Optimum energy based seismic design of friction dampers in RC structures

Friction-based dampers are considered as one of the most efficient Energy Dissipation Devices (EDDs) due to their advantages such as adjustability and high energy dissipation capacity. However, their efficiency is strongly associated with the design slip load values along the structure. Conventional design methods using uniform slip load distributions may result in concentrating and localizing damage in certain storey levels. In this study, a practical energy-based optimization methodology is developed for seismic design of RC frame buildings with friction-based EDDs. The proposed method aims at improving the seismic performance of the structure by redistributing the slip loads of friction dampers to obtain a more uniform height-wise distribution of energy dissipation capacity. This leads to a design solution with maximum energy dissipation, and therefore minimum structural damage under a design earthquake. The low computational cost and efficiency of the proposed method is demonstrated through the optimum design of 3, 5, 10, 15 and 20-storey RC frames equipped with wall-type friction dampers under a set of synthetic spectrum-compatible earthquakes. The results show that after only a few steps the optimum design frames exhibit up to 31% and 70% less maximum inter-storey drift and global damage, respectively, compared to their conventionally designed counterparts.