1,722,087 research outputs found
On the Assessment and Mitigation of Vortex-Induced-Vibrations of Overhead Electrical Conductors
No full textIn the present work, an extension of the Energy Balance Method (EBM) is investigated, by considering both the dynamic interaction between a conductor and the support system, and the coupling in the dynamic response of two adjacent spans. The presence of dampers in each span to control aeolian vibrations is also taken into account. The modal properties of the line are studied within a rigorous mathematical setting and used as the input to apply the EBM. The parameters that control the dynamics of the structural system are clearly identified, paving the way to the definition of simple yet effective criteria for the design of the mechanical characteristics of the damping devices connected to the line. The proposed procedure allows also to investigate the effects of energy dissipation within flexible supports
On the Seismic Response of Anchoring Elements for Submerged Floating Tunnels
No full textSubmerged Floating Tunnels (SFTs) are interesting modular structures that lend themselves well to the crossing of water bodies. In a widespread design configuration the SFTs retain positive buoyancy and are kept at a fixed depth under the water surface by anchoring devices connected to the seabed. Different technological solutions have been proposed for the anchoring devices. They all share the properties of being slender, axially stiff and very flexible in transverse direction. The positive buoyancy of the SFT is typically tailored such to avoid detensioning (slackening) of the anchoring elements under design loading conditions, e.g. wave and earthquake loading. Whenever the tunnel is located in seismic prone areas, the seismic loading can be the dominant one. The present paper focuses on the local dynamic response of anchoring elements of a proposal for the Messina Strait crossing. The seismic input is modeled according to a suitable power spectral density of the ground acceleration and a reduced-order model of anchoring element is set up according to the classic theory of small-sag cables. The seismic working conditions are assessed with respect to slackening requirements
I processi di comunicazione e partecipazione. Caso di studio: la localizzazione degli impianti di rifiuti
No full textOrganismi geneticamente modificati: quando la scienza incontra la società: relazione introduttiva
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