Using bracing systems to improve the seismic performance of moment resisting frame

Abstract

Bracing systems [BS] have been widely adopted as the primary lateral load resisting system in medium and high-rise buildings due to their inherent substantial lateral stiffness and load resistance, and it is considered the most effective method for fusing existing RC structures. Therefore, the seismic response of steel braced frames [SBF] with bracing members connected to the columns had been explored for a moment-resisting frame [MRF]. And different configurations of BS had been investigated to study their effects on lateral load resistance and get the optimized bracing configurations. Moreover, the study doesn’t take into consideration only the BS over the height of the building, but it also reduces the length of the bracing element by adding many bracing panels over the height of stories which can lead to an increase in the resistance of seismic loading. The bracing panels can be an effective technique in dealing with the architects' constraints. Therefore, smaller brace components can be chosen for studying to avoid the architect’s constraints and create different configurations while still meeting code criteria for brace strength and overall slenderness. The earthquake behavior of the retrofitted structure was analyzed by distributing the SB of various types (X, V inverted) over the height of the RC frame. The results demonstrate that the smaller brace components for X & V inverted bracing can contribute to reducing the lateral displacement and maximum story drift.

Keywords

• bracing models
• response spectrum
• retrofitting
• mrf