Using seismic isolation and energy dissipation to create earthquake-resilient buildings

Seismic isolation with energy dissipation is a technology that has been used in New Zealand since 1978 for bridges and buildings. During this period it has seen limited use, tending to be applied mainly to historically significant buildings, or buildings that have special functional requirements. Seismic isolation has the ability to significantly improve the seismic performance of existing buildings through a seismic retrofit, or to create new earthquake-resilient buildings. Both of these applications are of greater relevance throughout New Zealand following the Canterbury earthquakes. Consequently, the consideration of seismic isolation is no longer limited to those buildings at the top end of the Importance Level spectrum. This paper examines the broad technical issues associated with isolation and energy dissipation. It discusses the benefits and costs of seismic isolation, and presents guidelines for cost estimation at the feasibility stage of projects. We will explore the cost-benefits for building owners, and discuss whether base isolation can replace earthquake insurance for the building and its contents, and business interruption insurance.