New generation of bolted bracket connections: Safe load-carrying capacity and structural damage assessment

Abstract

Double shear bolted bracket connections (DSBBs) have been introduced in 2020 as reliable, cost-efficient, fully restrained connections. The double shear performance of bolts allows efficient reduction of bolt material usage in these types of connections. This advantage also shortens the time of bolt installation in steel moment frames. The design methodology and global hysteresis response of the DSBB connections were already presented in the scientific literature. However, the present study discusses the material damage by investigating the precise stress state of DSBB segments, connection stiffness evaluation, and energy dissipation distribution around the connection. Indeed, efficiency of the design guidelines and DSBB geometrical shape is thoroughly evaluated with the help of parametric studies of this discourse. Thus, the damage investigation of the main and parametric DSBB connections is developed by monitoring the prevalent damage indices. These damage indicators are plastic equivalent strain, rupture index, longitudinal plastic strain in bolts, undesirable out-of-plane deformations, buckling deformations, and prying action. In order to validate the results of this study, Kaiser Bolted Bracket (KBB) connection as a code-prequalified connection is selected in these comparative studies. In addition to the acceptable structural performance, DSBBs have more efficient and safer performance than or at least equivalent to the code-prequalified KBB connections.