Abstract
The present report is concerned with the results of shaking table tests of L-shaped piping supported by the semiactive damper which the authors have developed for piping systems. The damper is composed of a ball screw, a disk brake and piezoelectric actuators. The brake force is controlled corresponding to seismic responses of the piping or input accelerations. L-shaped piping of length 3 m × 3 m and outer diameter 60.5 mm is used as a piping model in shaking table tests. Both ends of the L-shaped piping are rigidly attached to the shaking table through supporting walls. The semiactive damper is attached between the bent section of the piping and the shaking table. Input accelerations used here are EL Centro (1940) NS and Akita (1983) NS normarized to be 2 m/s2 at the maximum acceleration. The results may be summarized as follows : (1) The deflection of the L-shaped piping can be reduced successfully by the semiactive damper. (2) The semiactive damper has the effect of vibration suppression even by simple control method such as on-off control or proportional control. (3) The results of shaking table tests of the piping agree approximately with the calculated results.
