Development of Next Generation Adaptive Seismic Protection Systems
Conventionally designed structural frame systems develop significant inelastic deformations under strong earthquakes, leading to inelastic hysteretic behavior, stiffness and strength degradation, increased interstory drifts, and damage with residual drift. Passive seismic protection systems in the form of supplemental damping devices have emerged as an effective approach for reducing response and limiting damage by shifting the inelastic energy dissipation from the framing system to the dampers. However, such dampers do not generally provide self-centering stiffness capability or counter stiffness degradation.
Recent investigations have shown that a combination of adaptive stiffness and damping (ASD) devices can provide substantial response modification, particularly during near-fault pulse-type earthquakes. The research vision of this project is to develop the next generation of seismic protection systems by combining a new class of self-centering adaptive stiffness systems with highly efficient energy dissipation. The goal is to mimic the behavior of actively controlled devices by developing self-contained semi-active ASD devices with feedback and passive ASD devices with internal hydraulic feedback.
The project is expected to advance the state-of-the-art of increased resilience through structural response modification, contributing to earthquake hazard mitigation and expedient post earthquake recovery (due to easy replacement of ASD systems). The project will broadly impact earthquake engineering practice through educational outreach and wide dissemination of research findings through the project web site.
Nagarajaiah S. "Adaptive passive, semiactive, smart tuned mass dampers: identification and control using empirical mode decomposition, hilbert transform, and short-term fourier transform," Structural Control and Health Monitoring, v.16 (7-8, 2009, p. 800).