Graham is main contractor on the Chelmsford East Beaulieu radial distributor road. The £16.8m phase three contract comprises a new road bridge over the Great Eastern Main Line railway.
The project provides a road link between the A130 Essex Regiment Way and the Beaulieu and Channels housing developments, on the west side of the railway tracks, to the A12 Boreham interchange on the east side.
The new Beaulieu rail bridge will be a 161-metre long three-span structure of composite weathering steel fabricated plate girders on in-situ reinforced concrete column abutments and piers. The bridge will have reinforced concrete pile caps and bored cast insitu reinforced concrete piles. The superstructure is being built on site, but on adjacent land offline. It will then be wheeled and jacked in to place using self-propelled modular transporters.
Among the machinery on the project is a selection of hydraulic pile croppers from National Pile Croppers (NPC). These have been used to crop a variety of piles of various diameters efficiently, productively and safely. “The pile croppers are mounted on a 360o excavator and have proved their versatility and effectiveness on all facets of the scheme they have been used on. When lowered onto the concrete pile, the hydraulic system operates the jaw(s) which allows the pile cropper to cut a de-bonded pile and cause the concrete to break away leaving a horizontal finish as a result. In doing this the chisels penetrate in a precise direction up to the rebar to make the fracture,” explained National Pile Cropper sales manager Danny Imlach.
“The work initially involved cropping forty 1,040mm piles using the largest member of the National Pile Cropper arsenal, Quadzilla. This beast of a machine has enabled the contractor to meet its deadline, and has impressed with the speed and quality of the work. The way the cropper works has also enabled the company to recycle the concrete from the cropped pile,” Danny Imlach added.
The NPC pile cropper works with a hydraulic connection between the excavator and the pile cropper via quick release fittings on excavators to both flow and return being required with pressures ranging from 150bar to 275bar. The excavator lifts the pile cropper over the pile and addresses the pile cut-off level where a complete horizontal fracture is made. The chisels penetrate horizontally up to the re-bar to make the fracture. On bonded piles the chisels will then penetrate further, and due to the shape of the chisels and the reaction forces of the rebar, the concrete breaks into pieces and can be lifted off the pile.
“It’s been pretty impressive seeing the Quadzilla and now the Quads in operation; the entire process has impressed everyone who has witnessed it,” he said.
Work on the Chelmsford East Beaulieu S278 (RDR Phase 3) project is expected to complete in spring 2023.
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