Valutazione dell’instabilità dinamica di aste in acciaio

This paper evaluates the phenomenon of dynamic instability of steel beams under repeated load- ing. In particular, the research is essential to identify those elements that have no problem in static conditions, i.e. loaded below the classic Eulerian instability load, but they could fail in dynamic conditions and possibly compromising the structural stability. In the literature, the general problem of dynamic instability was first studied by Bolotin, who sug- gested an approximate method. This method has been extended herein and very accurate regions were derived. Finally, a response spectrum analysis was conducted on a case study resembling a steel frame in order to investigate the effects of dynamic instability under seismic loading. The beams subjected to dynamic instability were identified and two possible retrofit solutions pro- posed.