The February update on progress towards the A46 Stoneleigh Junction Improvement Scheme
Overview
A significant project milestone was achieved in January with the lifting and moving of the New A46 Bridge deck into place over the mainline A46. The new Westley Bridge is now nearing closer to completion.
There is currently still a 50-mph speed limit being enforced on the A46 mainline to allow safe working during the construction process. Crucially, this is an aspect of traffic management which will remain in place for the remainder of the works. A 30-mph 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.
The existing A46 was closed to traffic on the 21 and 22 January 2023, which allowed for the new A46 bridge to be moved into place over the A46 mainline. The A46 was reopened to traffic with the new bridge in place.
Stoneleigh Road West closed at the end of the month and will remain closed for 3 weeks to allow crucial works to be completed to tie in the existing Stoneleigh Road to the new alignment.
Progress to Date
Westley Bridge
Preparing to fill the earthworks up to Westley Bridge level
The bridge parapet has now been installed into the previously poured concrete edge beams. Work is being done either side of the bridge to build up the earthworks for the eventual new Stoneleigh Road West. Once at the correct level, the road construction can begin for the carriageway over the bridge. Due to the height of Westley Bridge in relation to the current ground levels, this a fairly extensive exercise. This work can be seen in Figure 1.
It is anticipated that the bridge will be completed at the end of February 2023.
New A46 Bridge
Figure 2 – SPMT lowering bridge deck onto the abutments
The new A46 bridge deck was moved into place during January 2023, which was the project’s most significant milestone on the scheme.
In the weeks prior to the lift, extensive work was carried out to correctly set up the Self-Propelled Modular Transport (SPMT) which is used to lift bridge decks and move them into place. In this case, the SPMT was used to lift the bridge beams from the side of the A46 mainline and move them to sit on the two abutments which were constructed previously. Parts of the bridge deck had already been constructed whilst the deck was sat on the trestles at the side of the A46 mainline. This included the parapet edge beam, the metal parapet and the deck on top of the steel girders to continue, and be completed, whilst preparing for the bridge lift.
After the SPMT was setup and in place, the bridge move took place over the weekend closure of the A46 mainline on 21 and 22 January 2023. Traffic was still able to travel past the closure using the new off/on slip roads, although this was limited to a single lane in both directions.
Figure 3 – New bridge deck now in place over the A46
The SPMT lifted the bridge and carefully moved the deck over the two abutments. Once in the correct position, it was delicately lowered until it sat correctly on both concrete abutments which would then support the weight of the deck. The SPMT was then moved away back to the side of the road where it could be dismantled and demobilised. The A46 opened to traffic fully in the early hours of Sunday 22 January.
There were observation points setup in safe positions across the site to allow both workers and members of the public to view the whole procedure and the whole operation went very well.
Figures 2 and 3 show the SPMT moving the deck into position and then of the final deck in position.
A video of the move can be seen on the project website.
Erection of street furniture
Throughout January, a sub-contractor has been on site to install new aspects of the permanent street furniture. This includes traffic signs, signposts, bollards and street lighting columns, which are a crucial aspect of the permanent works for when the new road alignment is completed. The street lighting column heads (which contain the actual streetlight) have now been fitted across the previously installed lighting columns along Stoneleigh Road West and East. This progress can be seen in figure 4.
Figure 4- Lighting column installation complete on new Stoneleigh Road West
Further Information
Looking ahead, work will continue on Westley Bridge to complete the bridge in order for the final road surface to be laid. This will permit traffic to travel across the bridge as intended. Stoneleigh Road West will be closed to traffic from 30 January to enable construction of the new Dalehouse Lane link to the new Dalehouse Lane roundabout. This will involve building up the surrounding area with earthworks so the carriageway construction can take place
Now that the A46 bridge lift has taken place, there will be a concrete pour of the diaphragm on both sides of the bridge to connect the bridge deck and abutments, making the bridge integral. Once this has been completed, backfilling can then commence to start to construction of the retaining walls which will be used to connect the bridge to the two gyratory that have been previously constructed.
The project is now coming to the final stages of construction and so more work will take place to tie in the new construction to the existing roads. This will result in changes to the traffic flow through the site and will likely involve moving traffic onto the new roads. At a later date, Dalehouse Lane will be closed to allow the tie in work between the existing road and new roads to take place. Diversion routes will be implemented and in effect for all closures.