One of the heaviest loads of 270 tonnes ever to move on UK roads has been delivered safely after a huge operation in Lancashire. The transport of a massive electricity sub-station Quad Booster was organised by National Grid along with Alliance Partners Murphy Group, Siemens and PB Power.
It all started via a more traditional route, by canal barge from Ellesmere Port along the River Ribble to Penwortham, followed by a one mile road trip. The load being too heavy for the M6 Bridge meant that local roads had to be utilised for the short leg to the substation with junctions adapted to accommodate the extended trace of the low loader.
At the site itself a new road had to be constructed rather than using the circulation routes within the existing 400kV sub-station, avoiding the overhead cables of the National Grid. To minimize environmental impact and surface water run-off required a permeable paving solution to form a 6 metre wide roadway, terminating with a 9 metre wide hammerhead for the installation pad itself.
Initial designs favoured a grass paved solution but a guaranteed load capability was needed rather than a reliance on a composite matrix of pre-cast concrete or plastic paver and the binding effect of grass. This was viewed as being an uncertain mix that could be compromised by the extent of the grass cover and ground bearing conditions.
The solution was found in Grasscrete a cast on site reinforced system that unlike pre-cast concrete or plastic pavers doesn’t place any reliance on the binding effect of grass for stability. The customer National Grid revised their design brief to replace grass with a local gravel infill.
Grass Concrete Ltd’s project design team has more than forty years of proven installations. For this project 150mm thick Grasscrete GC2 system was selected along with A393 mesh reinforcement to create a running layer that gained its load bearing capability independently from the grass cover.
To provide the 45kN/m² allowable ground bearing needed for the Grasscrete design on marginal ground conditions a 200mm thick Type 1 sub-base was introduced, this overlaid a 250mm thick 6F/2 material applied to a geo-textile membrane.
The Grasscrete installation was undertaken by Grass Concrete’s own Contracts Division and the 1500 m² was completed within 3 weeks, with full load bearing capability after concrete curing: All in good time for the successful introduction of the Quad Booster.
Bob Howden Managing Director says:
Grasscrete has for 40 years been providing the environmental alternative in paving applications, across a wide range of applications. Not only is this in the UK but throughout our own network of 23 international partners that can now deliver the system into 60 countries. Throughout the years Grasscrete has remained the stand-out reformer amongst grass paving systems with its unique load bearing capability that offers a certainty in design that can’t be matched by other systems.
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