Shaking Table Tests of Critical Equipment With Simple Isolators

Because the earthquake is one kind of non-predictable calamity and happens suddenly, its disaster and consequence are larger than other calamities. Mankind must face not only the emotional effects caused by earthquakes, but also the damage to the structure and substructure systems. The fire, damaged pipeline systems cased by earthquake and the destruction of the semiconductor, equipment or microelectronics in high-tech factories will cause an enormous and a chain of economic losses. Therefore, there is a need of an economical and efficient method to protect equipments from earthquake damage. Namely, in addition to promoting the earthquake-resistant capacity of structures, it is also important to ensure the safety of the expensive equipment and facilities. In this study, it is aimed at developing a new simple isolator with appropriate damping for critical equipment. The basic principle of the simple isolator is to lengthen the natural period of equipment, and simultaneously to reduce the earthquake-induced energy and the displacement of the isolator by additional damping. A series of shaking table tests for critical equipment isolated with simple isolators were carried out in the Department of Civil Engineering, Feng Chia University, Taichung, Taiwan. From these test results, it is illustrated that the simple isolator can reduce more than 80% responses of accelerations under earthquakes with peak ground acceleration of above 0.450g. Therefore, the simple isolator can be recognized as a feasible and promising way in mitigating the seismic responses of equipment. In addition, the simple isolator possesses enough energy absorbing capacity to reduce its maximum displacement and the restoring force to bring the isolator back to the original position without significant residual displacement.