Construction — EMEA — Great Britain — Bridges
The Queensferry Crossing Bridge in Scotland : DSI ’ s Strand Post-Tensioning Systems ensure Long-Term Connection
The existing Forth Road Bridge built in 1964 near Edinburgh in Scotland is an important road connection across the Firth of Forth – the Forth River Estuary into the North Sea . The 2.5km long suspension bridge was originally planned for 11 Million vehicles per year ; however , it is now being used by approximately 24 Million vehicles per year .
Photos reprinted courtesy of Transport Scotland , Great Britain
That is why the new Queensferry Crossing Bridge is being built parallel to the Forth Road Bridge and to the railway bridge that was opened in 1890 . Once completed , the 2.7km long bridge will accommodate the M 90 Motorway on 4 lanes and will be the world ’ s longest stay cable bridge with 3 pylons . Each of the 3 pylons is 207m high .
The individual spans of the 2,055.50m long stay cable bridge measure 104m , 223m , 650m , 650m , 223m , 104m and 101.5m . The 180,000t composite bridge deck is made up of 110 single box precast segments , each 16.2m long . The cast in-situ North Approach Viaduct consists of 12 single box segments with a total length of 145.80m and approx . 60m long pier tables on each of the pylons . In total , 150,000t of concrete and 30,000t of steel are used for the bridge .
To prestress the bridge deck and the central tower , DSI supplied internal Type SUSPA Systems bonded Post-Tensioning Systems . The main part of the work was carried out in prefabrication sheds on site , where the prefabricated tendons were installed as transverse prestressing into the precast concrete segments . The prestressed segments were then lifted using a cable system .
The designer also used the DSI Post- Tensioning System to provide the proper connection between the individual segments of the central pylon . This was achieved by inserting transverse and longitudinal tendons through the pylon and anchoring them inside the box girder .
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