Report - PEER - University of California, Berkeley

SEISMIC FRAGILITY OF SMALL EQUIPMENT AND CONTENTSTara HUTCHINSON 1 and Samit RAY CHAUDHURI 2ABSTRACTThis paper presents analytically developed seismic fragility curves for unattached benchmountedequipment and contents. The emphasis of the study is on rigid scientific equipment,which is often placed on the surface of ceramic laboratory benches in science laboratories orother buildings. Although theoretical solutions are available to determine the seismic responseof rigid sliding blocks and research has been conducted to develop the analytical fragilitycurves, previous studies have not considered the uncertainty of important input parameters andhow they affect the shape and distribution of the curves. Moreover, for scientific equipmentmounted on benches, limited experimental data are available regarding the dynamiccharacteristics of the typical support systems and the equipment frictional behavior.For this study, only uniaxial seismic excitation is considered to provide insight into thecontributions and sensitivity of the fragility to different uncertain parameters. Uncertainparameters considered in this study include: (i) static and kinetic coefficients of friction and (ii)supporting (bench and building) characteristics. In this paper, generalized fragility curves forsliding-dominated equipment are provided for use in seismic performance assessment.Keywords: Nonstructural response; Seismic fragility; Equipment response; and Friction.1. INTRODUCTIONScientific equipment such as analyzers, microscopes, centrifuges, monitors, andcomputer workstations, are often placed on the surface of ceramic laboratory benchesin science laboratories. Damage to these items has gained significant attentionfollowing recent earthquakes, largely due to the potential for significant economiclosses and/or research downtime. Many of these types of scientific equipment arefairly costly and loss of functionality would result in total economic loss of theequipment itself. In addition, in hospital or other critical buildings, failure of suchequipment may hinder emergency response efforts immediately after an earthquake.However, in comparison with structural systems, there is little research on theperformance of these equipment and contents, particularly with respect tounderstanding the characteristics of the varied support (bench and building)conditions and their frictional behavior.1 Asst. Professor, Dept. of Civil and Environmental Engineering, University of California, Irvine2 Graduate Student, Dept. of Civil and Environmental Engineering, University of California, Irvine197