A computer controlled system for earthquake protection of structures

This paper investigates the feasibility of developing an active system for the protection of structures against earthquakes. The system is incorporate d in a specially designed supporting base. A computer simulation of the sys tem is utilized for selecting the design parameters of the base and the sup porting elements. The system is controlled according to preprogrammed rules in order to minimize the forces transmitted to the structure. The inputs t o the controller are the signals from appropriately placed off-site seismic detectors. A single degree of freedom structure is considered to represent the fundamental vibratory mode of the structure which is generally respons ible for the largest component of its dynamic response to ground excitation . An illustrative example shows that the proposed system is implementable a nd can result in orders of magnitude reduction in the transmitted force to the structure. It can also minimize the torsional effects resulting from an y arbitrary distribution of the mass for non-symmetrical structures.