A new energy-dissipating RBS connection with double-nut-bolts: Seismic performance assessment and design methodology

Abstract

This article investigates analytically the seismic performance of a new RBS beam-column connection system with Double Nut Bolts (RBS-DNB) and double shear tabs. The bolts in the proposed RBS-DNB connection are used to: i) increase the strength of the beam’s reduced section, ii) increase the energy dissipating capacity of the connection, and iii) delay damage of the beam in the plastic hinge zone. A reference RBS connection from the literature is first modeled and calibrated in Abaqus® software. A set of RBS-DNB connections are then designed (according to a new proposed method) and subsequently modeled in Abaqus®. The analytical results from the reference RBS connection and RBS-DNB connections are then compared in terms of cyclic response, beam strength, dissipated energy, beam hinge deformation and damage. The results show that, compared to the reference RBS connection, the proposed RBS-DNB connection system can increase the strength of the beam’s reduced section and dissipate more energy by up to 16 % and 12 %, respectively. Moreover, a damage assessment shows that RBS-DNB connections can efficiently delay the initiation of beam hinging, and reduce buckling deformation and damage to the beam hinge compared to the reference RBS connection. The new proposed design method ensured the safe load-carrying mechanism of RBS-DNB connections, and it also predicted well the potential damage at the components of the RBS-DNB connections. Finally, the results of pushover analyses on typical 4-storey buildings with RBS-DNB connections demonstrated their higher lateral load bearing capacity compared to those with conventional RBS connections. This study contributes towards developing more robust energy-dissipating connections for steel buildings located in seismic areas.