The planing on the North cantilever was completed on schedule yesterday evening. Work has been continuing today on preparing the decks of both cantilevers for the next stage of the resurfacing process. After mechanical and hand tools have been used to remove any remaining material at the kerb interfaces, machines, scrapers and specialist blasting equipment will be used to remove the last of the deck material This provides a clean surface so engineers can inspect the steel deck and welds for cracks or damage.
Depending on the condition of the deck a further blast could be needed using an enclosed short-blasting machine to ensure that the steel deck surface is suitable to accept the waterproofing system.
This process is expected to continue for the remainder of this week, with the waterproofing due to begin early next week.
Additionally, further work has been carried out on the North cantilever expansion joint at the Saltash tower.
This process is expected to continue for the remainder of this week, with the waterproofing due to begin early next week.
We are aware that there were some periods of traffic build up on the bridge yesterday. While the Bridge control room staff took immediate action to change lane priorities to reduce the congestion, unfortunately some traffic chose to remain in the closed lane. This caused delays in changing the lane directions and resolving the queues.
We would ask drivers to follow the overhead signs and leave closed lanes in a safe way as soon as the priorities are changed to enable traffic congestion to be reduced as quickly as possible.
There has also been congestion this afternoon following a two vehicle accident on the bridge. While the Tamar Bridge Recovery vehicle was mobilised immediately ( the incident happened at 2.39pm), it was unable to recover the vehicle because of the damage to the vehicle and the gearbox which was jammed. The police were called and arranged for a specialist flatbed recovery vehicle to attend. The recovery vehicle was on site at 3.53 pm and the lane re-opened after 4.15pm.
We recognise that the build up of traffic on the Saltash side of the bridge has been creating specific issues for people living and working in the town. We have been working with Highways England and Cornwall Council to look at all potential options for mitigating these issues.
One of the causes of the congestion in Saltash is drivers using the Saltash off slip east bound, prior to the tunnel as a short cut rather than the A38 and the Saltash Tunnel. The closure of the North cantilever means that traffic becomes backed up and causes congestion in the centre of Saltash.
We are trialling the use of variable message signing to advise people to use the A38 and the Saltash tunnel to try and address this issue. We will monitor the results of the trial closely and, if it proves effective, will look at how to implement this for the duration of the works.
Once more work has been done on investigating other options to reduce congestion in Saltash, we will be talking with local stakeholders to identify what else can be delivered in the short term.
Some people have been asking why it appears to take so long much longer to resurface the deck of the bridge than resurfacing a main road or motorway.
The simple answer is that our bridge deck surfacing process is very different to standard road construction.
The bridge was last fully resurfaced at the time of the strengthening and widening project in 1999-2001. As part of that project the original concrete deck was replaced by an orthotropic steel deck – this uses steel plate with stiffening ribs underneath. The steel deck is much lighter and stronger than a concrete deck which was essential when the additional cantilevers were added.
Rather than simply putting a layer of tarmac on top of hardcore or concrete as in the case of a road, a specialist asphalt material has to be used to resurface the bridge deck. At only 40-55mm this is much thinner and lighter than the materials used in traditional road construction.
This specialist surface is needed to provide a safe durable running surface for vehicles and also to protect the steel deck from wear and damage due to corrosion and fatigue.
As well as the use of this specialist material, the resurfacing itself is also much more complex than traditional road construction.
There are a number of construction processes that need to be carried in a certain order, similar to a factory production line. The removal of old material has to be undertaken very carefully to avoid damage to the underlying steel deck. Many of the processes require applied materials to become dry or fully cured before the next process can happen and this all adds to the overall time for the works to be completed.
The surfacing has to be sufficiently robust to cope with the number of vehicles using the bridge, the number of heavy goods vehicles, the axle weights of vehicles and environmental factors such as wind or hot and cold temperatures that cause the bridge to move or vibrate.
During the last 20 years the Bridge has carried around 300 million vehicles and we want to make sure that the new surface is robust enough to last for further 20 years.