The two cantilever beams arrived on site on a lowloader once the road closure was implemented late on Friday night.
Bridge deck span number two arrived on site early Saturday afternoon and was installed into the gap between the already installed spans one and three.
Span five arrived at 5am Sunday morning and was installed just over an hour later. The crane could then begin the de-rigging process.
Once surfacing was completed, the road could be prepared for re-opening. The work area had to be swept before the road-marking crew could begin work to mark out the new temporary traffic lanes.
The excavation started on Friday night, and concrete was being poured on Saturday morning. Once the concrete had set firmly enough, the formwork could be removed, and on Sunday fill material was brought in to raise the ground level above the wall base, and the footpath route was re-created ready for the road to be re-opened on Monday morning.
Four separate areas of road construction were rebuilt during the weekend. The vast majority of Bridge Road carriageway area will be re-surfaced before the end of this project – the top layer of road pavement is called ‘surface course’ and in this case will be 40mm thick.
However, where structural failure of the pavement has been identified because of visible cracking or settlement, these areas are being excavated to nearly 0.5metres deep and entirely reconstructed. Four of these areas were tackled during the road closure.
Our next weekend road closure will take place in the New Year and will be advertised as usual, via signage two weeks in advance and via a news update on the Bridge Road webpage.
Firstly, thank you from the Bridge Road site team for your patience and understanding during these essential closures.
One of the key activities was the demolition of the west side of Countess Wear Flood Relief, with the use of highly pressurised water to remove the concrete that forms part of the structure but leaving the reinforcement within the concrete intact, a process called “hydrodemolition”.
The hydrodemolition involved removing the full depth of the bridge deck over an 800mm wide strip which will allow new steel to be fixed into position alongside the existing steel, facilitating the extension of the structure westwards several metres to cater for the additional traffic lane and the new footpath / cycleway.
Although the bulk of this has been completed, this work is continuing overnight this week. This side profile of the hydro-demolished deck, through the debris netting, was taken at the very start of the hydrodemolition process.
Another key activity was the full reconstruction of road, firstly in areas where structural work had previously taken place, but also in areas that have been identified as reaching the end of their design life and have started to fail.
This operation involves excavating the existing road down to formation depth, placing a layer of well compacted stone, followed by a number of layers of Bituminous material, ready for the road to be trafficked again when the road re-opened on Monday morning. This photo shows an area of carriageway being excavated ready for new material to be laid because this area of the existing road was showing sign of failure.
Due to the number of different layers and cooling time required between the layers it is not possible to do this operation in a single day. This photo shows the paver laying the final parts of the upper base layer and a roller compacting the newly laid material, to the right of the picture you can see the newly installed VRS stanchions being allowed to cure ahead of the road re-opening.
Vehicle restraint systems (VRS), more commonly known as crash barriers, were installed in a number of locations along the length of Bridge Road, with the need to divert services in some locations to facilitate the concreting of the barrier stanchions, following this the barrier’s longitudinal beams had to be fixed in place and the concrete allowed to cure sufficiently ahead of the road opening.
Due to the high volumes of heavy plant and construction traffic throughout Bridge Road, the traffic management had to be altered to allow additional working space in a number of key areas. At the same time, a safe route had to be maintained for pedestrians and cyclists, while also ensuring that the site layout could be accessed by emergency service vehicles, with an ambulance being escorted swiftly through the site at 11am on Saturday.
The weekend programme also included the erection of scaffolding on Countess Wear Bridge ready for the archaeological recording of the listed stone structure, ahead of the partial demolition of the triangular cutwaters in preparation for installing the new Countess Wear Footbridge. This photo shows the bridge parapet which runs roughly down the middle of the photo, with the counter weight water towers on the right hand side, and the working platform over the River Exe on the left hand side of the bridge parapet. This working platform will be used to take the archaeological recordings of the stone work and will also be needed during the demolition of the masonry cut waters.
With work nearing completion on the east side of the carriageway, just south of the canal bridges, contractor Lagan has opted to alter the traffic management layout by swapping traffic to the west side and temporarily diverting pedestrian and cycle traffic onto the road. This has required the removal of kerbing and pedestrian barriers at this location. This arrangement has provided the space required to begin work on the Alphin Brook culvert and Exe Channel Flood Relief Structures on the west side. Once the weekend closure work was completed, the traffic management then had to be altered a final time to ensure the road was once again ready to carry two lanes of live traffic.
In order to minimise disruption to users of the highway, essential work by other contractors has been co-ordinated to take place within the road closure, such as essential road maintenance to the north of the scheme.
Progress report 2 – 26 April to 27 May 2016
The majority of the work on the Countess Wear Relief Bridge in the past month has been hydro-demolition – if you’ve passed the site in this time you may have noticed a blue tanker and a green tent. The operative working inside the green tent holds a high pressure water jetting gun; the water disintegrates the concrete but leaves behind the steel reinforcement. By removing strips in a grid pattern the concrete was broken into chunks.
In the early part of the month, following installation of a temporary steel crash barrier, the existing steel crash barriers on the approaches to the railway bridge were removed. Work has then started on excavating the embankment to the South of the railway line.
Kerbing and services work has continued at the north end of the site, including the removal of the island at the junction with Glasshouse Lane.
Work started this month on the Exe Channel Flood Relief Bridge, which is located between the canal and the railway; although you would hardly notice it from the road – the photo below gives a view from the flood channel to the south.
The eventual plan for the historic Canal Swing Bridge historic bridge is to rotate it by 4.2 degrees, which translates to around 1.6m at the “nose” end. This will allow a better alignment of the road as it passes over it, removing the “kink” on the south side and allowing two lanes of traffic to use this narrow bridge.
This rotation will require new foundations to support the bridge in its new position; this month we undertook some trial openings in order to gauge the space required for a mini piling rig to get in to drive new piles.
Progress report 1 – Start of works to 25 April 2016
The bridge over the river Exe is called Countess Wear Bridge, and houses a healthy population of Soprano Pipistrelle and Daubenton’s bats. The bridge is an ideal habitat for them as in the evenings they can swoop down from their roosts to pluck midge larvae from the surface of the river. As part of the scheme we have provided enhancement in the form of artificial bat roosts. Because this is a historic structure these have been camouflaged carefully to match the stonework of the bridge.
Following this work, the footpath on the Topsham side of Countess Wear Bridge has been removed in preparation for the new kerb line. To enable the widening of the road, the kerb line is being moved further to the East, nearer to the bridge parapets. Much of the work to date has been on diverting and re-laying the services on this side of the road; this is currenyly ongoing. We have a water main, telephone and fibre optic cables, electricity supply for the street lighting, and further telecommunications ducts to fit in a reduced space. The picture below gives an idea of the complexity:
At the North end of Countess Wear Bridge work has started on laying kerbs; however this has necessitated the removal of some buried concrete steps which date from the 1930s. At this time the bridge was significantly widened and the road level raised; these concrete steps stabilise the masonry parapet wall; but unfortunately occupy the space where our new kerb line should be. Therefore the upper part of the concrete steps has been broken out; this won’t affect the parapet wall as the kerbing will be supported by fresh concrete. This has enabled the start of the kerbing work.