The March update on progress towards the A46 Stoneleigh Junction Improvement Scheme.
Overview
During February, construction work has continued in a variety of key areas, most noticeably Westley and new A46 bridges; the new Stoneleigh Road West dual carriageway; northbound off slip, and the new Stoneleigh Road East. The new southbound off slip opened to traffic on the 7 February with a temporary arrangement. This allowed the closure of the original southbound off slip in order to commence the critical work on the East abutment of the new A46 bridge. The temporary speed limit on the A46 remains in place at 50mph, which allows a safe working area and a larger space between the road users and the site construction operations.
Progress to Date
Southbound Off Slip Opening to Traffic
Early in February and following completion of drainage works and laying of the final road surfacing, the new southbound off slip was tied into the existing A46 mainline. Once the off slip was surfaced, lined with road markings and new crash barriers erected, the slip road opened up to live traffic on Monday 7 February. Figure 1 shows a section of the completed slip road. However, work is not quite finished in this area, and it will be necessary to return to complete small amounts of work and correct defects.
Following this, the existing off slip was decommissioned and closed to public traffic. The new southbound off slip is reduced to one lane using traffic management, in order to keep a safe distance between vehicles and workers on site. There is new give way at the top of the off slip, to turn left or right onto Stoneleigh Road.
Northbound Off Slip Embankment Works
The construction of the earthworks for the new northbound off slip embankment is now nearing completion. This can be seen in Figure 2. This involved constructing a new embankment to allow for a realignment of the slip road to enable it to join the eventual roundabout gyratory. Shortly after the earthworks are complete, work will continue to topsoil the embankment and drainage and road construction operations will commence.
Westley Bridge
During February, concrete blinding was poured for the bases of the bridge wingwalls, and then later concrete was cast in the wingwalls. This can be seen in Figure 3 below. Work also finished backfilling the excavation and this was to allow further adjustments to the temporary works to enable the construction of the abutments to continue.
Stoneleigh Road East
With the opening of the new southbound off slip road, work is continuing the realignment of Stoneleigh Road East from the existing road up to the new gyratory. Sections of the footway on the northern side have been partially surfaced and other sections of footway construction are currently underway.
The swale which sits between the new road and existing road has largely been completed and topsoiled. This swale forms part of the highway drainage treatment in this area and will eventually be seeded with plants capable of treating highways water to remove pollutants. This swale can be seen in Figure 4.
In the next period, work will be concentrated around the tie-in point of the new road and the existing Stoneleigh Road East. This will involve laying of kerbs to tie into the existing road and the start of the construction of the road foundations.
New A46 Bridge
The closure of the existing A46 southbound off slip allows construction access to commence work on vegetation clearance and earthwork excavation. This is to enable the construction of a working area to commence building the East abutment of the new A46 bridge. This work was carried out at the beginning of February and towards the end of the month, work began to excavate the foundation of the new bridge on the East side. This will be achieved in a manner similar to the west side through the use of sheet piles to create a “cofferdam” and the foundation work can then begin.
On the West abutment, work has progressed fixing the steel cage of the pad foundation, and the construction of formwork surrounding this cage in preparation of pouring concrete. This can be seen in Figure 5 below. Later in the month, the concrete was poured into the cage to form the pad foundation, ahead of the construction of the abutment which will sit on this foundation. This is the next crucial step of the construction of the bridge foundation on this side.
On the bridge beams, work has progressed in terms of fixing steel reinforcement on the top of the beams, which will eventually form a reinforcement mat that will be cast in concrete, to form the bridge deck. This can be seen in Figure 6 below.
Further Information
In the next period, work to the east A46 bridge abutment will continue and will include the completion of the foundation excavation and the pouring of the concrete blinding (in a manner similar to the west side foundation). The west side foundation of the A46 bridge will shortly be progressed with the construction of the steel formwork of the abutment. The northbound off slip will continue to be developed with the beginning of the carriageway construction, to eventually form the wider off slip. Stoneleigh Road East and West will both have work commencing to lay kerbs and develop the road construction by placing capping and subbase before they are eventually surfaced.