Shake table tests on clutter levels of typical medicine shelves and contents subjected to earthquakes

Overturned shelves and fallen objects scattered on floors are one of the most frequently observed forms of nonstructural damage after earthquakes. The term ‘clutter’ is adopted in this study to represent this type of damage. Clutter may cause obstructions and thus hinder the use of a room. Making a seismic evaluation of clutter is a daunting task, due to the diversity of the types of shelves and objects and the way the objects are stored. Nonetheless, in order to achieve performance‐based seismic evaluation, especially for critical facilities such as hospitals, it is reasonable to undertake the estimation of clutter when examining the association between the performance of structural and nonstructural elements. Of particular interest in this paper is clutter caused by objects stored on medicine shelves in pharmacies, which are one of the critical departments for delivering post‐earthquake emergency care. Shake table tests were conducted on three conventional types of medicine shelves. Sinusoidal waves and earthquake motions were input uniaxially. The results of the tests using the sinusoidal wave input indicated the relationship between the input excitation intensity and clutter level expressed in scattering distance from the front of the shelf. Tests using earthquake motion input were then conducted and the results were compared with those for sinusoidal waves. Based on a comparison of the results from these tests, criteria for the seismic evaluation of clutter caused by medicine shelves due to earthquakes were proposed. Copyright © 2011 John Wiley & Sons, Ltd.