INSTANTANEOUS OPTIMAL-CONTROL OF BUILDING FRAMES

A control algorithm based on the instantaneous optimal closed-loop con trol technique is presented for the control of buildings subjected to earthquake excitations. It is proposed that the building frames be mod eled using finite elements, with a two-node six-degree-of-freedom plan ar frame element as a basic tool for the example analysis. The instant aneous optimal closed-loop control algorithm is derived in second-orde r form using the Newmark integration scheme. The weighting matrices ar e so chosen that the instantaneous control technique is unconditionall y stable. Examples of the optimal control of a three-bay 10-story stee l building frame are illustrated using base isolators and active tendo ns. The input excitations chosen arc based on the NS component of the ground acceleration record of the 1940 El Centro earthquake. Results o n the reduction of the dynamic response and the control effectiveness of the passive, active, and hybrid control designs are presented and d iscussed.