Abstract
Along with the increasing number of disasters caused by large earthquakes in Japan, there is a desire that structures such as tall buildings and viaducts are strong and safe against earthquakes to be confirmed. In addition, from the findings obtained from the damage, earthquakes with new characteristics such as long-period earthquakes attracted attention, reexamination of seismic designs so far become important, and it becomes necessary to clarify the destruction process of structures and the seismic resistance in vibration tests. This paper introduces a methodology to compensate a reaction force of hydraulic shaking tables for earthquake resistance testing facility. The motion of a shaking table is affected by a reaction force caused by a specimen on the table in the seismic testing. The controller is designed by using DMM (Dual Model Matching) based on the characteristic transfer function. We adjust the feedforward controller and the feedback controller to reduce the influence of the reaction force. In addition we propose the control method to compensate the characteristic change of the specimen by using reaction force. The effectiveness of the proposed method is confirmed by using a single-axis hydraulic shaking table, and verified by installing a mechanism for changing the natural frequency of the specimen under excitation.
