PITA Fiscal Year 2010 Projects - Innovative Infrastructure Systems

Performance-Based Design For Cost-Effective Seismic Hazard Mitigation In Buildings Using Supplemental Passive Damper Systems

Principal Investigators: James Ricles, Co-PI: Richard Sause

The proposed study will develop and validate a multi-level, probabilistic, performance-based seismic design procedure for buildings with supplemental passive damping systems. In this procedure, the design of the damping system is integrated with the design of the associated seismic load resisting frames, and the uncertainties that influence the level of damage caused by ground motions at different seismic hazard (input) levels are treated explicitly.

The project will design two steel-framed prototype buildings as the context for the research. For the proposed study, large-scale elastomeric dampers will be placed in the structure. Analytical and experimental studies will be conducted on the building. Characterization tests will first be performed to enable models of the damper to be developed. These models will subsequently be used in the analytical studies. The analytical studies will involve nonlinear time history analysis of the buildings, with the results used to generate fragility curves for prescribed response quantities. The fragility curves will establish the probability of limit states occurring that will in turn enable an assessment of the whether design objectives have been achieved. The experimental studies will provide an experimental validation of the design procedure. The experimental studies will utilize state-of-the-art procedures, and involve the use of the real-time hybrid simulation method to impose seismic loading on a scale model of the lateral load resisting system for the building.

The project builds upon results from prior studies on elastomeric dampers, where a first-generation damper was constructed and mechanical properties for the damper were obtained. These studies helped to establish real-time hybrid simulation methods for structural systems with passive dampers, which led to preliminary assessment of these dampers for vibration control under seismic loading.