The construction contract for the multi-billion pound Third Bosphorus Bridge is set to be awarded to an Italian/Turkish consortium with a radical Michel Virlogeux-inspired design.
Virlogeux’s design for the 1.4km long suspension bridge is set to be modelled on New York’s Brooklyn bridge and will feature cable stays to provide extra stiffness.
The cable-stayed/suspension hybrid solution is needed after Virlogeux rejected the original concept design of a double-deck to carry the eight lane highway and twin track railway that will cross it.
Virlogeux hinted that he had fundamentally changed the design, while speaking in Vladivostok last week. “The classic solution is to design a suspension bridge but with a steel truss deck to carry the two levels,” he said. “But the structural depth of such a design is 15m. I didn’t like that at all.
“So I had the deck as a single level, but that made it very wide - around 50m - creating a serious problem around deflection and bending forces. So one solution is to use stiffening cables, like the Brooklyn Bridge,” he said.
“But the decision is not yet formally made so I am not allowed to show too many things,” he said.
Virlogeux was cautious because a formal contract award has not yet been made. But Turkish contractor Ictas has already declared its consortium the winner.
In a statement last week it said that it had won the contract after submitting the bid with the shortest construction period of 10 years, two months, 20 days.
Third Bosphorus Bridge to mirror New York design