Active control of across-wind responses of tall building

Modern tall buildings that use high strength and lighter construction-materials aremore flexible and are therefore susceptible to wind-induced excitations resulting in discomfort for the occupants discomfort and a state which is structurally unsafe. It is therefore necessary to establish the methods which can be used to reduce such a wind-induced response at the preliminary design stage. Most of the studies in recent times have been formulated using actuator force as an active control force based on modern control theory of linear quadratic optimum algorithm. This is done to estimate the wind-induced response and then the actuator control force necessary to reduce the excessive wind-induced vibrations. A lot of time is required and the cost is high for the wind tunnel test that is requires, so the numerical simulation approach is recommended as an alternative. Simulating the wind load in time domain from known spectra data is particularly useful for some response calculations which are based on narrow banded processes such as across-wind responses of tall buildings. This simulation procedure is taken from Deodatis. In this study, fluctuating across-wind load acting on a tall building is simulated in time domain using across-wind load spectra theory as stipulated by A. Kareem in 1982. Afterwards, this simulated time series of wind load is used to calculate across-wind responses, the optimal control forces and controlled responses based on the linear quadratic regulator (LQR) controller.