Causal semiactive control of seismic response

A challenge in the use of semiactive dampers for the earthquake response reduction is the development of implementable control algorithms. Exact optimal control resulting from the numerical solution to Euler–Lagrange equations requires a priori knowledge of earthquake in the control interval, which is not possible. This paper proposes a causal sub-optimal implementable control to reduce the earthquake response using an inherently nonlinear controllable fluid damper. The proposed method is basically based on the prediction of the near-future ground accelerations using maximum-entropy method. The earthquake response of low-rise, two degree of freedom (dof) base isolated structure is investigated for the proposed causal sub-optimal control and the resulting performance is compared to the exact optimal control and the uncontrolled case. The results show that the proposed control is promising in protecting the earthquake-excited buildings.