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SURVEY PROJECT

A1 Drainage Find & Fix

No-dig remediation in the East Midlands

Working in collaboration with National Highways and their Maintenance & Response contractor Amey, Carnell used trenchless techniques to remove in excess of 700 safety-critical structural defects from the underground piped drainage asset. 

Using a Find & Fix methodology increased the safety and resilience of a 24km stretch of the A1 between Colsterworth and Great Gonerby, while reducing the impact on the customer and maximising the available budget.

The primary methods of achieving this was installing Cured in Place Pipework (CiPP) patches, full-length lining and robotic cutting. These no-dig techniques take place inside the pipe, meaning that the defective sections needn’t be excavated.

Proactive Maintenance

Carnell have designed several survey and remediation packages which can be customised in collaboration with the client to navigate each contract’s commercial / value management challenges.

This Find & Fix scheme followed a ‘Proactive Maintenance’ survey which was completed three weeks prior. Unlike a standard CS 551 Pipework & Chamber Defects Survey which specifies three attempts to remove obstructions from the pipework, Proactive Maintenance means jetting and root cutting ‘until the asset is flowing’ before being camera surveyed.

The survey enabled a programme to be developed by Carnell’s remediation team, with an objective of repairing all structural defects classified as grade 3 and above. This gave an accurate picture of what could be achieved for the budget, providing the client with an idea of timescales and traffic management required.

Find & Fix

Uncertainty remained on what lay beyond the structural defects which had led to surveys being abandoned. Key to the Find & Fix methodology is how, through close liaison with the client, newly discovered safety-critical issues (grade 4 & 5) are reviewed along with the remediation proposals the next day. This meant the solutions could be agreed and implemented on site the following night shift in the same road space booking.

Across the scheme, the no-dig solutions implemented were:

  • 502 CiPP patches installed, ranging from 100mm to 600mm diameter.
  • 1637m of liner installed, ranging from 150mm to 300mm diameter.
  • 142 lateral cuts and 14 picote cuts were made using a robotic cutter.

Drainage DCF

The Data – Check – Fix approach is our asset management methodology which relies on desktop surveys to target areas most at risk and guide the positive interventions.

This removes the need for detailed design which prolongs the process, but also provides reliable survey data on the functioning asset which aids buildability of future schemes

Benefits

Safety
  • No RIDDOR reportable injuries / Zero AFR during more than 150 shifts on the strategic road network.
  • Improved drainage capacity and reduced instances of flooding on the carriageway.
  • Use of SafetyCam showed 98% of vehicles were shown to be adhering to the reduced speed limit in place along the 4km lane closures.
Customer
  • Find & Fix methodology means that reactive works take place alongside planned remediation works, eliminating the requirement for additional TM and lane closures.
  • Liaison with Lincolnshire County Council to share their TM when schemes aligned.
  • Amey shared the TM to carry out barrier and carriageway repairs and arboriculture work.
Delivery

No-dig solutions implemented:

  • 502 CiPP patches installed, ranging from 100mm to 600mm diameter.
  • 1637m of liner installed, ranging from 150mm to 300mm diameter.
  • 142 lateral cuts and 14 picote cuts were made using a robotic cutter in 96 shifts.
  • Additional surveys uncovered c.20% more pipework.
“Just shows with our great working relationship what can be achieved through collaboration.”
AmeyProject Manager