The April update on progress towards the A46 Stoneleigh Junction Improvement Scheme.
Overview
During March, progress have been made to the new A46 bridge, Stoneleigh Road East, and the Northbound off slip. Work is nearing completion for the construction of the new A46 bridge deck in its temporary position, with the steel rebar work for the top mat now completed, ready for the concrete pour of the bridge deck. There has also been temporary traffic management at off-peak periods to enable work to commence on Stoneleigh Road East to tie the new road in with the existing Stoneleigh Road.
Progress to Date
Northbound Off Slip Embankment Works
The earthwork build-up for the Northbound off slip embankment has now been completed and can be seen in Figure 1. The earthworks have been set to the correct level, and adequately compacted to ensure stability and reduce long term settlement. Work to install drainage has now begun in the area, with trenches being excavated to lay pipes alongside the newly aligned carriageway. Installation of kerbing work and a dig in the embankment to construct the road foundation will follow.
Westley Bridge
Work has begun to move onto the next stage of the work to the North and South sides of Westley Bridge. This has required adjustment to the temporary sheet piles in the area that hold up the existing ground around the new foundations. Props and beam supports that were originally placed in the excavation have now been removed in preparation for removing the sheet piles. Figure 2 shows the commencement of the removal of the sheet piles on the south side.
On the North side, excavation has taken place around the cofferdam, to allow the removal of props and beam supports. Once complete, formwork will be placed to the foundation walls to continue the walls up to a point where the bridge beams will be able to be installed.
Stoneleigh Road East
The next main area of highways work will be to complete the tie-in of the new road from the eastern gyratory into the existing Stoneleigh Rd East. We have been installing kerbs and capping which forms the first part of the road foundation all the way to wear the new works tie-in to the original road alignment. Figure 3 shows the new road approaching the existing road and footway.
There have been off-peak traffic management on Stoneleigh Road East with 2-way traffic lights, to enable the workforce to work safely at this tie-in point where they are working very closely to the existing road.
In the month ahead, HS2 will be closing the junction of Ashow Road and Birmingham Rd to conduct some investigation works. The Stoneleigh scheme intend to take advantage of this closure to conduct works at the tie-in, most notably the laying of new road surfacing.
New A46 Bridge
Work has been continuing the construction of the east and west abutments, which are critical aspects for the construction programme.
For the East abutment, a large pit has been excavated in which the foundation will be constructed. The support frame for this excavation has been installed in a manner similar to Westley Bridge using props, support beams and sheet piles. A concrete blinding was then cast once the excavation had been completed. This forms a stable platform at the bottom of the pit that serves no structural purpose but enables a clean working platform for the work. Later in this period, reinforcement steel for the foundation base was fixed ahead of the concrete pour. Approximately 150 cubic metres of concrete was installed in this foundation.
The concrete foundation base of the West abutment has been waterproofed with the application of a paint-like liquid which is applied to the concrete surface. This helps protect the concrete from water ingress from the surrounding ground. Once the waterproofing was complete, the excavation was backfilled, and the props removed to allow the continued fixing of steel into the abutment wall.
On the new A46 bridge deck, the fixing of the reinforcement steel has been completed for the top mat, including the arrangement of the parapet edge beams. The bridge is currently awaiting the concrete pour to form the bridge deck.
Figure 4 shows a section of the West abutment with the foundation cast, the reinforcing steel for the wall protruding out of the foundation and the backfill to the foundation. Figure 5 shows the reinforcing steel being fixed in the east abutment.
Further Information
In the coming weeks, the new Stoneleigh Road East will be completed, including the tie-in to the existing Stoneleigh Road. At this point, traffic will then be switched onto the new Stoneleigh Road and the existing Stoneleigh Road will be decommissioned. There will be a concrete pour for the new A46 bridge deck, which will then complete the deck work in its current temporary location.
A concrete pour will commence on the base foundation on the East abutment, as well as another concrete pour for the West abutment wall. Work will also continue erecting formwork for the Westley Bridge abutment walls and the concrete cast for both of them.
Work will also continue work on the Northbound off slip to complete the drainage work and prepare for the construction of the new road alignment. This will include laying new kerbs, constructing the new widened carriageway, and topsoiling the verge.
Elsewhere in the site, construction will start on the new Dalehouse Lane roundabout.