- Publication no: ABC2017-080-17
- Published: 21 April 2017
The very long spans (over 600 m) have been traditionally dedicated to suspension bridges, but during the two last decades the cable-stayed bridges technology has spectacularly grown.
The first major long span cable-stayed bridge was the Normandy Bridge in 1995, overpassing with 856m by more than 250 ²m the previous maximum main span length. After this significant step a second remarkable structure, the Russky Island Bridge in Vladivostok, was built in 2012. Its 1.104 m long main span is today’s world record for a cable-stayed bridge. More compact parallel strand cables with sophisticated installation methods, allowing works to take place under extreme weather conditions, were implemented for these bridges. Furthermore, the longest stay cables installed on the central span were equipped with smart dampers able to adapt their viscosity to vibration mode.
Recently a third cable-stayed structure, the Yavuz Sultan Selim Bridge (3rd Bosphorus Bridge) in Istanbul, was completed in August 2016. Several characteristics of this bridge are exceptional. It is a high rigidity suspension bridge, combining stiffening stay cables and suspension cables. Its 1.408 m central span today’s world record span, supporting at the same time a railway and a motorway with a 59 m wide deck and its world longest PSS cable make this bridge a technical masterpiece.
This evolution of the cable-stayed bridges toward larger crossings, both in term of span length and loading, has required constant developments in the cable-stayed technology for longer cables and higher capacity.
This article, after a description of the three reference structures in the field of very large spans, presents the evolution of the cable-stay system. In particular are presented major technical changes made necessary by each of these bridges such as the cable capacity, resistance to fatigue, aerodynamic behaviour, damping devices, sustainability, installation, maintenance operations and monitoring.