Controlled semiactive hydraulic vibration absorber for bridges

Heavy truck traffic on highway bridges is known to produce impact loads that cause large vibrations. This phenomenon can reduce the expected service life of many highway bridges. A means to mitigating those deleterious vibrations using an automatic control system that requires no pumps or line power is proposed. A semiactive hydraulic bridge vibration absorber that can be retrofitted to an existing bridge is described. The bridge/vehicle system is modeled, and a practical feedback control that uses either strain-gauge or accelerometer readings to sense the state of the system is synthesized. The results of an experimental test of the new system indicates reductions of peak amplitudes of 65-70%.