Align JV has paused planned construction work on the Colne Valley Viaduct as it carries out “urgent remedial works”.
The contractor, which is formed of Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick, announced the delay in a letter sent to local residents – as first reported by Construction News’ sister magazine New Civil Engineer.
Align JV said the launching girder being used to place prefabricated segments of the viaduct was supposed to start moving over the Grand Union Canal this week – but this has been postponed while remedial works are carried out “inside the viaduct”.
HS2 Ltd has confirmed that the works will involve repeating cable tensioning on the section of the viaduct most recently completed. This will mean drilling out the span’s concrete join.
HS2 said the remedial works started on Monday (19 February) and will continue during the week.
The letter sent to local residents said the works “will involve the breaking out of concrete and this will generate noise”.
It added: “Due to the essential nature of these works we will also need to work during the night for the next two to three days.”
Once complete, the 3.4km viaduct will be the longest rail bridge in the UK and carry HS2 trains from Hillingdon on the outskirts of London, over a series of roads and bodies of water, before it enters the Chiltern tunnels at the M25 in just 40 seconds.
Construction is a huge undertaking involving more than 1,000 precast concrete structures weighing as much as 140 tonnes each, which are being cast on site.
The 700 tonne launching girder places the segments to construct the viaduct alternatively on either side of each of the 56 piers in a cantilever method.
The faces of each segment are match-casted to lock together perfectly with the previous segment, ensuring maximum contact between them to provide greater connectivity and stability. These are then post-tensioned with steel cables that are threaded through the segments.
Align JV had reached the halfway point of the viaduct construction by November 2023.
A spokesperson for HS2 Ltd said: “We need to repeat cable tensioning work on the most recently completed span of the Colne Valley Viaduct. To do this, first we must drill out the span’s concrete join.
“We hope to complete it this week, and then construction work will continue as planned.”
For more information on the construction of Colne Valley Viaduct, read CN’s project report on the scheme here.
Copy of letter from Align JV to local residents
Important information about overnight works on the Colne Valley Viaduct
As you may be aware, the launching girder for the Colne Valley Viaduct has now reached the Grand Union Canal next to Harefield Marina. The girder was due to start moving over the Grand Union Canal this week, however we have had to pause this while urgent remedial works are carried out inside the viaduct.
These works will start today (Monday 19 February) and will involve the breaking out of concrete and this will generate noise. Due to the essential nature of these works we will also need to work during the night for the next 2-3 days.
Please accept our apologies for any inconvenience or discomfort caused by these works and if you have any concerns, or are impacted by these works during the night, we may be able to offer alternative accommodation for the duration of the noisiest works.
Please contact the HS2 Helpdesk on freephone […]
Kind regards
Align Community Engagement Team
