1,721,051 research outputs found
Determinazione delle azioni statiche equivalenti per l'analisi di stabilità dei pendii
No full textAppendice
Subsoil characterization and stability analysis for the Bourbon del Monte Palace in Piancastagnaio (Siena, Italy)
No full textThe historical Bourbon del Monte Palace in Piancastagnaio (Siena, Italy) dates to the 17th century and represents an uncommon example of feudal architecture in Tuscany. It was inhabited until the end of the ‘80s of the last century when, due to the high degree of instability achieved, it was declared unfit for use by the Public Authorities. The Palace lays on a sloping site, on the edge of fractured trachyte blocks mixed with alluvial deposits. It is characterized by four floors above ground and a basement at the South-East corner, while the North façade has two floors. Severe degradation phenomena of the building consist of multiple cracks diffused along the external and the inner masonry; furthermore, significant water infiltration from the floor has been observed in the South-East basement since the ‘80s. Previous investigations have shown that the Palace has undergone two distinct settlements systems: one dates before the ‘70s and may have caused the cracks along the South wall of the building; the other, more recent and probably related to the water infiltration on the basement, may have caused the damage to the South-East wall. This paper investigates the source of this second settlements system by modeling and analyzing a 2D soil section close to the South-East corner of the building. Firstly, the collected geotechnical and geological data and the modeling of the analyzed section are presented. Afterwards, the results of the numerical simulations are shown and discussed, analyzing the effects of the estimated settlements on the observed structural damage
ANALISI DELLA PROBABILITÀ DI COLLASSO ARGINALE DEI GRANDI FIUMI
No full textLe mappe di rischio idraulico nei tratti fluviali protetti da arginature sono usualmente redatte ipotizzando il solo feno-meno della tracimazione, nel presupposto di argini non collassabili. Tale ipotesi non è verificata e non è cautelativa, poiché la rottura dell’argine dei grandi fiumi con la conseguente formazione di una breccia è un fenomeno non trascu-rabile che deve essere messo in conto per una stima corretta del rischio idraulico. Dopo avere brevemente descritti i principali meccanismi di collasso arginale sono richiamate le indagini di prima assegnazione utili per la sorveglianza degli argini esistenti e l’individuazione dei tratti critici. È poi descritta la metodologia di analisi della probabilità di col-lasso di una sezione d’argine, attraverso la determinazione delle curve di fragilità al variare dell’altezza idraulica per i principali meccanismi di collasso e della curva di fragilità composta. La stima della probabilità di collasso è eseguita con metodo di Taylor (FOSM) e/o con metodo MonteCarlo (MC). È quindi proposta una procedura semplificata per determinare la curva di fragilità composta di un tratto di argine omogeneo, assumendo come variabile aleatoria indipendente la portata del corso d’acqua. A titolo di esempio delle condizioni degli argini dei grandi fiumi, la procedura di analisi della probabilità di collasso è applicata ad un tratto del fiume Po
Thermal Conductivity of Cement–Based Grouts for Energy Micropiles: Preliminary Experimental Investigation
No full textEnergy micropiles are a kind of energy geostructure designed to reduce the energy consumption of buildings combining structural and thermal performance. Since a common way to improve the thermal efficiency of an energy pile is to increase the thermal conductivity of the concrete (namely, cement, water and aggregate) used in its realization, the same should hold for the mortar (namely, cement plus water) used in the construction of energy micropiles. In this study, the preliminary results of an experimental investigation campaign are presented. The experimental campaign includes thermal conductivity and workability tests carried out on mortar samples and on liquid grouts, respectively. Both neat mortar and mortar plus additives, selected among commercial products with the purpose of increasing the thermal conductivity of the material, were used in the experiments. Three commercial, chemical additives, originally developed for different purposes (e.g., to produce thixothropic mortars, or for the heating floor industry), were used. Experimental results showed that all tested additives were beneficial in increasing the thermal conductivity of the material over the entire range of investigated water/cement ratios, as well as in lowering the initial viscosity of the mixtures. The preliminary results also indicated that one of the tested additives seemed more promising than the others for increasing the thermal conductivity of the hardened grout
Computational and experimental study of seismic site effects on Amatrice hill
No full textAmatrice is considered the town symbol of the destructive effects induced by 2016 Central Italy seismic sequence. As a result of the two main shocks (August 24th, M=6.0 and October 30th, M=6.5) the ancient urban area of the municipality, located on a hilly promontory, was heavily damaged. Old buildings, but also renovated and new buildings, suffered many cracks and collapses. Subsoil geological, geophysical and geotechnical data were collected in the area and seismic data were also available. By using and interpreting the subsoil data, a 3D-GIS model was developed, that is the basic geometrical model for SiSeRHMap hybrid-analysis. Several 2D sections crossing the seismic station sites were extracted from this model and analyzed by 2D-FEM numerical approaches. Comparison of numerical results and seismic experimental data allowed to: i) validate the subsoil model used in the simulations; ii) show the significant role of the topographic effects in the area under study; and iii) point out the variability of the 2D numerical results depending on the direction of the analyzed cross-sections
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