Recycling a roof

The redevelopment of London Bridge station forms part of the Thameslink programme. It is a £600 million, five year long (running to 2018) refurbishment programme aiming to successfully redevelop one of London’s most historic and busy stations. The project is being led by main contractor Costain and Network Rail.

Leading scaffolding contractor XERVON Palmers is in the final stages of a 14-month contract worth around £20 million to deconstruct the train shed roof at the historic station, opening up the station to the sky for the first time in over 100 years.

Crucially, the contract has been completed without the use of major cranes and with all railway operations continuing as normal. The station was still capable of serving its 100,000+ passengers per day and there was no disruption to traffic in the surrounding streets.

Down onto the deck

The huge project included creating a structurally- supportive 18,000 square metre protection deck running the full 70 metres across the station. This incorporated some 10,000 aluminium special access panels, 350 tonnes of temporary steel and a secondary mobile access.

XERVON Palmers’ contract included the safe removal and recycling of the dilapidated, historic, crescent-shaped train shed roof and the creation of a mobile access walkway in the side roofs to remove the roof cladding (with a bespoke access in the central barrel of the site with integral support beams). More than 1,200 tons of steel was removed (all by hand) along with asbestos, polished reinforced glass and rare heritage pre-1880 wrought iron.

The deconstruction sequence ensured that, when each piece was removed, the remaining structure was compliant with the detailed loadings allowed. Each piece was manually removed from site via loading paths created within the protection deck. A great deal of effort went into planning and coordinating the works, managing the logistics and transport to remove and safely dispose of the waste.

The vast London Bridge project adds to XERVON Palmers’ extensive transport scaffolding and access CV, with recent jobs including St. Pancras, Paddington, Waterloo, Waverley and King’s Cross in addition to works on the iconic Forth and Tay bridges.

On reflection

“This has been an exciting and challenging task,” said Ian McFarlane, director for business and project development at XERVON Palmers. “The creation of the protection deck has allowed work above to continue whilst the station operates as normally as possible at ground level. Thanks to our design and execution, commuters would know nothing of the comprehensive work plan which allowed the roof to be deconstructed into manageable sizes and weights. We used all of our experiences from the past to develop this excellent, expert solution.”

David Crabtree, who headed the XERVON Palmers team throughout the London Bridge project, said: “We’re coming to the end of a huge 14-month scaffolding and access job. The design provided has delivered a safe, cost effective, viable and on- budget and on-schedule solution for the whole project – allowing railway and passenger movements to continue as normal.

“The protection deck was a major design solution, created to fit in with Network Rail’s health and safety regulations. As such, before construction began, we carried out extensive drop testing in the design process on a test rig – to prove to Network Rail and Costain the integrity of our protection deck design.

“And it has proved to be an extremely safe and successful set-up – as well as simultaneously providing lateral restraint for the two external walls of the station structure, with a 70-metre tied and braced system, putting loads back into the protection deck with a bracing plane throughout the works.

“It’s been a big, rewarding and successful job for XERVON Palmers, showcasing the depth of talent in the company and our ability to take on complicated jobs like this, on sites of historical importance and at busy operational centres, with the minimum of disruption.”