T-Resisting Frame concept: Headway towards seismic performance improvement of steel frames

• We propose and introduce an innovative lateral resistant system of T-Resisting Frame (TRF).
• We present a step-by-step design procedure for this system.
• We numerically investigate the seismic performance of this system.
• TRF has high initial stiffness, high ductility and energy dissipation capacity.
• TRF shows stable hysteretic behavior under numerous cycles of lateral loading.

An innovative lateral resistant system, proposed as T-Resisting Frame (TRF), is introduced and discussed. It is made up of two structural parts, T-part as the main component and the secondary part of side columns. In steel structures, T-part is composed of a Vertical Plate Girder (VPG) and a pair of Horizontal Plate Girders (HPGs) to provide significant lateral stiffness and high energy dissipation capability under severe earthquakes. TRF dissipates energy predominantly through stable shear yielding of the web shear panels of HPGs. Also, side columns in TRF like columns in conventional braced frames withstand compression or tension to resist the overturning moments. An additional advantage of TRF over common bracing systems is the greater architectural freedom that provides larger openings in the frame needed for doors and windows. Using a hypothetical example of a five-story building, this paper presents a step-by-step design procedure for TRF system followed by results obtained from nonlinear finite element analyses carried out to numerically investigate the seismic performance of this newly proposed system. In addition, a series of analyses are conducted to study the effect of web stiffeners spacing of the T-part on the seismic behavior of the proposed lateral resistant system. The results demonstrate that TRF has high initial stiffness, high ductility, excellent energy dissipation capacity, and stable hysteretic behavior at large inelastic deformations under numerous cycles of loading. It is ascertained that the proposed design procedure is very effective and convenient to use for achieving the best seismic response of the TRF system.