A concrete joint on the HS2 Colne Valley viaduct is being drilled out this week after two giant segments on the crossing were misaligned.

Main contractor Align JV – made up of Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitzpatrick – started remedial work on Monday and hopes to get back on on track with the planned construction schedule next week.

The 3.4km viaduct will be the longest railway bridge in the UK and so far 700 of the 1,000 precast deck segments required to complete the superstructure have been erected.

The segments – which weigh between 60 to 140 tonnes – are put into place with a 700 tonne launching girder using the balanced cantilever method.

The cantilever is constructed using precast deck segments that are erected either side of the pier with each span tightened into place with internal steel cables.

The final 20cm join is then filled in with concrete.

HS2 confirmed the latest concrete join will need to be drilled out before the segments are realigned and the cable retightened.

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. Work began on 19 February. We hope to complete it this week, and then construction work will continue as planned.”