Inelastic cyclic response of RBS connections with jumbo sections

This paper examines the cyclic performance of reduced beam section (RBS) moment connections incorporating larger member sizes than those allowed in current seismic provisions for prequalified steel connections, through experimentally validated three-dimensional nonlinear numerical assessments. Validations adopted finite element procedures are carried out against experimental results from two test series, including four full-scale RBS comprising large structural members, outside prequalification limits. After gaining confidence ability models to predict closely full inelastic response and failure modes, parametric investigations undertaken. Particular attention is given assessing influence RBS-to-column capacity ratio as well geometry location on overall response. The observations provide a detailed insight into behavior, strength, ductility, modes connections. It shown that which consider sections beyond code limits, by up times weight or depth developed stable characterized flexural yielding local buckling. However, with very sections, three-times typically prescribed exhibited significant hardening resulting severe demands at welds, hence increasing susceptibility weld fracture propagation column. findings this study point need, jumbo thick flanges, deeper cut currently specified design, about 66% total width. modification would be required promote governed extensive while reducing excessive strain beam-to-column welds. Moreover, relatively deep columns, it more stringent design requirements need followed, combined appropriate bracing RBS, avoid out-of-plane rotation.