Seismic Fragility Analysis of Suspended Ceiling systems

The failure of suspended ceiling systems has been one of the most widely reported types of nonstructural damage in building structures in past earthquakes. Despite repeated damage to such systems, there has been no systematic study of their seismic behavior beyond qualification studies for selected manufacturers. Fragility methods are used herein to characterize the behavior and vulnerability of suspended ceiling systems. Since suspended ceiling systems are not amenable to traditional structural analysis, full-scale experimental testing on an earthquake simulator was performed to obtain fragility data. The results from the full-scale testing are presented as seismic fragility curves. Four variables that affect the seismic performance of suspended ceiling systems were investigated: (1) the size and weight of tiles, (2) the use of retainer clips, (3) the use of compression posts, and (4) the physical condition of grid components. A total of six ceiling system configurations were studied using different combinations of these variables: (1) undersized tiles, (2) undersized tiles with retainer clips, (3) undersized tiles with recycled grid components, (4) normal sized tiles, (5) normal sized tiles with retainer clips, and (6) normal sized tiles without the compression post. Four limit states of response that cover most of the performance levels described in the codes and guidelines for the seismic performance of nonstructural components were defined using physical definitions of damage. Data were obtained for every limit state to compare the effect of each variable on the response of suspended ceiling systems.