2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Recent earthquakes have revealed that conventional seismic design can allow large levels of structural and nonstructural damage. Retrofitting buildings with fluid viscous dampers (FVDs) can improve interstorey drifts and floor accelerations: parameters that characterise seismic demands. Many damper placement methods have been proposed, however no conclusive optimal method has been identified. This paper benchmarks the seismic performance of Eurocode-compliant concentric braced frame buildings and investigates the optimal placement of FVDs. The FEMA P-58 procedure was used to assess performance in repair costs. Storeys satisfying the Eurocode drift limit for nonstructural protection nevertheless experienced drift- and acceleration-sensitive damage. Acceleration-sensitive damage was of comparable or greater consequence than drift-sensitive damage. The optimal amount of damping to minimise repair costs was identified as 30-40%, larger than previously suggested levels based on structural parameters. Six damper placement methods were evaluated using linear FVDs. Iterative methods that purport to optimise performance did not achieve that objective: local rather than global parameters are considered, and optimising for a single parameter may worsen another that impacts damage. The storey shear strain energy method and uniform damping produced repair costs more favourable than, or equal to, the other placement methods. Damper placement optimisation may be successful for high-rise or irregular structures.