Vibration investigation of passive control using rubber bearing
Computing, Health and Science
A five-storey benchmark building model is base-isolated using six identical rubber bearings, and subjected to four different ground motions including the Northridge 1994, Hachinohe 1968, El- Centro 1940, and Kobe 1995 earthquakes. Vibration responses of the building model with and without rubber bearings were calculated from the corresponding equations of motion. It was found that the isolation effectiveness offered by the bearings to the vibration inputs is strongly dependent on the type of earthquake motion. For example, the vibration response of the isolated model was improved when subjected to the Northridge 1994, Hachinohe 1968, and Kobe 1995 earthquakes, but the best results were obtained when the Hachinohe earthquake was applied. The maximum accelerations, displacements, inter-storey drifts and base shear force as well as over-turning moment for the baseisolated model are significantly reduced, and the vibration amplitude of the accelerations, and interstorey drifts decreased much more quickly with time than those without rubber bearings. The contribution of the second vibration mode to earthquake response was also identified. On the other hand, the present isolators failed to produce an effective protection against the El-Centro 1940 earthquake.