The CERL Equipment Fragility and Protection Procedure (CEFAPP): Experimental Definition of Equipment Vulnerability to Transient Support Motions.

Abstract : The CERL Equipment Fragility and Protection Procedure (CEFAPP) is a new testing protocol that defines the capacity of equipment to withstand seismic and other transient support motion in terms of amplitude versus frequency. The amplitude is the support motion or response spectrum amplitude at which failure occurs. Failure may comprise actual mechanical damage, temporary loss of function, acceleration or strain levels at critical locations, or any other user-defined criteria. The frequency content of support motion is critical as it determines the manner (modes) in which equipment responds and fails. CEFAPP uses narrow-band random sweep tests to determine the amplitude, frequency, and mode of failure, and records these as single data points for each failure. All failure data are plotted, and confidence bands may be plotted across the spectrum if enough failure data are gathered. CEFAPP was validated through time history, site-specific spectra, and design spectra testing of equipment. Design engineers can define predicted motions at equipment installation locations and overlay these data onto the experimentally defined equipment capacity plots to evaluate the adequacy of equipment. Equipment manufacturers can test their equipment according to CEFAPP as a design aid, because the test results define improvements needed to withstand potential demands.