New Queensferry Crossing in Scotland - challenges in design and construction

摘要

The new Queensferry Crossing near Edinburgh in Scotland is a cable-stayed bridge with a total length of 2 640 m and three towers up to 210 m high. The two cable supported main spans are 650 m, the two back spans are 223 m and there are approach viaducts at each end of variable spans up to 104 m. The two cable planes are arranged centrally between both carriageways and overlap in the centre of the main spans. This special feature is necessary in order to stabilize the deck and especially the Centre Tower. Unique design features such as having the World's longest pair of free-standing cantilevers with an overall length of 644 m and constructing the works in an exposed location experiencing adverse weather conditions, put very high demands on the engineers and workers involved. It is not only the scale and complexity of the new structure that makes it special for even experienced bridge engineers, but also its proximity to the two existing bridges over the Firth of Forth. The Forth Rail Bridge, which opened in 1890 and was awarded World Heritage Site status in summer 2015, lies alongside the Forth Road Bridge, a large Suspension Bridge opened in 1964. On completion of the Queensferry Crossing these bridges, representing engineering expertise from three different centuries, will form a unique collection of iconic structures. The paper summarizes the challenges in design and construction of this outstanding bridge.