The problem of the durability of reinforced concrete structures is arisen, dramatically, in the last decades, showing that one of the most dangerous degradation phenomena is connected to the rebars corrosion. When active corrosion grows the oxides occupy a volume of about 2–4 times, with respect to the sound bar, causing a loss of bond, cracking and cover spalling. In this paper the corrosion effects at the steel–concrete interface are analysed. At this aim, pull-out tests are carried out, with different corrosion levels, for the definition of the bond-slip constitutive relationships of the damaged rebars. Furthermore, an analytical model is developed for evaluating the internal pressure due to corrosion products, for concrete specimens without stirrups, in order to provide a procedure for the definition of the maximum bond as a function of the corrosion percentage. Finally the analytical results are validated through a comparison with the experimental outcomes

Masonry arch systems and vaulted structures constitute a structural typology widely spread in the historical building heritage. Small displacements of the supports, due to different causes, among which subsidence of foundation systems or movements of underlying structures can lead the masonry arch to a condition of collapse because of gradual change in its geometry. This paper presents a tool, based on a kinematic approach, for the computation of the magnitude of the displacements that cause the collapse of circular arches subject to dead loads, and allows the evaluation of the related thrust value. A parametric study has been carried out in order to develop a deeper understanding of the influence of the involved parameters. In addition, analytic formulations of the maximum allowed displacement and the associated thrust are proposed. Finally, a case study related to the behavior of a masonry arch on spreading-induced abutments is undertaken and discussed.

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