The Italian Building Code [NTC, 2008] requires that any structure be designed to withstand earthquakes according to the concept of the strength hierarchy, to prevent any form of brittle collapse mechanism. In this picture, foundations are not intended to be an exception. Nevertheless, a deeper insight into the code requirements reveals that the above concept is not applied rigorously to foundations. In fact, according to the NTC the effect of actions on any type of foundation has to be selected among: the capacity bending moment (of the structural vertical member), the actual bending moment multiplied for an amplification coefficient, or the actual bending moment evaluated by the elastic spectrum. As a conse-quence, it is accepted that the collapse of the foundation could be anticipated by the occur-rence of a plastic mechanism of the pertaining structural vertical member. In other words, the foundation is not considered as a superior structural component from a hierarchical stand-point. The aim of this technical note is to discuss a proposal for updating the NTC, where the concept of strength hierarchy is fully considered also in the case of foundations.

Osservazioni sulla valutazione delle azioni in condizioni sismiche per le verifiche agli SLU di fondazioni superficiali

AVERSA, STEFANO;DE SANCTIS, Luca;MAIORANO, Rosa Maria Stefania
2014

Abstract

The Italian Building Code [NTC, 2008] requires that any structure be designed to withstand earthquakes according to the concept of the strength hierarchy, to prevent any form of brittle collapse mechanism. In this picture, foundations are not intended to be an exception. Nevertheless, a deeper insight into the code requirements reveals that the above concept is not applied rigorously to foundations. In fact, according to the NTC the effect of actions on any type of foundation has to be selected among: the capacity bending moment (of the structural vertical member), the actual bending moment multiplied for an amplification coefficient, or the actual bending moment evaluated by the elastic spectrum. As a conse-quence, it is accepted that the collapse of the foundation could be anticipated by the occur-rence of a plastic mechanism of the pertaining structural vertical member. In other words, the foundation is not considered as a superior structural component from a hierarchical stand-point. The aim of this technical note is to discuss a proposal for updating the NTC, where the concept of strength hierarchy is fully considered also in the case of foundations.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11367/29704
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