Applications of hysteretic steel dampers for controlling the seismic damage in steel frames

The aim of seismic design is not intended to make earthquake-proof structures that will not experience any damage even during a strong earthquake; such structures will be too costly. However, controlling the damage to the desired level is a necessity for buildings with a particular purpose such as hospital, fire and police station, nuclear facilities, buildings that contain hazardous material, and other building that is critical for emergencies and defense. In this paper, a four-story steel frame, both with and without hysteretic steel damper are investigated in order to account the effect of stiffness ratio, and SR (ratio between steel damper and braces stiffness to the bare frame stiffness) in the global structural damage. For these purposes, three ground motions which are compatible to the design spectrum response in the Indonesian building code were selected to be applied to the structure with a stiffness ratio (SR) of 2, 3, 4 and 5 using a non-linear dynamic time history analysis. In this context, the damage index based on the works of Park and Ang is used as the criteria to define global structural damage, while story drift index is used as the criteria to measure the seismic performance level. The results demonstrated that the use of steel damper not only enhances the seismic performance, but it also reduces the damage index of the investigated structure. Furthermore, the damage index and story drift index are influenced by the stiffness ratio, in which the stiffness ratio of 4 (four) provides the smallest damage index and inter-story drift index. Moreover, the damage index and inter-story drift index were also affected by ground motions characteristics. (paper)