Analisi strutturale del "Voltone" sottostante la piazza della Repubblica a Livorno

Briccoli-Bati S., Girardi M., Lucchesi M., Padovani C., Pellegrini D.

Masonry buildings  Nonlinear elasticity  Numerical methods 

We present in this paper a nonlinear structural analysis of the "Voltone", a large vaulted masonry tunnel located beneath "Piazza della Repubblica" square in Livorno, Italy. The safety of the structure is numerically assessed via the NOSA-ITACA finite element code (www.nosaitaca.it), under permanent and accidental loads. The most adopted assessment procedures for masonry bridges and tunnels are based on the limit analysis and are aimed at providing an estimate of their load carrying capacity (Heyman, 1982, Gilbert, 1997, Brencich, 2009, Cavicchi & Gambarotta, 2007, Fanning & Boothby, 2001, Oliveira et al., 2010). On the contrary, in the study presented here a nonlinear incremental approach is followed. Masonry is modelled by a masonry-like constitutive equation with zero tensile strength and bounded compressive strength (Lucchesi et al., 2008). The "Voltone" is constituted by a segmental vault, through which the "Fosso Reale" canal flows. The vault is set on two lateral walls and strengthened by buttresses placed at intervals of about 5.8 meters one from the other. Under permanent loads, such as the weight of the structure and of the filling material, and the earth pressure acting on the walls, a "tight crowd" load in the central region of the square and the traffic loads on the square's ends are modelled. All loads are applied to the structure in accordance with the load combinations for ultimate limit states. The analyses have enabled assessing the structure's safety in light of current Italian regulations (D.M. 14 gennaio 2008 and Circolare 2 febbraio 2009). This case study, conducted in collaboration with the Municipality of Livorno and with the financial support of the Region of Tuscany, on the one hand provided an opportunity to validate the NOSA-ITACA code, on the other highlighted the key role played by numerical tools in assessing the safety of ancient masonry constructions and supporting institutions and designers during maintenance and restoring operations.

Source: SAFE MONUMENTS - Conservation vs Safety of Monumental Historical Constructions = Tra Conservazione e Sicurezza di Edifici Monumentali e Costruito Storico, Firenze, 28 marzo 2014