Effect of the Height Increasing on Steel Buildings Retrofitted by Buckling Restrained Bracing Systems and TTD Damper

The behavior of conventional braced frames are not the same in tension and compression. This problem can be improved by prevention of buckling under compressive loads, which is called bucklingrestrained brace (BRB). In this field, TTD metal damper also have attracted much attention due to simplicity in construction and execution. This damper is recommended because of accessing to better performance than BRB and also having easier construction technology and consequently being cheaper thus possibility of making it becomes feasible in countries without complex technologies. In this research, three steel structures with three, five and eight stories that require retrofitting, are retrofitted using buckling restrained brace and TTD metal damper separately, and are compared before and after the retrofitting using nonlinear dynamic analysis in PERFORM 3D software. Finally, the effects of this systems in reduction of structure displacement, reduction of energy dissipation due to nonlinear behavior in main members of structure, and increasing of performance level is inspected. The observation of both systems results imply that with increasing the number of building stories, expressed positive effect is reduced which indicates more effect of this energy dissapation systems in short-order structures.