Proposing a New Bracing System with Bending Yielding Circular Plates under Cyclic Loading

Abstract

The most prevalent way to deal with lateral loads in steel structures is using common bracing systems like concentric bracing systems. One of the major drawbacks of this system is the buckling when the compression force exceeds the elastic buckling strength, thereby being unstable before reaching the yield limit. In other words, the behavior of these braces is asymmetric under tension/compression forces leading to reduce the ability of the system to absorption of the most exciting energy and can lead to additional structural and non-structural damages due to the change in the direction of the inertial forces. To tackle these problems and to improve the performance of bracing systems, in this work for the first time, a new bracing system called a fan bracing system has been introduced. Fan brace enhances the ductility and energy absorption of the system by removing harmful buckling effects byreplacing axial deformations with flexural ones, which tends to make the system softer and thus increase the natural vibration period of the structure and reduce the earthquake shear force. In this study, the proposed brace is studied using numerical modeling under affecting cyclic excitation based on the loading protocol of ATC-24. The advantages of this system include the symmetrical behavior even in the large cyclic deformations, as well as high energy absorption and lighter weight in comparison with the buckling-restrained brace (BRB).