A Novel Methodology for Optimum Seismic Performance-based Design of Friction Energy Dissipation Devices

Friction-based supplemental devices have been extensively used for seismic strengthening of existing substandard structures, however, the conventional use of these dampers may not necessarily lead to an optimum structural performance. Conventionally designed friction dampers usually follow a uniform height-wise distribution pattern of slip load values mainly for simplicity of implementation. This can lead to localizing structural damage in certain storey levels, while the other storeys accommodate lower relative displacement demands. In this study, a practical performance-based optimisation methodology is developed to tackle with structural damage localization of RC frame buildings with friction energy dissipation devices under severe earthquakes. The proposed optimisation is aiming at redistributing the slip loads of the friction wall dampers so as a uniform height-wise distribution of inter-storey drifts is achieved. The efficacy of the method is evaluated through the optimum design of five different low to high-rise RC frames equipped with friction wall dampers under six real spectrum-compatible design earthquakes. The effects of different design parameters including number of storeys, convergence factor and design seismic excitations are also evaluated on the efficiency of the adopted optimisation approach. The results indicate that compared to the conventional design, using the suggested methodology to design friction wall systems can result in up to 40% reduction of maximum inter-storey drift and considerably more uniform height-wise distribution of relative displacement demands under the design earthquakes.