Earthquake simulator testing and seismic evaluation of suspended ceilings

Past seismic events have demonstrated the vulnerability of suspended ceilings, classified as nonstructural components, to earthquake damage. Engineers, architects, and manufacturers all participate to help ensure that the units perform satisfactorily during earthquakes. To address the seismic susceptibility, the U.S. national codes and federal and regulatory guidelines recommend two distinct approaches. The first mandates capacity and installation requirements and the second addresses damage states, introducing performance based. Application of these methods entails either accurate structural analysis or seismic qualification by experimentation. Until recently, scant data were available to evaluate the adequacy of the required installations or the damage states. To address this issue, full-scale earthquake laboratory tests of suspended ceiling systems have been undertaken by researchers and manufacturers. Experimentation showed that ceilings meeting the code requirements performed well. The only mode of failure observed during the tests was the loss of panels. Laboratory data were also used to construct fragility curves for the specimen. Large vertical accelerations, typically not observed in the field, dislodged panels close to the center of the test frame. This type of response differs from that presented in past earthquake reconnaissance reports and thus necessitates further examination.