Shake table investigation on the seismic performance of hospital equipment supported on wheels/casters

Abstract

Summary This paper presents an experimental investigation on the seismic response of medical equipment supported on wheels and/or casters. Two pieces of equipment were tested: a large ultrasound machine and a cart carrying smaller medical equipment. In the first phase, the resistance of the wheels and casters of the equipment was characterized through a controlled‐displacement procedure on the shake table. In the second phase, an extensive shake table test program was carried out to investigate the seismic response of the equipment. The input signals for the shake table tests included floor motions of a four‐story steel braced‐frame hospital designed to satisfy seismic requirements of a site in the Los Angeles area. The results of 96 shake table tests reported in this study include the seismic performance of the equipment under both unlocked and locked conditions, located on various floor levels of the building. It was observed that engaging the casters' locking mechanism does not necessarily decrease the relative displacement. The displacement response was sensitive to the excitation intensity and the orientation of the equipment with respect to the input excitation. Based on the experimental observations, appropriate structural engineering demand parameters associated with the relative displacement and relative velocity demands of the equipment are proposed and used to develop conditional probability curves. Finally, in an effort to extend the results of this experimental study to similar equipment on wheels/casters, the performance of a simple numerical model in predicting the peak seismic demands is evaluated. Copyright © 2016 John Wiley & Sons, Ltd.

Experimental assessment of the seismic performance of hospital cabinets using shake table testing

“…A dimensionless acceleration intensity measure (IM) was used, along with an engineering demand parameter previously developed . Nikfar and Konstantinidis assessed on shake table the experimental response of hospital equipment supported on wheels/casters. Experimental observations were used to find the most appropriate structural engineering parameters correlated to the sample nonstructural components, namely relative displacement and velocity.…”

Energy Loss in Systems of Stacked Rocking Bodies

“…A multi-block model was developed in (Kounadis et al, 2012) where the simplified assumption of no loss of energy during impacts for each body in the system was adopted. Other type of rocking systems have been presented for rocking frames in (Makris and Vassiliou, 2014;Dimitrakopoulos and Giouvanidis, 2015), for rocking bodies on base isolation in (Harvey Jr, 2017;Vassiliou and Makris, 2012), for rocking bodies with casters in (Chatzis and Smyth, 2012a;Nikfar and Konstantinidis, 2017) and for a statuepedestal system in (Wittich and Hutchinson, 2016).…”

Dynamic Response of a Rigid Slab Supported by Four Rigid Cylinrical Rocking and Wobbling Columns

“…Indeed, a simple freestanding rocking block has been systematically studied for more than five decades both when the block is assumed rigid [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] and when it assumed deformable [27][28][29][30][31][32][33][34][35][36][37]. Small scale experiments have been also performed [38][39][40][41][42][43][44][45][46][47][48][49][50][51]. It has been proven that structures that rock inplane (2d rocking) have remarkable dynamic stability.…”