Introduction to NEES TIPS: Tools for Isolation and Protective Systems

Abstract

Recent earthquakes have shown that even moderate ground shaking can produce large economic losses and major societal disruptions due to the widespread structural and nonstructural damage, and it is increasingly recognized that the traditional goal to protect against loss of life, may be insufficient. Seismic isolation offers a simple and direct opportunity to control or even eliminate damage by simultaneously reducing deformations and accelerations. While applications of seismic isolation in the U.S. have been limited to specialized facilities requiring high performance, the pace of innovation and application of isolation technology outside of the U.S. is growing at an exponential rate. A new NEES project, Tools to Facilitate Widespread Use of Isolation and Protective Systems, or TIPS, will explore innovative ideas to economically and reliably apply seismic isolation and supplemental damping to a much broader range of structures. The NEESTIPS project will fill critical knowledge gaps concerning device and system response, develop strategies and tools to reduce unnecessary costs of design and construction, and develop analysis and design tools to achieve targeted performance goals. This paper highlights the results of our strategic assessment of the knowledge gaps, economic barriers, and procedural barriers that limit the use of isolation systems in the United States. A research plan that addresses the above areas will be summarized. Through the NEESTIPS project, hybrid and shake table tests of seismically isolated building systems will be conducted at UC Berkeley and Univ. at Buffalo NEES facilities and also the E-Defense shaking table. Among the goals of the analytical and experimental program are: (1) obtain a better understanding of the behavior of full scale devices at realistic rates, (2) develop strategies for reducing design and construction costs such as relocating the level of the isolation plane or allowing the superstructure to yield, (3) identify performance limit state behavior of various isolated systems, (4) develop emerging isolation systems that can effectively achieve specific multi-level performance goals, and (5) extend performance-based design tools so that conventional solutions and isolation systems can be evaluated consistently.