Queensferry Crossing, UK

Scotland’s largest infrastructure project in a generation, the £790m Queensferry Crossing, spanning across the Forth Estuary, is now substantially complete and progressing towards opening to traffic at the end of August 2017. Its form has emerged in a most dramatic way over the last five years. The new Crossing and its approach roads were constructed under a Design and Build Contract for the Employer, Transport Scotland. The Contractor, Forth Crossing Bridge Constructors (FCBC) is a Joint Venture of Hochtief Construction AG, Dragados, American Bridge International and Morrison Construction. Ramboll is the lead partner in the Design Joint Venture carrying out the detailed design of the project, working with Sweco and Leonhardt, Andra und Partner. The crossing comprises a cable-stayed bridge, with an overall length of 2.7 kilometres. At its centre is a three masted cable stayed structure with a unique arrangement of overlapping stay cables. It is be the third bridge across the Forth at Queensferry, alongside the Forth Road Bridge, a 1006m span suspension bridge, completed in 1964, and the Forth Bridge, now designated as a World Heritage Site, which was completed in 1890.

The overall length of the Main Crossing is 2,638 metres with 2,090 metres making up the Cable Stayed Bridge. The superstructure, with two main spans of 650 metres, is supported from the three mono shaft towers. It consists of a steel concrete composite deck formed from a multi cell steel box tub girder with a concrete top slab, reinforced in the longitudinal direction and posttensioned transversely, all suspended from the towers from multi strand stay cables. One of the main challenges on a multi span cable stayed structure is to provide the necessary stiffness to the central towers. The unique solution adopted here is the use of overlapping stays, where six pairs of stays cross over the centre of the bridge and overlap with the adjacent stay array, the first time such a solution is believed to have been used.

Owner: Transport Scotland
Structural Design:Ramboll, Sweco, Leonhardt
Andra and Partner
Contractor:FCBC, Hochtief, American Bridge,
Dragados, Morrison Constructio