The April update on progress towards the A46 Stoneleigh Junction Improvement Scheme
Overview
During March, work has progressed on Westley Bridge, the new A46 Bridge, Stoneleigh Road West and Dalehouse Lane.
A 50mph speed limit remains in place on the A46 mainline to allow safe working during the construction of the new A46 Bridge. Crucially, this is an aspect of traffic management which will remain in place for the remainder of the works. A 30mph speed limit is operating on Stoneleigh Road, which runs for the entire site extent and again is anticipated to be in place for the foreseeable future.
Fig. 1 - Westley Bridge transition zone
A new temporary traffic arrangement is in place on Stoneleigh Road West, as the previous road closure has been lifted. This arrangement will be in place until Westley Bridge has been completed. There is also a new temporary traffic arrangement on Dalehouse Lane to accommodate further works in the area, this will be in place until the link to the new roundabout has been completed.
Progress to date
Backfilling either side of the abutments and by the wingwalls has been completed with 6N structural backfill, allowing the next stages of the construction to commence.
Fig 2. - Backfilling operation by Westley Bridge
The carriageway leading up to Westley Bridge has been progressed following the installation of kerbs from the new Stoneleigh Road roundabout, this includes kerbing of a new splitter island.
Scabbling has taken place on the concrete bridge deck which roughens up the surface of the concrete which allows the bridge deck waterproofing to adhere to the surface of the concrete much better. Shot blasting, which is where metal ball bearings are fired against the deck, was also used to achieve the rough concrete surface of the deck.
New A46 Bridge
Fig. 3 - Concrete being poured for new A46 bridge diaphragm
During March, work was done to finalise the formwork and steel rebar installation ahead of the concrete pour of the diaphragms. Both of these pours were completed on separate days during March. This allows the abutments to ‘connect’ to the bridge deck which makes the bridge integral.
The final part of the bridge construction is to construct the four retaining walls, two on each side of the bridge. This will enable to ground to be built up either side of the bridge for the new carriageway to be built to go on to the bridge deck. This is due to be the next stage of construction.
New Dalehouse Lane / Stoneleigh Road West Tie In
Fig. 4 - Concrete pour of new A46 bridge diaphragm complete
New tie in works on Dalehouse Lane has taken place, including surfacing and earthworks to facilitate the eventual tie in between Dalehouse Lane and Stoneleigh Road. This was done during a short closure of the road to allow safe working areas for site personnel.
Existing A46 Bridge
The service trough has been waterproofed and backfilled with LECA (lightweight expanded clay aggregate). Ducting has also been installed for street lighting, water mains and traffic signals. The yellow waterproofing can be seen in Figure 6. This waterproofing will protect the concrete from long term damage caused by water ingress.
Fig. 5 – New Dalehouse Lane tie in surfacing
Further Information
Looking ahead, work will continue on Westley Bridge to complete the bridge and the new carriageway in order for traffic to run over it.
The new A46 bridge retaining walls will soon begin constructed, which will allow for the carriageway to be built over the new A46 bridge. The reinforced earth retaining wall construction is expected to begin shortly and will take a number of weeks.
The existing A46 bridge will also be completed over the coming months, with a new kerbing alignment for the carriageway design and to be more cyclist/pedestrian friendly.
Fig. 6 – Waterproofing being applied to existing A46 Bridge service trough
The remainder of the highway aspects of the scheme will be completed, which will include a number of tie-in points to the existing alignment. This means that some temporary road closures will be required, but these closures will be notified in advance.