Document Type : Research Article
Civil Engineering Department, Isfahan University of Technology
Active control of structures is to keep the dynamic response of stories under a predefined threshold to save the building from excessive damage. Seismic damage has a strong correlation with drift, and control of drift is simply possible in an active control process. Through a regression analysis for many cases, the Park-Ang damage index is approximately re-written based only on story drifts to enhance the common active control procedure to make it able to control the seismic damage. It is shown that the enhanced procedure is successful to keep the damage index values along building height under a predefined distribution. The active control procedure is developed based on the linear quadratic regulator (LQR) algorithm and is used to actively control buildings having up to 10 stories. The target is limiting the story damage index to a prescribed value. Seven consistent earthquake records are used for nonlinear dynamic analysis of concrete structures being 1, 2, 3, 6 and 10 stories in height. The calculated maximum relative difference between the estimated and exact damage indices is shown to be less than 10%. Four earthquake records, different from the suit of ground motions used for developing the damage index equation, are used for testing the developed procedure. It is demonstrated that by using the story drifts estimated by the developed equation, the desired distribution of story damage indices can be established with an excellent accuracy.