Giant HS2 viaduct deck slide breaks records: Video

Grant Prior 1 week ago
Share

HS2 has released new timelapse footage showing engineers completing the heaviest and longest single-stage viaduct deck slide on the project so far.

The four-day operation – which was completed on Sunday – involved sliding the 4,500 tonne deck across a road and railway line near Wendover in Buckinghamshire.

Stretching for 345m, the Small Dean viaduct is one of 50 major viaducts on the HS2 project.

Its concrete and steel deck was assembled to its full length before the slide began with most of the precast concrete deck slabs installed in advance of the launch. This increased the weight of the slide but will save time during the later stages of the project.

The whole operation was the heaviest and longest slide of a signal-stage viaduct deck on the HS2 project so far. The A413 was reopened at around 8.30pm on Friday, nine hours ahead of schedule.

During the slide, special pads covered in PTFE – a Teflon-like material usually found on the surface of a non-stick frying pan – were used to minimise friction between the deck and the temporary steel bearings on top of each of the piers. A cable system was used to slide the deck forward at speeds of up to 10 metres per hour.

HS2 Ltd Project Manager, Jason Bicknell said: “Small Dean is the longest continuous deck slide on the project and an amazing engineering achievement. But it would not have been possible without the huge amount of preparatory work put in over the last few years and I’d like to thank everyone involved. Two years ago, we set a target to install the deck in summer 2025 and it’s great that we came in ahead of schedule.”

Before the slide could begin, the team spent four years preparing the site, diverting utilities, realigning the road, building the abutments and six piers that support the viaduct and assembling the deck.

With the deck now in position, engineers can begin the challenging job of lowering it by 60cm onto the permanent bearings which will support the full weight of the viaduct. The two-month long operation will see it carefully lowered by 20cm at a time, pier-by pier, until the whole deck settles into its final position.

The viaduct is one of only two places in the Chilterns where the HS2 route will be above ground level, with the underside of the viaduct just 6m above the road, supported by the huge Y-shaped piers.

Like the nearby Wendover Dean viaduct, Small Dean’s enormous deck is made from weathering steel, which naturally ages to a characteristically dark russet finish to echo the natural tones of the surrounding landscape.

Both viaducts have innovative ‘double composite’ structures, with layers of reinforced concrete on the top and bottom to create a much more structurally efficient box-like span which dramatically cuts the amount of embedded carbon in the design.

In a nod to the great railway bridges of the Victorian age, the side of the Small Dean beam features prominent deck stiffeners which help to manage the structural forces while allowing for a more structurally efficient span.

The viaduct is being delivered by HS2 Ltd’s main works contractor, EKFB – a team made up of Eiffage, Kier, Ferrovial Construction and BAM Nuttall – working with their design partner, ASC (a joint venture between Arcadis Setec and COWI). They worked closely with a team from Network Rail to plan and deliver work close to the railway.

Martin Gamble, EKFB’s Senior Project Manager said: “The team at Small Dean Viaduct has worked tirelessly over a number of years to prepare for this momentous event. Through careful planning and by implementing time-saving measures, we’ve accelerated the bridge and support construction, bringing the launch date forward.

“The complexity of the interfaces with the road and railway have provided a real challenge which, with the assistance of Network Rail and Buckinghamshire Council, we have risen to and overcome, while keeping disruption to the surrounding area to a minimum.”

Latest news

Local contractor Castle lands £60m South Shields campus

Work to start this summer on new home for South Tyneside College and South Shields Marine School
3 hours ago

GRAHAM wins £100m deal after safety regulator approval

Dyecoats scheme in Leeds becomes one of first to receive Building Safety Act Gateway 2 green light
1 day ago

London Super Sewer now fully connected

10-year construction programme draws to a close
10 hours ago

McLaren signs off £125m London Bank over-station job

Developer Helical secures funding deal for 8-storey office job
10 hours ago

Work on Labour’s new towns to start by 2029

More than 100 sites put forward for a dozen new town locations
19 hours ago

Unite hails 12 years without a site accident at Battersea

More than 4,000 union members have worked on the redevelopment without a single serious accident
10 hours ago

Housing orders surge offers hope after 5.2% new work fall last year

Housing orders surged 24% in final quarter of 2024 as developers release schemes
1 day ago

McLaren Property gets new Construction Director

Jon Mangham joins from Equans
19 hours ago

BAM Construction suffers £40m loss after Co-op Live setback

Civils business profit surges 24% to £80m
1 day ago

Over 150 jobs axed as J S Wright goes under

Insolvency specialist FRP Advisory goes in at Birmingham M&E specialist
1 day ago

Extra cash found to speed-up safety regulator

Government to spend extra £2m to clear backlog of high rise approvals
1 day ago

Galliford Try lands £63m RAF accommodation deal

Work to start within months at RAF Digby in Lincolnshire
1 day ago

Balfour Beatty wins Trent arched bridge job

Briton Fabricators will build the £13m bridge from prefabricated sections
1 day ago

Goldbeck to build new £50m Cardiff County Hall

German-owned contractor vowing to be a "disrupter in the UK market"
2 days ago

Laing O’Rourke chairman to step down

Ray O'Rourke to take over chair from Sir John Parker
2 days ago

Farrans lands Leeds Bradford Airport phase 2 upgrade

Contractor takes follow-on refurb job after terminal extension
2 days ago

ISG built Bristol housing block to be torn down

Contractor's collapse sinks Bristol flats remediation claim
2 days ago

RSK revenue nears £2bn as losses soar to £132m

Refinancing last summer puts group on course for more growth this year
2 days ago

Bridge design wind error adds £20m to construction costs

Completion of £148m Grantham Southern Relief Road delayed by a year
2 days ago

Rayner pledges extra £350m for social house building

More than 3,000 homes could be built with cash injection
2 days ago

City’s biggest retrofit tower scheme approved

Triple-fronted 70 Gracechurch Street building will rise to 33 storeys
3 days ago

Defibrillator saves worker’s life on Wates site

Machine operator saved after "dying" for 16 minutes on prison job
3 days ago

Funding deal for £125m Camden Roundhouse scheme

Developer Regal set to start 264-bed student scheme
3 days ago

Balfour leadership rejig to focus on three key growth sectors

Divisional CEO trio take lead roles for energy, defence and transport expansion
4 days ago

ABP bidders day for £150m Humber ports pipeline

Nine projects in the pipeline to support automotive and energy transition schemes
3 days ago

Hinkley Point C to create 3,000 jobs as work ramps up

Fitout surge to swell workforce to 15,000 in next 18 months
3 days ago

Hercules sells suction excavator division for £2.4m

Loss making arm sold by labour hire specialist
3 days ago

Foundations complete at HS2 Old Oak Common station

Station base completed using 76,000 cubic metres of concrete and 17,000 tonnes of reinforced steel
3 days ago

Bids invited for £175m consultancy framework

Fusion21 inviting consultants to join latest four-year deal
3 days ago

Regulator pledges to clear 122 project backlog by April

A third of applications failed to meet required standards says building safety regulator
4 days ago

Contractor services