Ring-Shaped Lateral Bracing System for Steel Structures

Abstract

Buckling of compression members has a great impact on the reduction of energy dissipation capacity and ductility of the structural system such as concentrically braced frame systems (CBFs). As well, direct connection of tensile and compression members to beams and designation of the link beam as a fuse, and the formation of plastic hinges in the link beam in eccentrically braced systems (EBFs) endanger the safety of this type structural systems. This paper introduces a new ring-shaped lateral bracing system so-called the Shami lateral bracing system (SLBs) which removes the common tensile and compressive members along with their connections to the structure. As a substitute, SLBs introduces a new element with proper ductility and energy dissipation capacity and could be an appropriate alternative to the existing systems. Because of the high degree of statically indeterminacy of the proposed system, the structural stiffness does not lead to a steep reduction after the formation of the first plastic hinge. The performance of this lateral system is evaluated by numerical modeling, and the results show that the structures resist against the lateral loads with acceptable seismic performance. It seems that this system in comparison with CBF and EBF systems may not be cost-effective for bending of the ring, welding, etc., but from the seismic performance points of view, it has good performance.