Comparison of collapse-resistance capacities of RC frames with and without viscous dampers

In modern seismic design, damping devices are often used to dissipate seismic energy and therefore enable a control of the structural response to earthquake ground excitation. As a result, the member section sizes or the amount of reinforcement in a structure with dampers may be reduced from those without dampers. Although both designs may be made as equivalent in terms of their performances under design earthquakes, their capacities in resisting collapse under the worst credible earthquake scenarios could be different, and there is little information from the literature that addresses this concern. In this paper, the collapse-resistance capacities of RC frames designed for different seismic hazard levels with and without dampers are calculated through a collapse fragility analysis using an incremental dynamic analysis approach, and the results are compared. On this basis, a proposal is put forward for the purpose to enhance the collapse-resistance capacities of structures with dampers in high seismic hazard levels. The effectiveness of the proposed enhancement is demonstrated.