Media 07/10/2013 Engineering News
Contact Julie Worman Communications Officer Skype: csl.julie.worman 0113 815 0015 PRESS RELEASE: Spencer wins contract for vital work on Humber Bridge Specialist engineering business Spencer Group has won another contract on the Humber Bridge, this time to replace critical parts of the iconic structure. The £3.9m project is to replace four solid steel "A-frames", which connect the main span bridge deck to the towers at either end of the bridge, and carry out associated work to strengthen the landmark crossing. The A-frames each weigh five tonnes and are below the 1,410-metre main span of the bridge. They have to be replaced because the A-frame bearings, which allow them to move as the bridge contracts and expands with the weather, have become worn over time. The wear and tear has been exacerbated because of the dynamic forces on the giant structure over the 32 years since it was built, including the prevailing westerly wind blowing across the Humber estuary. Expert analysis indicated that complete replacement of the system was necessary and would provide a much improved, lower maintenance solution for the Humber Bridge Board. The contract follows Hull-based Spencer Group winning tenders to project manage an inspection of the suspension cables in 2009 and to use a world-leading gantry system to enable vital main cable dehumidification work to prevent corrosion of the cables in 2010. The latest project is complex and will be carried out in cramped areas below the carriageway. Scheduled to last for a year, it will require Spencer, working with sub-contractors, to erect scaffolding to create an expanded, uncluttered working area underneath the bridge deck before the main works can begin. Spencer are applying a design solution developed by leading international engineering consultants, ARUP. It will involve Spencer fitting two so-called "wind shoes", which are designed to absorb wind loading on the bridge deck and reduce the associated loads on the new bearing system. Spencer-designed temporary, hydraulically-operated, load-bearing "arms" will be installed to enable the A-frames to be dismantled and removed, before the permanent solution is put in place, to precision engineering standards, thereby minimising the load pressure on a critical part of the structure. Concrete strengthening work will also be carried out. Within the project price Spencer will take the opportunity to replace four outdated, high- maintenance oil-filled transformers, which enable power and lighting systems on the bridge,  with modern, air-cooled units, thereby mitigating the maintenance costs for the bridge board. Spencer Group Project Director Jim Mawson said: "The Humber Bridge is such an iconic landmark and famous world-wide, so this is very prestigious project for us, especially as the company began in Hull and we have our headquarters in the city. "We are very proud of the fact that the Humber Bridge Board has selected us for this important project that ensures this magnificent landmark remains structurally sound for many, many generations into the future. "This is another example of us taking on a complex and challenging job that other companies would perceive to be risky. We've got the people, the experience and the capability within the business to be quite comfortable with it. We're accepting risk based on the fact that we have the team and the expertise to support this contract and meet and, indeed, exceed the client's requirements." Spencer is working with a number of sub-contractors on the project, including ESL of Hull, which is carrying out the strip-out works; scaffolders Harsco, of Immingham; electrical contractors Pennine Control Systems, of Huddersfield; and steel fabricators Allerton Steel, of Northallerton. At its peak up to 30 Spencer workers and sub-contractors will be on the project. The  contract reinforces Spencer Group's reputation for complex, high-level bridge works. It has used its trademarked gantry system, the Cable Crawler, to enable vital dehumidification work to prevent corrosion of cables on the Humber, Severn and Forth Road suspension bridges, as well as the Alvsborg Bridge in Sweden. Recently it was appointed to carry out the largest retro-fitted bridge dehumidification project ever undertaken worldwide. The work will be carried out on the East Bridge in Denmark, the third largest suspension bridge in the world and part of the mammoth 18km Storebaelt (Great Belt Bridge), linking the eastern and western parts of the country. The Humber Bridge Board has announced the works will require the closure of the nearside lane in both directions for up to 40 weeks from the end of October 2013. This is necessary to reduce the load on the structure whilst the work is carried out and to enable safe access to the working areas. Spencer Group Project Managers Daniel Smith, left, and Joe Bennett examine the project plans below the main span of the landmark Humber Bridge.