Exploration of Negative Stiffness Devices for Seismic Resilience and Hazard Mitigation
Alex Lim
School of Engineering
Faculty Supervisor: Cheng Chen
Negative stiffness devices (NSDs) have emerged as a promising strategy for enhancing the seismic performance of structures within the field of civil engineering. Conventional seismic design is primarily ductility-based, permitting controlled inelastic deformation to dissipate seismic energy and prevent catastrophic collapse during strong ground motions. Ductility-based designs are effective in achieving life-safety objectives but often result in structural damage, residual deformations, and associated economic losses. NSDs provide an alternative seismic mitigation strategy by modifying the dynamic characteristics of a structure rather than relying solely on material yielding for energy dissipation. By introducing negative stiffness to the structure at predetermined thresholds, NSDs reduce the effective lateral stiffness and elongate the natural period of the system. This shift in dynamic properties can reduce spectral acceleration and seismic force demands. When integrated with supplemental damping devices such as viscous dampers, NSDs enable simultaneous control of displacement and acceleration responses to enhance seismic performance. This combined approach has the potential to reduce interstory drift and floor acceleration, thereby mitigating both structural and nonstructural damage. Negative stiffness behavior is typically achieved through precompressed spring mechanisms coupled with geometric amplification systems. However, due to the inherently unstable nature of negative stiffness, careful design is required to ensure system stability and reliable performance. This study investigates the design considerations and seismic performance of structures equipped with negative stiffness devices through analytical modeling and nonlinear time-history analysis.