NUMERICAL EVALUATION OF HYSTERETIC BEHAVIOR OF BUCKLING RESTRAINED BRACES TO BE MANUFACTURED IN IRAN

Braced frames, as passive control systems of frame structures, are very efficient in controlling lateral deformation of buildings. Because of economic reasons, due to the transient nature of earthquakes, structures cannot be designed to behave in an elastic manner under seismic loads. They are therefore allowed to undergo inelastic deformations in specific points of the structure. In regular braced frames the weak link is commonly the brace element which is in compression. The main idea of Buckling Restrained Braces (BRB) is to eliminate this weak link, by preventing buckling, and having the brace behave in a similar fashion both in tension and compression. This is achieved by jacketing a core of a steel plate with concrete, which is in turn encased in a steel tube. The concrete and steel jacket are so designed as to practically eliminate the buckling of the core plate. A coating material is used between the concrete and the core plate in order to prevent transmission of axial force after the onset of plastic deformations in the plate. The purpose of the present paper, following a review of previous investigations, is to evaluate the behavior of this kind of brace under cyclic loading.