A6091 Galafoot Bridge: Revised Programme (Oct 2018)
REVISED PROGRAMME: 5th OCTOBER
A6091 GALAFOOT BRIDGE SCHEME TO BE COMPLETED IN TWO PHASES
-EXTENSIVE CONCRETE DAMAGE UNCOVERED-
Amey has agreed to re-programme the current A6091 Galafoot Bridge repair scheme, after consultation with Transport Scotland and local stakeholders.
Current repair work on the Westbound A6091 Galafoot Bridge scheme will be concluded by Friday 9th November 2018
To avoid prolonged disruption to businesses, the local community and other road users - particularly over the busy festive period - a second phase of the scheme, to complete the Eastbound carriageway of Galafoot Bridge, will now commence in February 2019. The exact dates of this work will be published in advance of this scheme.
The initial planned A6091 Galafoot Bridge scheme included the replacement of the road and footpath surfacing, the waterproofing of the bridge deck; deck repairs and an investigation into the condition of the expansion joints. However, once the bridge deck was removed it was discovered there was more extensive deterioration of the concrete sections and underlying steel reinforcement than initially expected and, although the structure remains safe for use, a series of night works were required to safely remove. The construction programme will now be revised to ensure comprehensive repairs are undertaken and to alleviate prolonged disruption to businesses, the local community and other road users during the festive period.
Stuart Wallace, Amey Bridges Manager, said: “These refurbishment works were originally intended to prevent the further deterioration of the bridge structure by repairing defects at an early stage. This work has subsequently uncovered several previously hidden defects that far exceeded expectations and this is the reason for the increase to the construction programme”
Stuart Wallace continued: “The local community has shown incredible patience and understanding with the repair programme to date. Having listened to their concerns, we consider it prudent to avoid further disruption over the busy holiday season. This strategy will also mitigate against the possible impact that winter weather might have on this work”
“Once again, we want to thank road users, businesses and residents for their goodwill, and we will continue to consult with local stakeholders and provide updates on this scheme via our website and social media.”
1. Why do there appear to be few people working on the bridge during day?
Our original programme of work commenced on 5th August 2018 (see below) for ten weeks, to carry out deck repairs, replace the bridge deck waterproofing and road / footpath surfaces on both lanes of the Galafoot bridge.
However, when the carriageway was removed it became apparent that the deterioration to the structure of the bridge was significantly more advanced than could have been predicted. To allow the damaged concrete to be removed quickly and safely works were switched to an overnight programme, which offers the best option to minimise disruption whilst delivering major repairs to the deck concrete and underlying steelwork. This meant having to develop a more complex permanent solution and with additional specialist resource both in terms of manpower, materials and equipment.
From the week commencing 8th Oct 2018 additional resource has been added to this work in line with a new programme of works, i.e. a revised major two-phase repair programme.
As the previous repair work was mostly being undertaken at night there was less visibility of the workforce during the day, but unfortunately with the bridge deck and reinforcing steel exposed there was no option to remove traffic management to allow two lanes to safely operate during the day.
2. Why did the surveys, before the work commenced, not identify the problem?
The condition of any bridge deck is not obvious from the road surfacing above, with the only indicators being deterioration of the surfacing (pot-holing) or from the trial inspection areas we carried out at scheme planning stage. However, these only indicate condition at the locations that are exposed and cannot accurately represent the scale of the problem.
Allowance was made in our programme for some concrete and reinforcing steel repairs to be carried out, but not to the level and extent now experienced. Future allowance has been made for similar deck conditions to be discovered during the 2nd phase programme.
Ground Penetrating Radar technology does exist that could have further informed the condition of the bridge deck without removing the carriageway surfacing but sadly this technology is not yet advanced enough to paint an accurate picture of its condition.
3. Exactly what is wrong with the concrete and steelwork, what has had to be done in the way of additional work?
The breakdown of the bridge deck waterproofing system over much of the surface area has allowed salt saturated water to migrate through to the deck concrete, which has in turn corroded some of the underlying reinforcement over the course of many years, resulting in delamination and bursting of the concrete around it.
The deterioration is deeper and over a larger area than we anticipated as the thickness of the concrete covering the steel was not originally constructed to the required depth, indeed many areas have no concrete covering the steel. As a consequence of the poor original deck concreting works many of the reinforcing bars exposed are corroded and pitted to the point where their strength cannot be fully relied upon and need to be replaced. This has resulted in additional work to remove and recast a large volume of concrete.
4. Exactly when in November will the work finish?
The current programme indicates completion of Phase 1 of the deck repair works by 9th November 2018. However, the final waterproofing and resurfacing elements of this phase are weather dependent.
5. What are the plans for Phase 2 – is it another ten week closure of the other side of the bridge, or will there be more to it?
The Phase 2 works are programmed to commence at the beginning of February 2019 and be completed in 8 Weeks by the end of March 2019; should the Eastbound deck be found to be in a similar poor condition.
6. Is February a realistic start date, given the winter weather conditions at this time of year?
Previous bridge deck refurbishment works have been successfully completed on the Trunk Road Network in the Scottish Borders in February and March and an 8 week timescale commencing early February has been developed to strike a balance between addressing the needs of the structure and minimising disruption to the local community over the busy festive period; with the potential higher risk of weather related delays in December.
ESSENTIAL MAINTENANCE COMMENCES 5th AUGUST (For 10 weeks)
Essential maintenance to the A6091 Galafoot Bridge will commence under phased lane closures, from 9pm on Sunday 5th August for 10 weeks.
Concrete repairs are continuing, as night works, on the A6091 Galafoot Bridge. With the bridge deck lifted it is now clear that the deterioration of the concrete is extensive and extends to a wider of section of the bridge surface than we had hoped. We are intending to extend night works to clear the existing damaged concrete and replace this completely. This work is being done on a rolling basis and further updates will be provided. Our priority is to ensure the safety of the travelling public, but we are working as hard as we can to complete these works to the highest standards to prevent further damage to the bridge going forward.
We are receiving reports that vehicles are ignoring the no entry signs on the B6360 at Abbotsford House, which puts other road users at risk and increases the chance of an incident happening at this location. Police Scotland have been informed and additional signage has been added at this location to ensure that traffic is observing this one-way diversion.
This work will include the replacement of the road and footpath surfacing, the bridge deck waterproofing, and concrete repairs. The expansion joint works will be undertaken at a later date, and this will be subject to investigations to be carried out at the beginning of this phase of works. This work will prevent the deterioration of the bridge structure, by tackling potential issues early and reducing the need for more extensive, and disruptive works, in the future.
This scheme requires a full closure of the eastbound carriageway of the A6091 Galafoot Bridge – travelling from Galashiels to Tweedbank – with a signed diversion route in operation. Westbound traffic will continue to use the bridge as normal.
Eastbound traffic will be diverted via the A7 to B6360 Abbotsford Road towards Tweedbank Roundabout. At Kingsknowe Roundabout traffic will join the eastbound A7 to Abbotsford Road (at Abbotsford House) and travel south to re-join the eastbound A6091 at Tweedbank Roundabout.
Emergency vehicles will use this same diversion route.
The B6360 will operate as a one-way road from A7 Junction 7 to Abbotsford, the home of Sir Walter Scott. The Abbotsford Road is only open to buses and coaches from Tweedbank Roundabout to the Abbotsford visitor centre car park.
PLEASE NOTE: A separate diversion will operate for HGVs and other high-sided vehicles via the A7, A699 and A68.
Night time closures will be required at the start, middle and end of the scheme to allow for the installation and removal of the traffic management system. During these night closures a signed diversion route will be in operation. Eastbound traffic will be diverted via the A7, A699 and A68.
This work has been planned in consultation with Transport Scotland, Traffic Scotland, the emergency services, bus operating companies, community councils, road hauliers, Borders General Hospital and Scottish Borders Council.
Real-time journey information can be obtained by visiting www.trafficscotland.org or via Twitter: @TrafficScotland
To report a problem on the network please visit: http://scottishtrunkroadsse.amey.co.uk/report-a-problem/