Actual standards for constructions, according to the capacity design approach, prescribe the realization of buildings in which plastic hinges shall develop in correspondence of the ends of structural elements. The full knowledge of the cyclic seismic behaviour of steel reinforcing bars is necessary for the global understanding of the structural behaviour of the building, strictly dependent on the ductile properties of bars in those sections where plastic phenomena are located. Two aspects shall be widely discussed, related to the definition of the effective seismic demand (D) on the rebars due to earthquakes and to the mechanical cyclic capacity (C) of reinforcements. In the present work, developed inside the framework of a European research project called Rusteel (2009), the results coming from an accurate analysis of the seismic behaviour of r.c. structures are presented, evidencing the levels of strain and dissipated energy due to earthquake events on rebars. The mechanical characterization of the low-cycle fatigue (LCF) behaviour of bars commonly used in r.c. buildings was then executed, taking into account also the effects of corrosion phenomena due to aggressive environmental attacks, allowing the comparison between ductile requirements due to seismic action (D) and ductile capacity of steel reinforcing bars (C).
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