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16.27: Fabrication activities and quality aspects of the Third Bosphorus Bridge orthotropic steel deck
Author(s) -
Molinaro Carmine,
Sorge Roberto,
Fiscina Gennaro
Publication year - 2017
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.484
Subject(s) - orthotropic material , deck , quality (philosophy) , welding , bridge (graph theory) , engineering , fabrication , facade , civil engineering , construction engineering , structural engineering , computer science , manufacturing engineering , mechanical engineering , medicine , philosophy , epistemology , finite element method , alternative medicine , pathology
The Third Bosphorus Bridge is the link of two continents, Asia and Europe, joining the two sides of Istanbul, Turkey. With its “hybrid” cable‐stayed/suspended configuration, its 322m A‐shaped towers and its Orthotropic Steel Deck, the widest (59m, 8 lanes of motorway and 2 lanes of railway) and heaviest in the world (each of the 59 segments weighting about 850 Ton, over 50000 Tons total), this is not a common bridge. And, as a consequence, not common are the technical requirements, the reference Norms and Standards and the problems and challenges encountered and tackled during its construction. This statement has proved to be particularly true with regard to the Orthotropic Steel Deck for two reasons: a) the complexity of the fabrication operations, given the difficulty of the Design and the unusual dimensions and weights involved; b) the exceptionally high quality levels to be met in terms of dimension control, surface preparation and welded joints in particular, arising from the adoption of the UNI EN 1090–2 Execution Class EXC4, requiring the EN ISO 5817 level B and the additional quality requirements specified for quality level B+. This paper aims to describe the whole process of the Steel Deck fabrication. Raw material procurement and preparation activities are discussed. Prefabrication activities, showing how each 850 Tons segment is broken up into components to satisfy handling and assembling needs are analysed. The automated and manual welding procedures developed to meet quality and productivity requirements are described. Final segment assembly and coating activities are shown. Last but not least, the QA/QC System put in place is described, showing, where relevant, how the implications arising from UNI EN 1090–2 EXC4 come into play and how they are dealt with.