Microvibration control of coupled high tech equipment-building systems in vertical direction

Vertical ground motion induced by a moving train is one of the major sources of environmental loads that affect the normal operation of sensitive equipment installed in a high tech building nearby the railway. This paper investigates the microvibration level of a high tech building subject to nearby train-induced vertical ground motion and its mitigation using a hybrid control platform for sensitive equipment. The hybrid platform is an elastic body mounted on the building floor through a series of passive mounts and controlled by hydraulic actuators with a sub-optimal control algorithm. The finite element model and the governing equations of motion of the coupled platform-building system are established in the absolute coordinate to facilitate the feedback control and performance evaluation of the platform. The time histories of vertical ground motion are generated from the ground motion spectra that are the functions of track, train, and soil parameters. Numerical simulation and parametric studies are conducted on a typical three-story high tech building. The results show that the use of hybrid control platform can effectively reduce vertical microvibration of a batch of high tech equipment to the level satisfying the most stringent microscale velocity requirement specified in the BBN criteria. The hybrid control platform is superior to the passive platform because of its higher performance and robustness.