Aseismic toughness of structures

The paper aims to give an approximate evaluation of the ductility and strength demand so that a structure can resist strong earthquakes of an assigned intensity level. It is shown, by means of a suitable energy balance equation, that the aseismic capacity of structures depends on a special coupling of strength and ductility defined as aseismic toughness. A broad evaluation of the toughness ratios that can be achieved in reinforced concrete structures ends the paper.