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Lean Project Summary

The A585 scheme required cropping concrete piles to the correct level for pile caps and capping beams. Overcasting enabled the removal of laitance and weak concrete, ensuring structural quality. Initial use of the Mr Cropper method, combined with hydraulic breakers due to secant wall arrangements, introduced risks such as HAVS exposure and reinforcement damage, while also depending heavily on equipment and skilled labour.
By applying Lean tools such as Value Stream Mapping and Collaborative Planning, Kier Highways and Flannery Plant Hire introduced the Brextor Milling attachment. This innovation reduced activity duration from 182 to 58 days, eliminated 183 person‑days of HAVS, reduced noise, and improved pile accuracy. The success demonstrated Brextor’s value, aligning with National Highways’ standards and encouraging wider adoption of advanced, safer mechanical methods across the industry.

Lean Project Benefits Summary

The A585 scheme delivered significant benefits by introducing the Brextor Milling attachment. This innovation reduced plant and labour costs, improved health and safety, and minimised the risk of Hand‑Arm Vibration Syndrome (HAVS)—eliminating 183 person‑days of HAVS and reducing noise, in line with National Highways standards.
Project efficiency increased as activity duration fell from 182 days to just 58, saving both time and money, with total savings of £123,400, including a £75,000 reduction in plant‑related costs. The Brextor processed three hard piles and 17 piles per day, operated by only one driver and one banksman, and reduced pile‑breaking duration by 66%. Overall, the project demonstrated improved efficiency, safety, and cost‑effectiveness, while showcasing the benefits of adopting advanced construction technology.

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Lean Construction Development Programme (LCDP) Project

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Problem Solving Strategy (DMAICT)

Define

Construction of concrete piled foundations requires constructing or cropping the piles to the correct level to allow the subsequent construction of pile caps or capping beams. From a technical point of view, it is desirable to cast piles higher than the final level because laitance (impurities that migrate to the top of the pile) and poorly compacted concrete can then be removed, leaving well‑compacted, high‑quality concrete over the full length of the pile.
The pile cropping process is often challenging due to site conditions and can also take considerable time to complete. The challenge is achieving the correct pile level while ensuring concrete quality. Potential impacts include delays and compromised structural integrity if the process is not carried out correctly. Dependencies that need attention include site conditions, equipment availability, and skilled labour to manage the cropping process efficiently.

Measure

The A585 project initially began using the Mr Cropper method to reduce the concrete to the correct “cut‑off” level. However, due to the secant wall arrangement (interlinking piles), we were limited in the depth to which the Mr Cropper could work and therefore still required the use of hydraulic breakers to achieve the final cut‑off level. Current pile cropping methods include breaking, fracturing, or crushing the concrete. These methods, when applied correctly, are effective but not 100% reliable. The Mr Cropper pile‑cropper attachment was initially used to reduce the pile to within 200mm of the cut‑off level (as the cropper is restricted within the secant wall arrangement). This meant 200mm of concrete still had to be broken out using breakers. In extreme cases, this damaged piles and reinforcement.

Analyse

Lean methodologies such as Value Stream Mapping (VSM), Root Cause Analysis (RCA), Production Control, and Collaborative Planning were employed to address issues with traditional pile cropping methods. VSM helped visualise the entire cropping process, identifying inefficiencies and areas for improvement. RCA pinpointed underlying problems, such as the imprecision of hydraulic breakers, the risk of Hand‑Arm Vibration Syndrome (HAVS) from manual trimming, and potential damage to reinforcement. Production Control ensured that the cropping process was systematically managed to meet project timelines, while Collaborative Planning facilitated better coordination among teams to address site‑specific challenges.

Improve

Kier Highways, in collaboration with Flannery Plant Hire, introduced the Brextor Milling attachment at Lodge Lane to mill secant piles. This attachment connects to a standard excavator and processes pile heads in a controlled manner. The milling process begins with a milling disk preparing the pile head. Internal cutters break the core tension, while external cutters break the surface tension. Any remaining concrete between the reinforcement bars is mechanically snipped away, reducing the pile to the required level with 1 cm accuracy. This mechanical process significantly reduces HAVS exposure. Since implementing the Brextor process on the A585, 183 person‑days of HAVS have been eliminated from breaking activities, aligning with National Highways Raising the Bar 24 requirements for mechanical methods. The activity duration has decreased from 182 days to 58 days, reducing noise and meeting National Highways Raising the Bar 19 requirements for noise reduction.

Control

Production control meeting is being held, monitored and recorded. Collaborative planning is being used to ensure no clashes with other disciplines within the reserve work area.

Transfer

Get Involved in Trials – This was the first use of the Brextor on a National Highways scheme, and Flannery Plant Hire together with Kier Highways invited others from the industry to witness the Brextor in action. The aim was to showcase this innovation, which meets National Highways Raising the Bar 24 requirements for mechanical methods and Raising the Bar 19 requirements for noise reduction. By demonstrating the Brextor’s capabilities, the trial highlighted its potential to improve efficiency and safety in pile cropping processes. The event provided an opportunity for industry stakeholders to observe the Brextor’s performance first‑hand, fostering collaboration and encouraging the adoption of advanced technologies in construction projects. This approach not only addressed the technical challenges of traditional methods but also aligned with industry standards for reducing noise and enhancing mechanical efficiency.

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Other Project Benefits

Meeting the needs of all users

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Improving safety, health & wellbeing for all

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Delivering better environmental outcomes

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Sustain a well-maintained and resilient network

Sustain well-maintained & resilient network- Other

Providing fast and reliable journeys

Providing fast and reliable journeys - Other

Achieve efficient delivery

Achieve efficient delivery - Other

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