Gusset design considering buckling forces in frame and brace action directions: Test and finite element analysis of a self-centering braced frame for verification

A steel dual-core self-centering brace (DC-SCB) has been developed to combine both energy dissipation and self-centering properties into a single member for seismic resistance. A strong gusset-weak brace design assures the seismic response of the DC-SCB in earthquakes. In this work, in-plane cyclic tests and finite element analyses were conducted on single story steel frames with the DC-SCB to investigate the performance of corner gusset plates due to the brace axial force (which acts in the direction of the brace) combined with the force from the frame action (which acts in a direction near perpendicular to the brace axial force). Different configurations of gusset plates were used for analyses to develop a design method to consider effects from brace forces and frame action forces. The yielding and buckling forces of a gusset plate in the frame action direction are verified based on a proposed column strip model and buckling coefficient varied with gusset thickness. It is shown to be consistent with the behavior from the tests and finite element analyses with errors in strength of up to 13% for the range of gusset configurations considered.