Vibration and noise aspects play a relevant role in the lifetime and comfort of urban areas and their residents. Among the different sources, the one coming from the rail transit system will play a central concern in the following years due to its sustainability. Ground-borne vibration and noise assessment as well as techniques to mitigate them become key elements of the environmental impact and the global enlargement planned for the railway industry. This paper aims to describe and compare the different mitigation systems existing and reported in literature through a comprehensive state of the art analysis providing the performance of each measure. First, an introduction to the ground-borne vibration and noise generated from the wheel-rail contact and its propagation through the transmission path is presented. Then, the impact and the different ways of evaluating and assessing these effects are presented, and the insertion loss indicator is introduced. Next, the different mitigation measures at different levels (vehicle, track, transmission path and receiver) are discussed by describing their possible application and their efficiency in terms of insertion loss. Finally, a summary with inputs of how it is possible to address the future of mitigation systems is reported.
Abstract. This paper describes the analysis of a wind turbine and support structure subject to simulated hurricane wind fields. The hurricane wind fields, which result from a large eddy simulation of a hurricane, exhibit features such as very high gust factors (>1.7), rapid direction changes (30∘ in 30 s), and substantial veer. Wind fields including these features have not previously been used in an analysis of a wind turbine, and their effect on structural loads may be an important driver of enhanced design considerations. With a focus on blade root loads and tower base loads, the simulations show that these features of hurricane wind fields can lead to loads that are substantially in excess of those that would be predicted if wind fields with equally high mean wind speeds but without the associated direction change and veer were used in the analysis. This result, if further verified for a range of hurricane and tropical storm simulations, should provide an impetus for revisiting design standards.
As required by regulations, Finite Element Analyses (FEA) can be used to investigate the behavior of joints which might be complex to design due to the presence of geometrical and material discontinuities. The static behavior of such problems is mesh dependent, thus these results must be calibrated by using laboratory tests or reference data. Once the Finite Element (FE) model is correctly setup, the same settings can be used to study joints for which no reference is available. The present work analyzes the static strength of reinforced T-joints and sheds light on the following aspects: shell elements are a valid alternative to solid modeling; the best combination of element type and mesh density for several configurations is shown; the ultimate static strength of joints can be predicted, as well as when mechanical properties are roughly introduced for some FE topologies. The increase in strength of 12 unreinforced and reinforced (with collar or doubler plate) T-joints subjected to axial brace loading is studied. The present studies are compared with the literature and practical remarks are given in the conclusion section.
Abstract. This paper describes the analysis of a wind turbine and support structure subject to simulated hurricane wind fields. The hurricane wind fields, which result from a Large Eddy Simulation of a hurricane, exhibit features such as very high gust factors (> 1.7), rapid direction changes (30° in 30 sec) and substantial veer. Wind fields including these features have not previously been used in an analysis of a wind turbine and their effect on structural loads may be an important driver of enhanced design considerations. With a focus on blade root loads and tower base loads, the simulations show that these features of hurricane wind fields can lead to loads that are substantially in excess of those that would be predicted were wind fields with equally high mean wind speeds but without associated direction change and veer used in the analysis. This result, if further verified for a range of hurricane and tropical storm simulations, should provide an impetus for revisiting design standards.
The geotechnical construction industry is a major component of the overall construction sector and is strategically important in infrastructure development (transportation, flood and landslide protection, building foundations, waste disposal). Although industry and research in the overall construction sector have been investing significantly in recent years to produce innovative low-carbon technologies, little innovation has been created in geotechnical construction industry, which is lagging behind other construction industry sectors. This paper discusses the interplay between low-carbon geotechnical engineering and unsaturated soil mechanics based on the research carried out within the project TERRE (Marie Skłodowska-Curie Innovative Training Networks funded by the European Commission, 2015-2019,H2020-MSCA-ITN-2015-675762).
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