Tensartech embankments build solid base for business park sustainability
Prominent landscape features for Nottingham’s new high sustainability Castle College Technology Park and Number 1 Science and Technology Park are the surrounding green embankments. By using a Tensartech earth retaining solution from Tensar International, construction company Morgan Ashurst was able to realise the architect’s design over very weak ground as well as provide the most cost-effective solution and prevent soil from going into landfill by re-using it in construction.
The new three-storey buildings in the £17 million Nottingham Science Park were a competition-winning design by HawkinsBrown and Studio Egret West for developers Blueprint, including landscaped grounds with ponds and reedbeds. The embankments hide the ground floor service and car parking facilities for the buildings, and provide ramps including access to the landscaped gardens which lead to a wetland nature reserve and the river.
The original construction proposal had been to use stone gabions only to face part of the embankments and provide thrust relief for the unrestrained soil mass.
However, the wet floodplain site had a Californian Bearing Ratio (CBR) value of only 1, so was unable to withstand the weight of the proposed stone.
Additionally, the site soil was heavily contaminated by decades of industrial activity, so replacement of the soil with a loadbearing fill would have incurred heavy additional costs for soil disposal as well as the environmental impact of the transport required.
“As the gabion installation would have been potentially very problematic and costly in this location, we decided to consult Tensar,” says Nick Hilton, Morgan Ashurst senior project manager.
“They proposed a Tensartech TR2 solution which used geogrids to reinforce site won spoil, consisting mainly of weak arisings. The original aesthetics were maintained by attaching a 300mm veneer of rock-filled mattress to the steel mesh of the TR2 face instead of a wider traditional gabion structure. The result provided a very sustainable solution which was both time and cost-effective. It also solved the problem of what to do with the site soil.”
On the embankment rear faces adjacent to the open basement car park of one of the buildings, the same Tensartech TR2 system was also used to replace the original vertical stone filled gabion wall and supply thrust relief from the 4 metre-high earth embankment.
The 3.6ha site comprises an Automotive Engineering training centre in partnership with Toyota, designed by HawkinsBrown, and helps link Castle College’s secondary and tertiary education facilities. The adjoining second building was designed by Studio Egret West for office and technology users.
As well as the grassed embankments and ramps leading down to a timber decking pathway in the shape of a series of giant lily pads, sustainability features include a SUDS rainwater drainage scheme with ponds and reedbeds, wood pellet burning boiler and natural cooled water ventilation; sustainable and recycled materials are extensively used in the interior.