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Traffic Wales information line 0300 123 1213
The Welsh Government’s traffic information service for motorways and trunk roads in Wales

A55 J19 - Glan Conwy Viaduct - Expansion joint renewal (FAQs)


The large expansion joints on the bridge are very worn and must be replaced urgently to avoid the need for an unplanned closure of the A55. 

It is estimated that over 370,000,000 vehicles have passed over these bridge joints since the opening of the viaduct in 1991.

The large expansion joints at the eastern end of the bridge which spans across Junction 19 are worn out and must be replaced. The joint on the east bound side of the bridge is very worn and must be replaced urgently to avoid the need for an unplanned closure of the A55. 

The joints are made and installed as a single unit spanning the full width of the carriageway. Each carriageway needs to be closed for up to one week whilst the old joint is removed and the new joint is installed. The joints are built in to the ends of the bridge which needs to be locally demolished and rebuilt to install the new joints.

The project is programmed to take 2 weeks. The east bound carriageway joint will be replaced first followed by the west bound carriageway joint. Contractors will be working 24/7 to complete the works on each side as quickly as possible.

The works are programmed to take between 5 and 6 days for each side of the bridge. If the works on the east bound side are finished early the carriageway will be opened immediately to ease the congestion caused by the carriageway closure. 

Most of the time there will be lots of activity although this will hidden behind protective screening. There will also be times when there is little or no activity eg. when concrete is gaining strength and drying out before application of waterproofing.

The quickest and least disruptive option for replacing the joints is to work continuously from start to finish. Reinstating and opening up the works after over-night closures would take longer and be more disruptive.

The traffic management for this project will benefit from the installation of the new traffic control system installed at Junction 19 which is due to be completed in December 2020.

Running the two projects at the same time would also have been too disruptive as each project has very different traffic management needs.

The local roads at junction 19 can be very busy during the morning and evening peak times and are therefore unsuitable for use as diversion routes. Contra-flow cannot be used across the bridge because the carriageway is too narrow to accommodate 2 lanes of traffic and provide a safe working area for Contractors. The only option for diverting traffic is to use the Junction roundabout and slip roads.

Most importantly the work is being carried out in January as this is traditionally the time of year when the least weekday traffic uses this part of the A55.

Contractors will be working 24/7 to complete the works as quickly as possible. Fast setting products which are more expensive will be used. Extra plant and tools will be on hand in case of breakdown. If the weather is cold and inclement the works site will be tented to allow the works to continue. 

The east bound carriageway is to be diverted as 2 lanes through the junction 19 roundabout and slip roads. The absence of a merge from 2 lanes down to 1 lane will significantly reduce queueing and delay time.

Temporary signs will be added to the basic Traffic Management signage to direct road users to stay on the A55 and to advise road users on all connecting routes to expect queues and delays. Temporary VMS signs will be located on both approaches to Junction 19 providing direction, advice and information about delays.

The newly installed traffic signals at junction 19 will be adjusted to balance flows and queues on all legs of the junction 19 roundabout with the aim of minimising the total disruption and congestion on the A55, the A470 and all intersecting local roads. The system will be monitored as the works progress and adjusted as necessary to alleviate congestion.

Significant queueing and delay is expected at peak times especially on the A55 with moderate queueing expected at other times. A Press Release will be issued asking people to avoid travelling via Junction 19 for all but essential purposes especially during peak times and to expect significant delays if they do travel.

This is to allow Contractors room to work safely on the ends of the joints which extend into the central reserve. To minimise disruption this work will be carried out at night when traffic flows are much lighter.

During the day-time works Contractors will be working behind the central reserve barrier next to the live traffic lanes. Traffic speed must be reduced to create a safe working area for the workforce.

The local traffic routes are unsuitable for use as diversion routes when traffic flows are high during the day. Drivers who leave the A55 to avoid queues will be delayed more due to the congestion they cause on local roads. 

The west bound On-slip at Junction 19 is too narrow to accommodate 2 lanes of traffic. West bound through traffic will therefore have to approach the junction and travel through the junction as a single lane. This is expected to cause lengthy queues on the approach to Junction 19 which may extend through Colwyn Bay at peak times. 

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0300 123 1213
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