Experimental and numerical investigation of ductile top-flange beam splices for improved buckling-restrained braced frame behavior

Buckling-restrained braced frame performance at high drifts is improved by providing beam splices that reduce demands in the gusset regions. Existing experimental data only consider web splices without a slab present. An alternative top-flange splice, proposed by others, was investigated experimentally and numerically. Two full-scale top-flange beam splices from a prototype frame were tested using the qualifying buckling-restrained brace frame cyclic loading protocol. During experimental testing, the gusset connection regions remained essentially undamaged through multiple cycles at 0.06rad drift. The splice plates experienced low inelastic strains but fatigue analyses indicate they could withstand over fourteen similar loading histories without requiring replacement. Finite element models were used to investigate the influence of slabs on connections with web splices or top-flange splices. When slabs were considered, the top-flange splice transmitted over seventy-percent less moment than the web splice.