MANCHESTER AIRPORT FOOTBRIDGE

PROJECTManchester Airport City Footbridge

CLIENTAirport City Limited Partnership

MAIN CONTRACTORBCEGI Construction (UK) Ltd

ARCHITECT & DESIGN ENGINEERROC Consulting / 5Plus Architects clevelandbridge.com

Conceived by Manchester architects 5Plus, the £6m bridge was designed to make a striking addition to the landscape at Airport City Manchester. The 132m long structure features 21,000 decorative perforations along its sides, providing visibility of the carriageway below and casting intricate patterns of light onto the deck.

The complexity of drilling 21,000 perforations of varying sizes into the structural steel web, combined with the tight fabrication tolerances required for this bridge, ruled out many potential bridge manufacturers. Cleveland Bridge was appointed to fabricate and install the bridge, thanks to its expertise, manufacturing resources and track record of complex bridge construction.

Solution

Meticulous fabrication and precise installation by Cleveland Bridge, fulfils architect’s vision for stunning new footbridge

Airport City Manchester is a major development that will provide 5 million sqft of offices, logistics, hotels and advanced manufacturing space over the next 10 to 15 years, with a total development value of £1 billion. Manchester Airport Group is investing significantly in infrastructure at Airport City Manchester. As part of this investment, a new footbridge wasrequired to connect the site directly to rail, bus and tram links, and to provide direct access to and from Wythenshawe and surrounding areas.

Requirement

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Cleveland Bridge fabricated all steel components for the structure, a walkway and access stairs at both ends. The walkway section which included six main girders measuringbetween 25 and 30 metres long, and weighing up to 28 tonnes was to be assembled in the site compound prior to installation. These girders were 2.2m high, with the webs divided into 2.5m panels by stiffener plates along their length. Each panel was perforated with 230 holes of varying sizes, grading from the smallest 35mm holes at the top the largest 80mm holes at bottom, increasing in 5mm increments. The steel used was Cor-Ten weathering grade steel, which develops a rust-like appearance after several years’ exposure to weather, and requires no painting.

Project scope

The six main girders were delivered to site and placed on specially created temporary trestles, 3 girders each side, with temporary restraint systems. The girders were then buttwelded together, meaning the quality of the on-site welding was critical to the integrity of the bridge. The butt welds were ground flush to create an aesthetic finish. The curved girders were joined in pairs by bolted transoms, positioned every 2.5m. The concrete flooring for the deck was also installed across the width of the walkway while the bridge was located on its temporary trestles.

This meant the fully assembled walkway section, weighing 470 tonnes, could be installed onto the piers in one piece. This involved moving it into position over the M56 overnight using two 800-tonne, 20-axle self-propelled modular transporters (SPMTs). After installation the stair sections were installed piece small to complete the overall structure.

The drilling of 21,000 holes of varying sizes in a uniform pattern was an unusual requirement, requiring meticulous fabrication skills. The entire bridge fabrication required extreme precision, since the structure was to be installed on four piers with bearings set in position. Therefore there was zero tolerance for errors, as the alignment of the verticalstiffeners over the bearings had to be extremely accurate.

The tight tolerances meant the fabrication process was reviewed by the client on factory visits, to ensure the accuracy of every detail. The girders were marked, checked, drilled and blasted, with quality checks throughout the process.

Another challenge was the short road possession window, with the M56 being closed for just 12 hours overnight to allow bridge installation. During this short period a trackway had to be laid across the motorway to enable the SPMTs to manoeuvre, since the east and west carriageways were at different heights. In addition, the assembled bridge was braced for movement, so allowance had to be made within the road closure window for removing the ten sets of braces.

Challenges

Cleveland Bridge was able to demonstrate extreme precision in all of its fabrication and installation processes, fulfilling the architect’s brief and meeting the client’s high standards.

The delivery and installation was carried out during the period of Covid-19 lockdown restrictions, which required careful management, close liaison with all parties and rigid adherence to distancing guidelines, all of which were achieved to ensure the safety and wellbeing of site teams and the public.

Despite these challenges, the installation was completed within the short road possessionperiod, and the project was delivered on budget to the client’s complete satisfaction.

Outcomes“ The unique design of the bridge required a steel construction specialist with extensive skill and experience. Cleveland Bridge proved more than equal to the task, working closely with us and deploying the expertise of its engineers and fabricators to ensure the architect’s vision was transformed with extreme accuracy into a truly stunning new structure for this landmark development.” Colin Arnold, Project Manager, BCEGI Construction (UK) Ltd

Cleveland Bridge UK Ltd.Cleveland House, Yarm Road, Darlington, Co. Durham DL1 4DE, UK

T. +44 (0) 1325 381188F. +44 (0) 1325 382320E. info@clevelandbridge.com clevelandbridge.com