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EN
In the field of metal construction, cellular beams represent an attractive solution to meeting the various technical and economic constraints, especially for large-span buildings. In particular, they allow components linked to the construction to pass through their openings (ventilation ducts, electrical threads, etc.) and thus contribute to significantly reducing the thickness of the floors. However, the use of such beams requires special attention to comply with the regulations in force, in order to guarantee stability and behavior in line with the challenge of preserving the structures. This article focuses on the analysis of the measures of agreement between experiment and computation programs (strength of materials, Robot structures, and Inflexion-EF) results of the beams with circular cuts in their webs (IPE A 100), supported simply and subjected to a concentrated load. The experimental results show that the vertical displacement resulting from transverse compression is induced by various factors: length, cuts in their webs, location of the load, and stiffening of the beams. The comparison of experimental and theoretical results demonstrates the importance of experimental tests in validating theoretical results.
EN
Exposure of concrete to high temperatures affects its mechanical properties by reducing the compressive strength, bending… etc. Factors reducing these properties have been focused on by several studies over the years, producing conflicting results. This article interested an important factor, that is the type of aggregates. For this, an experimental study on the behavior of concrete based on different types of aggregates: calcareous, siliceous and silico-calcareous subjected to high temperatures. In addition, the particle size distribution of the aggregates was chosen to be almost identical so that the latter does not affect the behavior of the concrete. Aggregates and concrete samples were subjected to a heating/cooling cycle of 300, 600 and 800°C at a speed of 1°C/ min. The mechanical and physical properties of concrete before and after exposure to high temperatures were studied. In addition, a microstructural study using a scanning electron microscope and a mercury porosimeter was performed. Thus, a comparative study between various researches on the mechanical properties of concrete exposed to high temperatures containing different types of aggregates was carried out. The compressive strength test results showed that the concrete based on siliceous aggregates (C-S) has better mechanical performance up to 300°C. However, above 300°C, the compressive strength decreases faster compared to calcareous-based concrete (C-C). According to the mercury porosimeter test, at 600°C, C-SC and C-S concretes have the highest number of pores compared to C-C concretes. The microstructure of concrete at high temperatures was influenced mainly by the aggregate’s types and the paste-aggregate transition zone. This study reinforces the importance of standardizing test procedures related to the properties of concrete in a fire situation so that all the results obtained are reproducible and applicable in other research.
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