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Abstract
This Thesis presents vibration control of two civil engineering srrL:(turcs (lmi!dings and
bridges) due to earthquake effect.
For buildings, the model is subjected to EL-Centro and/or Takoshi-okj earthquake horizontal component, while the bridge is subjected to EL-Centro vertical component which has a larger etTect than the horizontal component.
Newton’s second law of motion and the intluence coetficient mdh)d 2.fe applied to obtain the mathematical model of the structures.
Magneto-Rheological (MR) dampers are placed between the stories, in case of buiIdings, and at the location of the bearing, in parallel with the helical spring, in ca..se of bridges. Base isolation technique is studied; the MR dampers are compared with the passive dampers installed between the base of the building and the ground.
For high rise buildings MR dampers are used between each two adjacent floors, or if there are two adjacent buildings they can be coupled by a coupling link. consistiflg of viscous dampers or MR dampers.
Several control algorithms including the decentralized bang-bang controller_ the Lyapunov controller, the modulated homogeneous friction controller, the ma..ximum ener!:,’Y dissipation controller, and the c1ipped-<>ptimal controller are applied with the MR damper.
The MR damper gives the best reduction in acceleration, also the best reduction in the maximum inter-story displacement; also the max.imum displacement of the top story is reduced.
Also, in bridge, when the MR dampers are used in parallel with helical springs it give the best response reduction. But when MR damper is used with a tuned mass it !:,>ivcs a very high acceleration, which is not recommended to be used in this case.