Lanes Group Case Study - Lanes For Drains

Lanes Group PlcMarketing Department

Building 1, 300 Lansdowne Road, Monton, Eccles, Manchester, Greater Manchester, M30 9PJ.

Tel: 0161 788 2266Email: [email protected]

Lanes Group is the largest independent supplier of specialist underground pipeline and utility services in the UK. We have a national network of 23 depots providing a comprehensive range of high quality, innovative utility, drainage and maintenance services for domestic, commercial and public-sector customers.

Lanes Group Case Study

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Challenges and achievements• Sewers in danger of collapse running under residential gardens• Innovative approaches to reduce disruption using patch lining to ‘re-round’ pipes prior to full relining• An example of good practice in close partnership working• Positive response to detailed customer communication

OverviewTogether, Lanes Reline and NMCNomenca used ‘risk vs cost’ solutions to complete this complicated rehabilitation programme for Severn Trent Water. A number of techniques were deployed, including pipe re-rounding, mini dig-downs and full-length lining, to minimise disruption to end-user customers, meet all client targets and complete all works six weeks ahead of schedule.

The project

Background

Severn Trent Water’s £1.2m sewer rehabilitation programme in Scunthorpe involved rehabilitating 4.1 km of grade 4 and 5 sewers which were in danger of collapse. No-dig methods were needed, wherever possible, to minimise traffic and customer disruption. Lengths too severely damaged to allow this technique would be replaced via open trench works. A number of the sewers ran across private land, most notably across a residential estate and on the site of a steel mill operated by TATA Steel.

Right for residents

Sewers at Newland Drive, on a quiet residential estate, ran under private gardens and homes. Initially, it appeared a significant number of open trench repairs would be needed. This would involve disturbing and reinstating gardens, sheds, garages and paved areas, causing severe disruption and distress for residents, many elderly.

Partnership solution – sewer reline


www.lanesfordrains.co.uk

Project: Partnership solution– sewer reline

Client: Severn Trent Water

Sector: Wastewater services: sewer rehabilitation

Location: Scunthorpe

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The project continued

Lanes Reline and NMCNomenca reviewed the data and devised an alternative approach. It was found that patch liners could be installed in collapsed sections of sewer. These would exert enough pressure to push the pipe outwards, re-rounding it sufficiently to allow a full length liner to be inserted. Careful assessment of the risks of this method proved to Severn Trent Water that this was a viable solution.

The plan worked well. Pipe deformation was kept to levels undetectable on post-works CCTV surveys. The technique was used to rehabilitate 76 metres of 375mm diameter surface water sewer in three days, without one building, shed or patio being touched.

Also, risk money set aside for compensation and reinstatement costs could be used to resolve other, previously unidentified, problems within the catchment, providing more benefits for Severn Trent Water and its customers.

At the front of these houses, a 300mm diameter sewer on the kerbline had also been found to be damaged. The original plan was to open repair 44m of the 100m sewer in an open trench, carry out a series of dig-down repairs on the rest and build a 3m-deep manhole. This would have needed a five-week road closure in the run-up to Christmas, which was not ideal.

A single no-dig solution had been preferred, but was considered too great a risk: if the liner had failed, because of the deformities caused by the damage to the sewer, the pipe could have become even more blocked.

The Lanes and NMCNomenca team thought again, and came up with an alternative strategy – carrying out a series of 2-3m dig-down repairs at the worst affected locations, with patch repairs used, as before, to ‘re-round’ less damaged areas. This then allowed a full liner to be installed. The sewer was rehabilitated to the required standards, saving end-user customers from prolonged and unnecessary disruption.

Better for business

Within the same Severn Trent Water scheme, a survey of a 178m, 1500mm x 1200mm concrete box culvert on TATA Steel’s site revealed areas of exposed rebar (reinforcing steel rods). Downstream of it, there was an EA monitoring station capturing surface water drainage data. The outfall was at the foot of a railway embankment on which molten steel was transported, and next to a lime plant that needed 24/7 access.

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The project continued

At the feasibility stage, concrete repair specialists proposed hydro-blasting exposed areas to remove loose concrete, before applying resin cement. Each working area would be sandbagged off from the culvert’s main flows to capture concrete debris, which would be pumped into a settling chamber to avoid polluting the downstream watercourse.

However, the time taken to set up and take down the temporary works for this sub-task was far greater than that needed to carry out the repair. The culvert was also prone to surging flows, so weather conditions would have to be factored in. The team sought a solution which would avoid risk to the workforce, maintain programme deadlines, and minimise the effect of siteworks on TATA Steel.

Lanes Group were able to suggest a technique used before, which allowed resin cement to be applied directly to the affected area, without having to remove loose material. This meant the working area did not have to be isolated, which greatly reduced set-up and take-down time.

NMCNomenca had assessed that the impact of the concrete spalling to the integrity of the culvert was minimal, as the culvert sections had been cast in situ and were more than 600mm thick. The repairs, in terms of current requirements, were largely cosmetic, though would help guarantee the structural integrity of the asset, reducing the risk of further deterioration, and extending its life by 50+ years.

Keeping customers informed

Communication played a significant role in the success of this project. The public’s perception is that sewer rehabilitation caused major disruption. Therefore, concerted efforts were made to communicate clearly and allay customers’ fears.

The team developed bespoke diagrams to show how the reline process would be carried out, including these in letters sent to all affected people, a month in advance and just less than a week in advance. Sign boards at the point of works gave further information. Visits were made to people with specific needs.

The outcome

All works were completed with no unnecessary disruption. Severn Trent Water did not receive a single complaint. This successful project is an example of positive partnership in action: Lanes provided technical capabilities and understanding of no-dig technology, while NMCNomenca ensured that all the client’s targets were met.

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Need for no digPicture showing the line of the sewer, in red, across gardens. Without the trenchless reline solution devised by Lanes, there would have been major disruption.

Lanes Group Case Study - Lanes For Drains

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