Kijlstra is supplying CSO structures and river outfalls together with large valve chamber’s to framework sewerage contractor NMCNomenca, who are constructing a strategic upgrade of the existing sewer network serving central areas of the historic town, on behalf of Seven Trent Water.
This first phase of the ongoing programme of sewer improvements is valued at £7.6 million and is one of the most extensive and complex sewerage flooding schemes undertaken by Severn Trent and NMCNomenca, as it involves replacing 2.2 kilometres of mainly Victorian sewers through the town centre, reducing the risk of sewer flooding to over 50 properties in the town.
The new design enables the abandonment of four uncontrolled overflow structures, to be replaced by two new screened CSO chambers which will help to improve water quality in the River Leam in high amenity areas.
Seven Trent Water set its supply chain a challenge to achieve 20% efficiencies in the delivery of their AMP5 capital programme. At Leamington, NMCNomenca are managing to achieve this by adopting innovative techniques and materials in the construction of the project.
NMCNomenca Identified that cost and time savings could be achieved by installing precast concrete units in place of the traditional cast in-situ method, NMCNomenca approached Kijlstra at an early stage of the contact to develop bespoke pre-cast options and work with their design team to help manage the process.
Geoff Hancock, site manager for NMCNomenca said “As part of the project we had to construct two river outfalls which can only be accessed by closing off local footpaths and in area where you are mixing concrete close to a river, it can easily pollute. We eliminated this risk.
Following the success of the outfalls NMCNomenca opted for Kijlstra’s pre fabricated CSO structures together with a large valve chamber. By adopting these solutions the time for completing this part of the project was reduced from five to only two weeks using these innovative technologies
“Although a lot of these works were carried out during the winter months when temperatures were too low to undertake normal in-situ construction our programme was unaffected says Mr Hancock. “The quality was also important, these precast products are manufactured in factory conditions so the finish we get would be very difficult to achieve using traditional methods.”
NMCNomenca estimate that the use of Kijlstra pre-cast structures has provided up to 80% programme reductions compared with traditional construction methods. This was achieved by using simple repetitive designs for connections between the precast panels and the in-situ base, ensuring that no shuttering was required during the installation phase.
The project is being undertaken over eight phases and is due for completion in spring 2012.