Parts of the 45 year old Yanley Viaduct have become worn, and heavy use by over 19,000 vehicles every day means that maintenance work is needed to prevent further deterioration.
Start date and duration of works
Work starts on Monday 11 August for approximately 23 weeks, though further work will continue underneath the viaduct which won't impact on traffic.
Traffic restrictions on the bypass
Two out of the three lanes on the bypass will be closed to allow the work to be completed safely, leaving only one lane open. Only traffic travelling into Bristol will be allowed onto the bypass during the morning with priority changing by 5.30am to allow this. The priority will change again around 11.30am to allow traffic travelling out of Bristol to use it in the afternoon. The sequence of how we reverse the traffic flows safely is:
- 4.15am - close the bypass
- 5am - open the bypass (for traffic flowing in-bound to Bristol)
- 11.30am - close the bypass
- 12.15pm - open the bypass (traffic flowing out-bound from Bristol)
Traffic diversion routes
Diversions will be in place for traffic that is travelling against the flow of the bypass. Cars coming into North Somerset from Bristol diverted up Clarken Combe and along the B3128, then down Belmont Hill in Wraxall. Heavy goods vehicles coming into North Somerset from Bristol will be diverted away from the bypass onto Beggar Bush Lane to pick up the A369. They can then join the M5 motorway at junction 19 and continue to junction 21 where they can rejoin the A370. The same routes will operate in reverse for vehicles travelling into Bristol from North Somerset. View our diversion route map.
The official diversion route is not through Long Ashton village although we have seen that traffic using this route is causing significant queuing at the junction with Clarken Coombe/Ashton Road. The right of way at this junction is for the diversion route and while we have worked with the parish council to trim back the vegetation to increase visibility, as well as placing no parking cones to increase access to the left turn lane, we are not putting in any additional traffic control (for example roundabout or temporary traffic lights).
Disruption in the area
It is inevitable that there will be an increase in traffic on local roads around the bypass, but we will do all we can to make sure disruption is kept to a minimum.
A 7.5t weight limit will be introduced through Long Ashton, though buses and local delivery vehicles will still have access.
Parking restrictions will be used to keep congested areas of the villages clear during peak times, download our map of parking restrictions in Long Ashton (pdf) and notice of intent (pdf).
Access to Long Ashton park and ride will still be available during the works, though users travelling against the flow and wanting to travel up the bypass from 5-11am will have to follow the diversion route.
Some bus services will be diverted while the works are taking place, for more information view latest bus service changes.
Why the work is needed
The waterproofing layer and expansion joints have become worn, leading to deterioration of the bearings, as well as parts of the steel superstructure and the tops of the reinforced concrete piers next to the expansion joints. If maintenance work isn't carried out and the bearings seized, this could cause the deck to buckle which would cost more to repair.
What the work will involve
Work will involve waterproofing the deck, replacing the deck expansion joints, and afterwards resurfacing the carriageway and painting the steel parapets. The bearings need to be replaced, the steel structures which support the deck need re-painting and repairs are needed to the reinforced concrete pier tops that have deteriorated because of salt water getting in.
What the work will achieve
Once these works are complete, major work to the structure will not be needed again for another 15 years and the structure will remain fit for purpose, carrying large volumes of traffic in and out of the city of Bristol. Although the work will cause disruption for the duration of the scheme, it will mean that all work is carried out at the same time rather than various schemes over the next few years.
How the works will be funded
We have successfully bid for £2m of funding from the Department for Transport's Pinch Point Fund and will be contributing £1.4m.
Reasons for choosing this type of repair and maintenance
We commissioned a detailed inspection of the viaduct structure in 2012 and a special inspection of the bearings in 2013 which showed that work would be needed to maintain the integrity of the structure. We considered trying to repair the failing bearings which would possibly extend their life by five to ten years, but the 'whole life' maintenance costs of doing this are much higher than replacing them now.
Most recent maintenance has included:
- 2006: deck waterproofing and resurfacing
- 2004: bearing replacement
- 2000: expansion joint replacement
Follow @NSC_Yanley on Twitter when the works start for the latest real-time updates.