Inelastic earthquake control of weld failure part I: Limit state approach

Active structural control of inelastic response is proposed for the first t ime on existing buildings. The optimal linear control theory and the force analogy method are combined in state space form to calculate the response o f the structure. Application of this combined method is performed to reduce the risk of weld failure in steel buildings. A six-story moment resisting building damaged during the 1994 Northridge earthquake is used to study the sensitivity of the response and the magnitude of the structural control fo rce to the earthquake ground motion. The limit state approach is used to de sign the structural control system by limiting the maximum plastic rotation s in the building to an acceptable level. In the process, structural contro l is shown to be very effective in reducing the plastic rotations during ex citations, and therefore reducing the risk of weld failure. In addition, st ructural control is effective in reducing the responses, which include disp lacement, velocity, acceleration and drift of the structure. Copyright (C) 1999 John Wiley & Sons, Ltd.