An eight-month programme to refurbish one of the largest structures that Essex Highways maintains.
Our impact
8months
Duration of maintenance programme
18,000+
Number of vehicles using the A138 daily
11,000
Number of journeys into Chelmsford during peak morning periods
The four-span Oasis Bridge is one of the largest structures maintained by Essex Highways.
Maintenance overhead
Oasis Bridge carries the A138 Chelmer Road dual carriageway over Springfield Road in Chelmsford, Essex.
The four-span bridge is a key component of the city’s transport network and one of the largest structures maintained by Essex Highways.
The list of maintenance tasks on this project included renewal of expansion joints and bearings, and repairs to its concrete abutments.
In addition, new safety barriers were to be installed and the whole bridge waterproofed and resurfaced to increase the likely interval before further maintenance might be required.
Balancing act: Vehicle movements are restricted to protect wildlife including over-wintering as well as nesting birds.
The scaffolding structure had to stand free of the bridge.
Floating world
Scaffolding was needed to create a working platform where the revetment meets the underside of the bridge to enable the team to work on the bearing pads.
The design was a work of art. A complex, freestanding framework with a 32 tonne counterweight, enabled the whole platform to be erected without being tied to the bridge.
Bridge of high pressure
Replacing the bridge bearings required low impact methods.
In this case, Jackson employed hydro-demolition techniques, using high pressure water with an abrasive to remove deteriorated materials (mainly concrete, asphalt, and grout) and leave the way clear for pad replacement.
The water used in the cleaning process had to be piped from the platform and collected in tanks at road level, then shipped for appropriate treatment.
As part of the work, new inspection platforms were installed under the bridge to improve engineer’s access for future surveys.
The scheme was particularly challenging due to the limited working area and close proximity to utility services.
The bridge deck was re-waterproofed to provide future protection from the weather.
Top deck
On the topside of the bridge a team removed the old road surface, saving as much of the under surface as possible, before installing a waterproofing layer under the final road surface.
A key part of the project was the installation of vehicle restraint barriers to protect the bridge parapet and piers. These measures contribute greatly to the general safety of the structure and add value to the investment by increasing longevity.
Bridge works above and below the structure were comprehensive in scope making it sound and fit for the future, as Chelmsford continues to grow as a regional centre.
The works ran smoothly throughout and the team kept road closures to a bare minimum with overnight road closures over the bridge only while the bridge was jacked during bearing replacement works.
