16.13: Queensferry crossing cable‐stayed composite bridge

Abstract

ABSTRACTThe Queensferry Crossing near Edinburgh is a road bridge which is constructed as a composite cable‐stayed bridge with two main spans of 650 m and two approach bridges. The main bridge has a width of 40 m and has two skew cable planes with spacing of 16.4 m. The composite deck comprises a single open steel box with a concrete slab on the top.The bridge is designed in accordance with the Eurocodes design standards. The general design approach for the steel deck is based on the Reduced Stress Method in accordance with Eurocode 3 together with finite element (FE) shell method calculations for individual plates and for whole plate panels. The FE shell methods are in accordance with [7] Annex C model 5, which means that the calculation is based on nonlinear material properties and non‐linear geometric behaviour and finally includes plate imperfections.The typical steel deck box is stiffened with longitudinal trough stiffeners and cross bracing frames at a spacing of 4.05 m. Special details are made around the three Towers and the Transition zone between the single steel box in the cable‐stayed span and separated twin boxes on the approach viaducts.The steel structure for the cable‐stayed bridge was fabricated in China and steel segments with a length of 16.2 m were transported to Scotland, where the concrete deck was cast. Afterwards the segments were transported by sea to the bridge site, lifted to their final position and the two segment cables were installed and anchored to the deck and the towers.The Queensferry Crossing is the UK's tallest bridge and has been recognised in the 2016 Guinness World Records for the world's largest freestanding balanced cantilever. The north and south approach bridges were launched with a maximum cantilever span of 104 m.