Elastic drift amplification factor in steel moment frames with double reduced beam section (DRBS) connections

Abstract

The recently proposed double reduced beam section (DRBS) connection is a steel moment connection intended to delay buckling failure modes and achieve a more ductile seismic behavior . This design adds an extra reduced section to the prequalified radius-cut reduced beam section (RBS) connection and aims to shift the plastic hinge further away from the beam-column interface. In this study, to investigate the effect of the DRBS connection on the stiffness of the steel moment frames, first, while presenting a theoretical approach based on geometric relationships and utilizing the method of virtual work, the exact formulae for calculating the elastic drift and the elastic drift amplification factor in a steel moment frame with DRBS connections were developed. Next, by conducting a sensitivity analysis, the DRBS connection parameters with the most significant effect on the elastic drift of the considered frame were determined. The accuracy of the proposed exact theoretical formulae and the conducted sensitivity analysis was confirmed through finite element modeling . The response surface method (RSM) was then utilized to derive highly accurate and specific relationships for the elastic drift amplification factor in frames made of the different HEA and IPE sections considered. Ultimately, two accurate and simple formulae based on the DRBS connection parameters were presented for estimating the elastic drift amplification factor in steel moment frames with DRBS connections constructed of HEA and IPE sections. The results indicated that utilizing DRBS connections could increase the elastic drift up to 14.7% and 5.5% in steel moment frames built with HEA and IPE sections, respectively. • Investigation the effect of the DRBS connection on the stiffness of the steel moment frames. • Conducting a sensitivity analysis on different parameters of DRBS connection effective on the elastic drift. • Finding the most important effective parameters on elastic drift of steel moment frames with DRBS connections. • Presenting two formulae for estimating the elastic drift amplification factor in the frames with DRBS connections.