Meet our bridge-building machine

To build the the Colne Valley Viaduct, an enormous 700 tonne bridge-building machine has been launched on site to lift the giant concrete deck segments that form the viaduct’s arches into position.

Known as a ‘launching girder’, the 160m long bridge-building machine is the only one of its kind in the UK  and  is named ‘Dominique’.

How it works

The huge viaduct project is being led by HS2’s main works contractor Align JV – a team made up of Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick.

The 160m long bridge-building machine is the only one of its kind in the UK and will be used to lift the giant concrete deck segments that form the viaduct’s arches into position. It can launch itself up to 78m onto the next support and can construct two segments of 133 tonnes, simultaneously. Once each segment stage is complete, the machine will inch itself forward into position to build the next stage.

A total of one thousand deck segments will be needed, with each one weighing up to 140 tonnes. To allow for the gentle curves of the viaduct as it crosses the valley, all the segments are slightly different shapes and made on site at a purpose-built temporary factory close to the north abutment.

Why is it called Dominique?

The launching girder is named in memory of Dominique Droniou, a highly valued and experienced engineer who worked for the Bouygues Group for 39 years and sadly died in 2021.

In 2004, working in collaboration with the girder manufacturer Deal in Italy, Dominique designed the launching girder for the construction of the Hong Kong East Tsing Yi Viaduct, and it is the same launching girder we are using today to construct the Colne Valley Viaduct. The launching girder was revolutionary for its time and today is more than capable for handling the gentle curve of the Colne Valley Viaduct.

Quick facts

• It can construct up to an 80m long span
• With minimum support spacing it can also erect 45m spans
• It’s small vertical clearance means it can pass under overhead powerlines that cross the viaduct
• The viaduct segments can be hung on its trusses, making it easy for end span construction
• 18m high, 18m wide and 700 tonnes – the equivalent to 55 London buses
• Can lift and erect two 133 tonne segments simultaneously
• At peak rate, 20m of deck can be constructed in one shift
• It is a chine designed and manufactured by specialist Italian company DEAL
• It took 5-6 months to be preassembled and then final assembly started in mid-October 2021
• It was delivered in 49 containers before being assembled

Viaduct construction

The Colne Valley Viaduct is designed to span across multiple terrains and minimise impact to the local environment.

It will be the longest viaduct in the UK, 3.4km crossing the River Colne, the Grand Union Canal, several lakes woodland and roads.

The design celebrates the architecture of engineering and its concrete construction means the viaduct will age gracefully over its 120 year design life.

Find out more about the Colne Valley Viaduct