Experimental and numerical analysis of wheeled medical equipment with adjacent wall subjected to earthquakes

Equipment supported on wheels can be regarded as a particular type of sliding rigid block, which is commonly used in hospital buildings and plays a vital role in the treatment process. Damage to the equipment can have incalculable and potentially catastrophic consequences for the safety of patients. However, the research on the seismic performance of wheeled building contents is still limited. In this study, two pieces of critical medical equipment, a ventilator and an anesthesia machine, were selected to conduct unidirectional shaking table tests in order to investigate the seismic performance of wheeled equipment under different conditions and environments. The test results demonstrated that the specimens had different dynamic responses under the locked and unlocked condition of wheels; unlike ordinary rigid blocks, uneven friction caused more displacement to the wheeled equipment, which increased the risk of potential damage. Based on the experimental results, equivalent numerical models of uneven friction were developed to quantify the effect of damage factors, which had good predictive capacity for equipment with locked wheels. Seismic fragility curves of wheeled equipment were derived for engineering application by using incremental dynamic analysis.