Un modello costitutivo per il calcestruzzo e sue applicazioni nell'analisi nonlineare di strutture in c. a.

Dottorato di ricerca in meccanica delle strutture. 8. ciclo. Relatori A. Di Tommaso e T. Balan. Coordinatore E. ViolaConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Carbon-FRCM materials for structural upgrade of masonry arch road bridges

Numerous bridges of the Italian arterial road network were designed for live loads significantly lower than those produced by the current vehicular traffic. Many of them are masonry arch bridges whose load carrying capacity should be assessed for defining the necessary strengthening in-terventions. In the present paper the design criteria for strengthening masonry bridges with carbon fiber reinforced cementitious matrix (C-FRCM) materials are presented with reference to a masonry arch road bridge built right after the second world war. Methods: The structure is analyzed both in its original and in its strengthened configuration following the approach of the collapse mechanisms. The considered approach allows to capture the strengthening effect of the C-FRCM material in terms of modification of the collapse mechanism and increase of the load collapse multiplier. Two different configurations of C-FRCM strengthening material applied at the extrados have been considered. In the first configuration the ends of the C-FRCM material are anchored at the vaults imposts, while in the second configuration they are not anchored at the imposts. Results: To obtain load collapse multipliers greater than one three layers of C-FRCM strengthening material have to be applied at the extrados of all the three vaults in the case of end anchored strengthened material, while in the case of unanchored strengthening material four layers of C-FRCM strengthening material have to be applied at the extrados of all the three vaults

Experimental investigation on cyclic response of RC elements repaired by CFRP external reinforcing systems

This paper deals with the experimental results of an investigation aimed at studying cyclic response of half scaled RC specimens previously damaged and then repaired with externally bonded carbon fiber reinforced polymer sheets. The research involved the test of ten specimens. Two of them were tested without any external strengthening material in order to provide a reference for the response of repaired specimens. These latter were tested after a previous damaging procedure and a subsequent repair intervention with fiber reinforced polymer composites. The parameters under investigation were the level of initial damage, the strengthening configuration, and the level of axial load. Test results have pointed out effectiveness of the adopted strengthening systems, since repaired specimens exhibited better mechanical responses than the unstrengthened ones