MODIFIED RESPONSE SPECTRUM ANALYSIS FOR CONTROLLED STRUCTURES SUBJECTED TO EARTHQUAKE EXCITATION

Abstract

One case of the earthquake analysis is the response spectrum analysis. Where the structure is designed to protected by earthquakes which represented from design spectrum. However, very often the real earthquake that applied to structure exceeds the design spectrum. In that case the ductility of structure and the demand capacity are the line of defence to face that situation. As a results damage will occurred in structure and the cost of rehabilitation is unavoidable. An alternative direction which proposed in this paper is to design structure, equipped by control devices, capable to resist the incoming earthquake and remaining in elastic range and thus without damage. The idea is that once the response spectrum of the incoming earthquake is higher than the design spectrum at the eigperiods of the structure the control devices will be activated, in order of milliseconds, and will change the period of structure. In that case the structure will avoid the “resonance” with the incoming earthquake and its response spectrum will lie lower that the design spectrum at the new eig-periods of the structure. From the numerical results it is shown that the above control strategy is efficient in reducing the response of building structures, with small amount of required control power.