THE EFFECT OF USING ARC-SURFACED DAMPERS ON REDUCTION OF THE COLLAPSE PROBABILITY INDUCED BY FORWARD DIRECTIVITY

Friction Dampers having appropriate controlling properties have been utilized to mitigate the structural failure for a long time. However, since this kind of dampers have a constant slip force, they are not capable of playing an appropriate role for strong ground motion, and therefore their optimized slip force should be determined. This problem would be solved with utilization of dampers with variable slip force and it hopefully would lead to reduction of the losses induced by damages. Wang et al. (2017) have presented an innovative type of frictional damper called Arc-surfaced Frictional Damper (AFD) whose main advantage is their curved frictional surfaces that lets their damping force change with displacement. In this research, the design parameters of the arc-surfaced-induced frictional force and their influence on the performance of these dampers in reduction of the structural vibration have been investigated. Structural shape of this damper and its hysteretic behavior is shown in Figure 1. It is to be mentioned that some problems with the mathematical equations presented in Wang et al. (2017) representing the hysteresis curve of AFD have been found and a modified version is utilized in case it is needed.

Keywords:

Collapse assessment , Forward directivity , Friction damper , Variable friction force , Arc-Surfaced damper