East Cambridgeshire District Council
Tony Gee & Partners
The Ely southern bypass is a new 1.7-kilometre road arcing around the southern edge of the town.
The project consists of two main structures, a 100-metre rail bridge over two railway lines and a 300-metre viaduct over the River Great Ouse and its floodplains. Across the viaduct is a cantilevered walkway, built of weathering steel, for pedestrians to enjoy views to the spire of Ely Cathedral.
The rail bridge was manufactured in sections at our Lostock facility, delivered to the site by specialist hauliers and pre-built on-site into larger sections of 150 metres in length. The installation of the rail bridge involved lifting these sections into place in three separate lifts of 75 tonnes each. The lifts were undertaken during two weekend railway possessions using a 750-tonne crawler crane.
The installation of the viaduct was completed using a 450-tonne crawler crane, on a floating platform within the river floodplain. The viaduct's structure consists of six spans of twin trapezoidal boxes, which were installed and welded together over a period of six weeks.
A team of up to 14 welders worked to a sequence to allow the bridge to expand and contract while the welding took place. Structural tie bars were installed within the viaduct's concrete piers, built with a 'hook and eye' design to maintain tension at the top. Heavy steel bars, installed at tension, will keep the viaduct flying over the floodplain when it is crossed by numerous HGVs on a daily basis.
The walkway consists of two ramps, which link and transform into a feature walkway over the river, including the viewing platform. This has been a logistically complex project delivered by our experienced project, construction and in-house design teams.