New bridge over the Bosphorus: Oxand entrusted by T Engineering to provide the safety case
The third bridge over the Bosphorus, is a centrepiece of the mega project of Istanbul traffic relief between the two European and Asian banks. Its completion is scheduled for mid-2016.
The bridge was designed by Jean-François KLEIN Bureau of the Geneva-based Design office T Engineering in association with Michel Virlogeux, consultant in France, at the request of ICA (Içtas and Astaldi Insaat SPa), an Italian-Turkish joint venture. T engineering is in charge of the entire mission, from preliminary studies to detailed design and completion of the bridge.
This bridge presents major technical challenges. To allow combined road and rail crossing on one level and on a record span of 1’408 m, it was necessary to optimize the rigidity of the structure by taking advantage of two complementary cabling systems, the conventional suspension and cable-stayed systems.
Therefore, there was a need to provide the Turkish Ministry of Maritime Transport and Communications with a body of evidence that the bridge design would comply with safety requirements, supported by a demonstration that risks that could occur in operation would be of an optimal control level.
T Engineering entrusted this mission to the Swiss subsidiary of Oxand, based in Lausanne. Oxand relied on its experience and tools based on the “Risk Knowledge Builder” methodology to inventory, analyse and evaluate all accidental situations the bridge could encounter in operation, such as: train derailments, explosion or fire resulting from road, rail or maritime transportation of dangerous materials, lightning of the cable system, earthquake, extreme wind, etc.
By performing a risk-based safety case and capitalizing the content in its Simeo™ ERM tool, Oxand provides a set of justifications arguing that all relevant hazards the bridge may encounter have been identified and that suitable measures have been taken for best risk control or mitigation with respect to the fulfilment of the required functions: structural and people safety, availability and durability. As many qualifications as requested by its future operator.
Project cost: € 800 million (estimate)
Total length: 2164 m, central span: 1’408 m
Deck width: 58.50 m
Tower height: 321.90 m