Search results for "Launched"

showing 3 items of 3 documents

Analysis of curved incrementally launched box concrete bridges using the Transfer Matrix Method

2007

Incrementally launching technique is today very competitive for the construction of continuous concrete bridges. During construction the static scheme of these bridges varies continuously, with the advance of the deck above piers, producing temporary stresses rather different from those occurring in service. An approach to analyse construction phases of curved incrementally launched bridges is presented for concrete single box girder, using the Transfer Matrix Method. A procedure based on this method, already developed for straight launched bridges, has been extended to curved beams, allowing engineers to estimate the effects of horizontal curvature during the entire launching process. This…

Curved bridgeLaunched bridgeTransfer matriceBox concrete
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Adjustable prestressing for construction stages of incrementally launched bridges

2014

Incrementally launched bridges, which are generally built with the static scheme of a continuous beam on supports, change their scheme several times during launching. In these different configurations, internal forces vary and bending moments of opposite signs occur in the same sections for different positions of deck during advancement. In these bridges, two different kinds of prestressing are necessary: a temporary one during launching and a definitive one in service life. In this study, the possibility of implementing automatic adjustable prestressing for the launching stages is investigated; the launch prestressing is partially supplied by a system which can change the tension value in …

EngineeringEnvironmental EngineeringTension (physics)business.industryLaunchedStructural engineeringContinuous beamDeckconcrete deckSettore ICAR/09 - Tecnica Delle CostruzioniService lifeBending momentprestressingbridgebusinessInternal forcesCivil and Structural Engineeringincremental launching
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La recente riforma della disciplina italiana del subappalto nella prospettiva del bid rigging

2023

L’articolo analizza in chiave critica la disciplina nazionale del subappalto nell’ambito delle gare pubbliche, così come recentemente riformata a seguito di diversi interventi normativi in ottemperanza alla procedura d’infrazione avviata dalla Commissione UE. Stando alla tesi dell’A., l’attuale quadro normativo – caratterizzato dalla quasi totale eliminazione delle limitazioni previgenti (probabilmente anche spingendosi oltre ciò che la Commissione UE ha richiesto) – difetta nel trovare un equo bilanciamento tra il principio della massima partecipazione alla gara, da un lato, e l’esigenza di prevenire e svelare potenziali condotte collusive, dall’altro. La suddetta conclusione, peraltro, ap…

The article critically analyzes the Italian regulation of subcontracting in the context of public tenders as recently amended by several legislative measures in compliance with the infringement procedure launched by the European Commission against Italy. According to the Author’s view the current legislative framework – characterized by the almost overall elimination of the previous limits (probably even going beyond what the European Commission requested) – lacks in finding a fair balance between the principle of the maximum participation in the tender on the one hand and the need to prevent and reveal potential collusive conduct on the other. Furthermore this conclusion is supported by the analysis of the regulation of the causes of exclusion from the tender still too timid in envisaging the optional exclusion of the participants due to anticompetitive conduct.
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