Queensferry Crossing is the world’s longest three-span cable-stayed bridge and provides a vital transport link over the Forth estuary. Working in consortium, HOCHTIEF delivered the 2.7km road bridge, which features three towers, two approach viaducts and a two-lane motorway with hard shoulders, as well as associated road connections to the north and south of the estuary.
- 2.7km three-span cable-stayed bridge: 3 towers, 2 approach viaducts
- 2 lane motorway
- 5km dual three-lane carriageway
- Junction upgrades
- 150,000t of structural concrete
- 30,000t of steel
- 23,000 miles of cabling
- Utilities diversions
Our alternative proposals for the pier foundations were key to the scheme’s success. While the central tower is based on an existing mid-estuary island, the south and north towers and pier S1 of the southern viaduct are founded on vast seabed concrete bases in permanent steel caissons.
The caissons were built offsite and delivered by barge before being positioned by floating crane, sunk to the seabed and filled with underwater concrete. We set a Guinness World Record in 2013 for the largest continuous underwater concrete pour, pouring 16,869m3 of concrete in a 24-hour non-stop operation. We used a bespoke temporary sheet piled cofferdam to build the central tower foundations, prefabricating the cofferdam offsite and installing it in modular elements to reduce time on the water.
As the estuary included protected wetlands, rare bird habitats, and SSSIs, our on-site environmental team ensured that we safeguarded the marine environment through several initiatives, including protecting porpoises, otters and common terns.
The scheme won several awards, including CEEQUAL Excellent, Considerate Constructors Scheme Gold from 2013 – 2017, a Green Apple Award 2014 and a GO (Government Opportunity) Award, which celebrates excellence and innovation in procurement. Queensferry Crossing opened to traffic in August 2017.