A379 at Shaldon Bridge
A temporary 3 tonne weight restriction has been placed on Shaldon Bridge, which links Shaldon and Teignmouth. The restriction has been implemented following the identification of timber piles within one of the deep water pier caissons where concrete piles were expected.
Exemptions to this weight restriction are in place for emergency service vehicles, local buses (of agreed size) and highway winter maintenance vehicles.
Two-way lights to further reduce the load on the area of concern are also in place while investigations continue.
How long will the weight restriction be in place?
At this stage we do not know how long the weight restriction will be in place for. It will be reviewed as work progresses.
Depending on what further information the investigations find, large-scale civil engineering work may be required to this strategically significant bridge to either strengthen or replace whole sections.
What traffic management is in place?
The temporary traffic signals have reduced the bridge to one lane at the Teignmouth end of the bridge. We have introduced the lights in order to reduce the traffic load imposed on the bridge while investigations continue.
What is the diversion route for vehicles over 3 tonnes?
A diversion route is available for vehicles affected by the three-tonne weight restriction. From Teignmouth, vehicles may take the A381 towards Newton Abbot then the A380 Besigheim Road south to Torbay. Continue along Riviera Way, turning left onto the B3199 Hele Road. Continue along Teignmouth Road and take the A379 to Shaldon. The reverse route also applies.
What has been identified?
The original 1930’s bridge deck is supported on pairs of piers, these piers are themselves supported on four piles. The piles were constructed inside a thick steel caisson that was backfilled with concrete to fully encase the piles.
During the latest routine dive inspection, a hole within the steel caisson was identified with a void behind it where the concrete fill has been partially washed out. As a result, the piles within are now visible and have been identified to be made of timber rather than concrete as shown in the 1930’s record drawings.
The reason why timber piles were installed within this pier foundation is unknown, however, it is currently believed to be an isolated situation.
Timber piles have a lower strength than the equivalent sized concrete piles and are more susceptible to deterioration when exposed to air and water.
As a result of the identified issue and the reduced load bearing capacity of the bridge foundations, we have implemented the three-tonne weight restriction.
The full condition of all the timber piles needs to be assessed until this has been completed and strengthening works have been undertaken the 3 tonne weight restriction will remain in place.
Why wasn’t this identified during the 2001 strengthening scheme?
In 2001 a strengthening scheme was undertaken to remove the 7.5 tonne weight limit. This work included:
- strengthening of deteriorated steel girders spanning between piers
- replacement of the narrow and substandard existing footways
- replacement of the deck to the lifting span.
No work was necessary or undertaken to the 1930’s bridge piers or foundations. New steel columns were installed to support the widened footways.
However, dive inspections were undertaken prior to this work commencing to inspect the condition of the 1930’s bridge substructure. At this time the timber piles were not visible as they were still enclosed in the concrete filled steel caissons. However, another set of piers which had a small hole in the caisson allowed engineer divers to confirm concrete piles were present.
How regularly is the bridge inspected?
The bridge is thoroughly inspected every 6 years as part of a principal inspection. A principal inspection requires the bridge to be thoroughly inspected with inspectors being within touching distance to all elements of the structure.
General inspections are also undertaken every 2 years, these inspections are visual inspections and less detailed than the principal inspection.
Dive inspections also take place on a 6 year interval, the last dive inspections were undertaken in 2012 and 2018.
What are we doing?
A full deep water inspection is underway on the deteriorated pier to ascertain the full condition of the timber piles contained within. This inspection will provide vital information to allow a load assessment to be undertaken.
Both temporary and permanent remedial schemes are being worked up to resolve the defect and ensure full load transfer through the pier can be achieved.
Divers have been working in difficult conditions to achieve the full condition survey, some of the challenges faced are as follows:
- Limited working windows due to the tides (approx. 2 hour windows per tide).
- Poor visibility underwater.
- Poor access to inside of steel caisson to inspect internal piles (cutting of steel and remaining concrete to allow access).
- Removal of bed material from within and around the caisson required.
Can I claim compensation?
There is no legal obligation or express statutory authority that enables us to compensate for increased costs or any financial loss suffered as a result of the traffic management or weight restriction put in place.
While every effort is made to inconvenience the public as little as possible there are times when however regrettable interruptions cannot be avoided.
If you would like any further information please contact our Customer Service Centre on 0345 155 1004.