Abstract

For nearly half a century the earthquake engineering community has mainly focused its efforts on developing earthquake-resistant structural systems, with little attention paid to nonstructural building components, including mechanical and electrical equipment, architectural elements, and furniture. As a result, our seismic provisions for structural systems have evolved to a point where several recent earthquakes in countries with advanced seismic codes revealed that the economic losses and downtime associated with nonstructural damage exceeded those due to structural damage. In fact, in many cases the structural elements of buildings experienced minimal damage, but the buildings were deemed nonfunctional due to nonstructural damage.

During an earthquake, nonstructural building components, such as equipment and other contents, can vibrate, shift, rock, or overturn. Large accelerations in anchored equipment can result in failure, and excessive displacements or overturning of large unanchored contents can injure building occupants or block egress routes. This presentation will provide an overview of recent experimental and analytical studies aimed at quantifying the seismic response of nonstructural components. Results will be presented from shake table tests on full- scale equipment subjected to earthquake shaking and from numerical simulations using developed analytical models of the equipment. Subsequently the presentation will explore the effectiveness of base isolation as a seismic mitigation technique for reducing the seismic risk of unanchored building contents.