The Control of Structural Vibrations By Passive & Active Systems

The control of structural vibrations produced by earthquake or wind loads can be done by various fundamental means. These conceptual approaches include modifying rigidities , masses , damping , or shape , and specially by providing passive or active counter forces .To date, passive & Active Systems of structural control have been used successfully and newly proposed methods offer the possibility of extending applications and improving efficiency.In recent years, considerable attention has been paid to research and development of structural control devices . Furthermore , serious efforts have been undertaken in the last two decades to develop the structural control concept into a workable technology.It is now established that structural control is an important part of designing important new structures , such as hospitals , and , in some cases , for retrofitting existing structures for earthquake and wind . However , to date most existing and planned strategies are Base isolation or passive tuned mass approaches .Over the years , many control algorithms and devices have been investigated , each with its own merits depending on the particular application and desired effect .Clearly, the ability to make direct comparisons between systems employing these algorithms and devices is necessary to focus future efforts and to set effective goals and specifications