The Third Bosphorus Bridge: A Milestone in Long-span Cable Technology Development and Hybrid Bridges

The Yavuz Sultan Selim Bridge is a high-rigidity suspension bridge, combining stiffening stay cables and suspension cables. It features a 1408 m central span, and supports a railway and a motorway with a 58.5 m wide deck between stiffening stay cable anchorages. The design of the stiffening stay cables for this bridge required several developments to cater for the exceptional needs of the longest and heaviest stay cable in the world. The usual strand grade would not meet the project forces and 1960 MPa strands had to be qualified, for all the anchorage units within the range, up to 151 strands. Such qualification is, however, only the tip of the iceberg as many other tailor-made components had to be developed. Heavy-duty deviators needed to be proof tested for fatigue and wear and were a vitally important part of the design. Long-stroke hydraulic pistons had to be qualified for performance, long-term resistance to corrosion and ageing.