Compressive behavior of dual-gusset-plate connections for buckling-restrained braced frames

This work conducts compression tests and finite element analyses for steel dual-gusset-plate connections used for buckling-restrained braced frames (BRBFs). Compared to a single-gusset-plate connection, dual gusset plates sandwiching a BRB core reduce gusset plate size, eliminate the need for splice plates, and enhance connection stability under compression. The experimental program investigated ultimate compression load by testing ten large dual-gusset-plate connections. Out-of-plane deformation of the gusset plate in the test resembled that of a buckled gusset plate with low bending rigidity provided by the BRB end. The general-purpose nonlinear finite element analysis program ABAQUS was applied for correlation analysis. A parametric study of the dual-gusset-plate connection was performed to study the effects of plate size, presence of centerline stiffeners, and beam and column boundaries on ultimate compression load. The ultimate compression load of the dual-gusset-plate connection could not be predicted based on the AISC-LRFD approach due to beam flange out-of-plane deformation. The ultimate compression load of the dual-gusset-plate connection was reasonably predicted using a column strip length from the Whitmore section to the workpoint of the beam and column centerlines and a buckling coefficient of K = 2.