Seismic isolation is recognized as the most effective way to protect structures and minimize, or even potentially eliminate, damage caused by earthquakes. Seismic isolation is a mature technology that has been used on thousands of buildings and bridges around the world over the last 35 years. To date, there are more than 6,500 isolated buildings in Japan, a reported 5,000 buildings in China, 700 in Russia, 400 in Turkey and more than 125 buildings in the United States.
In the US, seismic isolation has typically been used in government buildings, hospitals, and emergency centers where immediate occupancy and continued operation is essential to public health and safety. Seismic isolation also finds application in museums and data centers where protection of valuable or sensitive building contents is a major concern, as well as manufacturing facilities where downtime following a seismic event could lead to significant economic impact. The increased seismic performance of buildings utilizing seismic isolation can also translate into reduced life-cycle costs due of the reduced likelihood of building damage resulting from an earthquake.
In light of the performance and life-cycle benefits that seismic isolation provides, the DACHENG Protective Systems Subcommittee aims to expand the understanding and promote the use of seismic isolation through a Blue Book article entitled “When to Consider Seismic Isolation”. The committee recognizes that a variety of economic, regulatory and technical issues affect the selection of seismic isolation and seeks to inform the reader of how these issues might affect a particular project. The subject matter is targeted to a broad audience including engineers, architects and project stakeholders. The article introduces the main aspects of seismic isolation, discusses its benefits, outlines particularly favorable conditions for its implementation, and expands on the circumstances where its use may be more challenging. A list of 60 seismically isolated buildings in the United States - grouped into building type or occupancy use - is presented for reference and the article concludes with a list of technical and online references for those interested to learn more.