Search results for "Building"
showing 10 items of 1985 documents
Nanocomposites based on esterified colophony and halloysite clay nanotubes as consolidants for waterlogged archaeological woods
2017
We have designed an innovative protocol for the consolidation of waterlogged archaeological woods by using acetone mixtures of halloysite clay nanotubes and a chemically modified colophony (Rosin). Firstly, we have investigated the thermal properties of HNTs/Rosin nanocomposites, which have been prepared by means of the casting method from acetone. The HNTs content have been systematically changed in order to study the influence of the inorganic filler on the thermal stability and glass transition process of Rosin. We have observed that the thermal properties of the hybrids are affected by the specific HNTs/Rosin interactions. Then, acetone dispersions of HNTs/Rosin composites at variable f…
The role of nanoparticles in decreased washout of underwater concrete
2019
Abstract The paper presents research results of the influence of SiO2 nanoparticles on the washout of underwater concrete and hardened concrete. Based on infrared spectroscopy (FTIR) and thermogravimetric (TGA) analyses of the applied anti-washout admixture (AWA), its chemical structure was determined. A beneficial effect of SiO2 nanoparticles on the reduction of the mix washout was demonstrated and the most probable reason for that phenomenon was given, taking into account the AWA chemical structure and its behaviour in the concrete mix environment. It was found that a dosing method of AWA and nanoparticles to the concrete influenced the washout.
DIFFERENT APPROACHES TO DATE BRICKS FROM HISTORICAL BUILDINGS
2014
Abstract The application of Thermally (TL) and Optically (OSL) Stimulated Luminescence on bricks used as building material has allowed solving an chronological issue in the field of historical building dating. The possibility to use one or more methodologies of dating is closely related to the luminescent and granulometric characteristics of the sample. Using some brick samples collected in the church of Sain Seurin in Bordeaux (France), this paper discusses the implications and the possibility to use different approaches and techniques for dating. With this aim luminescence measurements were performed on both polymineral fine grain and quartz inclusion phases extracted from each brick. For…
Thermal and hygrometric properties of traditional calcarenite stones in the area of Palermo
2017
Il contributo espone le misure di conducibilità termica svolte su tre conci di calcarenite conchiliare e la caratterizzazione igrometrica di uno di essi. I risultati sono confrontati con i dati termici e igrometrici riportati dalle norme tecniche esistenti (UNI 10351, UNI EN ISO 10456, UNI EN 1745). The energy improvement of historic buildings requires detailed knowledge of the thermal and hygrometric properties of traditional materials and components. These data should be collected for specific local contexts, where the features of historic constructions are comparable. For the purpose of developing this tool for the architectural heritage of Palermo, this research focuses on calcarenite s…
Equivalent Non-Linearization of Hysteretic Systems by Means of RPS
2018
BackgroundThe analysis of elastoplastic systems with hardening (Bouc-Wen systems) under stochastic (seismic) loads needs the evaluation of higher order statistics even in the simplest case of normal distributed input. ObjectiveIn this paper, a non-linearization technique is proposed in order to evaluate the moments of any order of the response. MethodThis technique is developed by means of a nonlinear class of systems whose statistics are a priori known. The parameters of such systems can be chosen in such a way that the two systems are equivalent in a wide sense. Result & ConclusionIn the paper, the strategy to obtain the equivalence and the reliability of the results are discussed.
Experimental Investigation of the Shear Response of Precast Steel-Concrete Trussed Beams
2017
The results of an experimental campaign of three-point bending tests on precast composite beams, named hybrid steel-trussed concrete beams (HSTCBs), are provided. HSTCBs are typically constituted by a precast steel truss embedded in a block of concrete cast in place. Two series of specimens were manufactured, designed such that shear failure would occur, and tested under positive and negative bending moment. The experimental results obtained showed that fragile shear failure occurred in almost all cases, evidencing the crisis of the compressed concrete strut involved in the collapse mechanism. Yielding of the steel members provided ductility to the system, especially in those cases in which…
Selective Laser Melting of Ti6Al4V: Effects of Heat Accumulation Phenomena Due to Building Orientation
2022
Titanium alloy Ti6Al4V is one of the most utilized alloys in the field of additive manufacturing due to the excellent combination of mechanical properties, density and good corrosion behavior. These characteristics make the use of this material particularly attractive for additively manufacturing components with complex geometry in sectors such as aeronautics and biomedical. Selective Laser Melting (SLM), by which a component is fabricated by selectively melting of stacked layers of powder using a laser beam, is the one of most promising additive manufacturing technologies for Ti6Al4V alloy. Although this technique offers numerous advantages, it has some critical issues related to the high …
Stressing Sequence for Hanger Replacement of Tied-Arch Bridges with Rigid Bars
2022
The construction of bridges with suspenders, such as cable-stayed or tied-arch bridges, needs deep study of the prestressing forces to be applied to stays or hangers in all stages, depending on the construction technique adopted. In these cases, the main issue is the determination of the initial forces and optimization of the prestressing system in terms of stressing values and sequence. When the bridge is already built and suspenders have to be replaced for maintenance, a different problem has to be faced by the engineer, because the sequence of replacements and the values of the axial stresses depend very much on the service conditions of the bridge and on its historical evolution from co…
Tiled vaults in western Sicily. Originality and continuity of an imported building technique
2012
Abstract The search for alternatives to wood for floorings has led to very interesting experiments on vaulted structures, with diffusion in specific areas. We analyze the Sicilian ones consisting of three layers of tiles with plaster, introduced in the mid-eighteenth century, reinterpreted with the local materials and building culture, with original and ingenious solutions as to seismicity of area. The oldest examples in Palermo date back to the period following the earthquake of 1726, considered a good solution because of their lightness and presumed monolithic structure, able to reduce the pressure on walls. This report is an assessment of this building system, that we found during many r…
Il tempo sospeso del processo interrotto: oltre la rimozione, un futuro per l’incompiuto
2020
Gli esiti di processi edilizi interrotti sono ascrivibili a una categoria di ambiente costruito anomala, che offre un banco di prova importante per la progettazione tecnologica dell’architettura. Infatti, il finalismo incentrato sul conseguimento di obiettivi e la visione lineare del tempo entrano in crisi a fronte di costruzioni il cui ciclo di vita non ha mai preso avvio, irriducibilmente estranee al presente e il cui futuro è controverso. Il fenomeno bipolare dell’incompiuto offre il quadro a interpretazioni dei suoi legami con la variabile tempo, intesa come fattore di trasformazione e perno del progetto architettonico. Considerandone la diffusione e l’evoluzione, si può delineare per l…