Performance and Protection of Base-Isolated Structures under Blast Loading

Abstract

Terrorist attacks are a growing threat worldwide. Explosive devices, the weapon of choice for a majority of these attacks, significantly threaten civilian and military personnel. Seismic ground motions are also associated with catastrophic structural failures, and due to their infrequency, seismic-resilient designs aim at protecting the life-safety of occupants. The area of structural control for seismic hazard mitigation is well-researched and similar strategies that safely concentrate deflection or safely dissipate energy on the global structure hold some merit in the face of blast loading. Although blast and seismic loading are two different phenomena from a fundamental physics perspective, base isolation, as one of the most robust and popular passive control technologies, has significant potential to mitigate damage from other impulsive sources such as blast. The goals of this study can be summarized as (1) demonstrating the potential for base isolation to protect from blast loads, and (2) improving the response of base-isolated structures under blasts without compromising seismic protection. Through numerical simulations of a low-rise structure, beneficial effects of using base isolation to reduce interstory drifts and absolute story accelerations seen in earthquake engineering were also observed for blast loading. Furthermore, the proposed supplemental control devices were able to maintain nominal base isolation performance under smaller excitations while restrict damaging base displacements under larger excitations. Both nonlinear bumpers and tuned-mass dampers were considered as supplemental devices, with the former enforcing safe maximum base displacements and the latter improving overall root-mean-square behavior.