web less than 130 when sustaining cyclic bending.

► Effect of longitudinal stiffeners on connection ductility was experimentally studied.
► The flexural rigidity ratio has a significant influence on the connection ductility.
► The minimum required flexural rigidity ratio was obtained in terms of ductility.