Building Critical-Mode Control Nonstationary Earthquake

A method of optimal open-loop critical-mode control has been applied to building structures excited by earthquake that is modeled as a nonstationary random process. The time dependent statistics of building response quantities and required active control forces have been presented. Monte Carlo simulations for building response quantities with or without active control systems have been performed to demonstrate the behavior of buildings subject to earthquake excitations. It is shown that a significant reduction for the building response can be achieved by use of active control systems. Furthermore, the required active control forces computed based on the stationary earthquake model are too conservative. A sensitivity study has been carried out to determine the effect of uncertainties involved in estimating structural properties on the results of optimal control. The active tendon control system is not sensitive to the estimation uncertainties for the damping and stiffness of the building. Although the active mass damper system is not sensitive to errors in damping estimation, it is moderately sensitive to the stiffness uncertainty of the building.