Three-Dimensional Isolation System for Building Resilience to Earthquake Hazard

Board Of Regents, Nshe, Obo University Of Nevada, Reno, Reno NV

Investigators

Abstract

Building isolation systems placed between foundation and the structure are able to reduce shaking of the buildings and mitigate serious damage in earthquakes. However, recent earthquakes and large scale tests have shown that there is a large amount of damage to the interior of buildings (mechanical system, ceiling tiles etc.) and to the critical equipment in buildings (hospital and electrical equipment, telecommunication items etc.) leading to inoperability of buildings and high economic losses. These damages to the interior are primarily caused by vertical shaking of the ground in earthquakes. This project will pursue research in identification of the level of vertical shaking in buildings in earthquake and development of isolator that reduces the shaking to acceptable level. The proposed system will stack traditional isolation bearings for protection from horizontal shaking and new devices for protection from vertical shaking. The new device combines a weight bearing liquid spring and controllable damper into a single package. These isolators will have potential of use in other engineered systems where vibrations are critical. The researchers will recruit participation of underrepresented groups in the research and education efforts. In this project, basic science will be advanced through an analytical study to understand the fundamental dynamics of three-dimensional isolation of rigid bodies and flexible structures, subjected to earthquakes. Optimal properties of an effective three-dimensional isolation system will be determined. The proposed vertical isolation system uses liquid spring technology that is robust, ideal for supporting large loads and operating in harsh conditions. The novelty of the proposed system is combining the liquid spring stiffness and the controllable damping characteristics into a single, sustainable device for civil infrastructure application. The proposed system is fail-safe, such that even under power or control system failures optimal damping is retained in the passive mode since the spring action is passive. A one quarter scale device will be designed, built, and characterized in this project.