Weekend Road Closure Report 24-25 September 2016

Firstly, thank you from the Bridge Road site team for your patience and understanding during these essential closures.

Hydrodemolition mini-rig
Hydrodemolition mini-rig

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.

 

Hydrodemolished deck
Hydrodemolished deck

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.

 

 

Carriageway excavation
Carriageway excavation

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 used by traffic 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.

 

 

Roller compacts newly-laid material
Roller compacts newly-laid material

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 Vehicle Restrain System (VRS) stanchions being allowed to cure ahead of the road re-opening.

 

 

 

VRS barriers
VRS barriers

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.

Countess Wear Bridge parapet
Countess Wear Bridge parapet

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.