Stanton Bonna worked with Kier to develop an offsite linear drainage system on M6 J13 to J15, Stafford with Aqua-Slot^TM Drain.

Key Benefits:

· Rapid Installation

· Reduced waste

· Minimal people interface

· Not weather dependent

Through the early stages of the Highways England M6 J13-15 scheme, Kier Highways engineering and efficiencies teams considered several different options for offsite manufacture, one of the projects developed was the use of a Precast Concrete Aqua-Slot^TM Drain.

Challenge

Early on it became apparent that the largest risk to the use of this innovative product would be the production programme with the scheme needing over 31km, exceeding current manufacturing capacity. This required both Area team, Client and Design team input early in the discussion, allowing a production programme that aligned to the scheme’s needs.

Benefits

· Traditional slip-forming of slot can be problematic, particularly in a live highway environment where concrete delivery is key to success but is often delayed by weather conditions, network congestion and crucially site logistics.

· By using precast, the units can be laid out in advance and laying can commence as soon as a sufficient formation bed is prepared. Laying can continue in most weather conditions.

· Rapid installation achieving outputs in excess of 200m per day per three-person gang

· Factory made units are high quality to tight tolerances and CE marked

· Sump unit and incorporated ironwork means that once the unit is laid there is virtually no other follow up work required

· Reduced waste as this method removes the need for any wet casting or cutting out to form outlets

· Reduced workforce around the operation minimising People Plant Interface

· Ability to change work fronts with minimal impact if blockers are identified or there are unforeseen issues, this provides greater flexibility

· No need for saw cuts as the product naturally features joints minimising HAVS issues

“In the first weeks of laying, outputs were better than expected and we are very pleased with the product. Any reduction in trades and numbers in what is a very constrained environment has to be seen as a positive,” commented Richard French (Project Director M6 13-15).

The Figures

· 14km of Aqua-Slot^TM in Central Reservation

· 17km of Aqua-Slot^TM in the verges

· 55 linear metres per lorry load

· 200m installed per day

· 1.4t unit weight, 2.5m long units

· Rodding access point every 25m

· Bedded on Type 1 and regulating sand layer

· Design support from Kier Highways engineering

· Socket and spigot with gasket to ensure correct jointing and alignment

· EN1433 compliant, D400 & CE Marked