Concrete Step Barrier Improvements on the A 1

Concrete Step Barrier Improvements on the A 1 L 2 B Darren Ruane, Carillion Shaun Todd, Carillion

A 1 L 2 B Scheme Introduction The A 1 Leeming to Barton Improvement scheme will improve safety and journey time reliability between London and major urban centres in the North of England Scotland will result in a continuous motorway standard route between London and Newcastle.

A 1 L 2 B Scheme Introduction • The A 1 Leeming to Barton upgrade will replace the existing dual carriageway with a new three lane motorway. • It will also include the provision of a new Local Access Road alongside the new motorway, improving safety for local traffic from the surrounding communities. • Access to the strategic road network will be via a new grade separated junction at Catterick and an improved junction at Scotch Corner.

Concrete Step Barrier (CSB) • Concrete Step Barrier or CSB are central reservation safety barriers employed to replace traditional steel barriers • Principally constructed by the slipform technique, an almost fully automated process that is capable of providing high and of levels consistent quality and productivity

Quad of Aims Purpose Stakeholder Benefits Deliverables Success Criteria q. Improve efficiency q. Improve productivity q. Increase equipment utilisation q. Optimise labour resource q. Maintain quality of CSB q. Improve on programme q. Reduce price per metre q. Maintain safety standards q. Delivery of programme (on-time or early) q. Identification of accurate process targets q. Best Practice definition q. On-going monitoring and control q. Transferable information to take onto other schemes q. JV Board q. Highways England q. Subcontractors (Extrudakerb) q. Local community q. Road users q. Improvement on programme time q. Improvement on budget q. All deliverables completed and implemented q. No additional costs

The Process

Fishbone Analysis Method People Equipment Additional Set Ups Plan Changes Small Areas Planned Waiting For Operatives Changing Moulds Small Areas Available Output Rates Not Understood Paver Breakdown Small Area Planned Small Areas Always Planned Area Not Available Small Area Planned Wait Setting Out (JV) Wait Setting Out (Extrudakerb) Temperature Not Rising Rain Ground Frost Pins Moved By Other Trades End Of Shift Too Cold Plant Employed For A Shift Membrane Not Available Low CSB Output No Concrete Supply Congestion Of Worksite Obstruction Other Trades Batching Plant Breakdown Inconsistent Demand Poor Concrete Quality Poor Planning Poor Forecast Wagons Waiting Full Team Needed For Start Up Paver Washout/Cleandown Waiting Membrane Installation Single Carriageway Induction And Briefing Moving The Paver/ Jumps Sterile Area Required Waiting Materials Late From Batching Plant Safety Implications Too Few Wagons Longer Installation Time Small Total Daily Volume Environment Materials Small Area Available

Measurement - Data was obtained from • • Operational Work Place Study(s) Compensation Event Quotation Reports Extrudakerb Work Record Sheets Extrudakerb Daily Concrete Record Sheets

Analysis • Data was analysed by mean comparison using excel spreadsheets, graphs and charts • In addition to this, advanced statistical analysis software (SPSS) was used to support or dismiss hypothesises

Analysis Lay Rate The average lay rate per day was 161 linear metres There was a large variation in lay rate per day, analysis showed a standard deviation from the Mean of 76. 7 In addition to increasing efficiency it was also important to address this issue of consistency

Analysis Time on Site • There was a weak positive correlation between total time on site and CSB production • However time on site was not a significant predictor of production

Constraint 1 Concrete Quality

Observational Report Baseline VA NVA Short frequent stoppages accumulate to 25. 65% of optimal work time being wasted Waste 25. 65% 11. 39% 62. 96% 63% of optimum work time the paver was producing the CSB. The remaining 37% of time the paver was not moving

37% Stop Time Break Down 51% of all time wasted during optimal working time is spent adding water to concrete that has become too dry for use

Concrete Quality Measuring 475 concrete wagons spread over 51 days : • 54% of concrete was delivered to dry for use. This concrete must have water added to it on site in order to bring it to an appropriate consistency • Only 23% of concrete deliveries were the correct consistency to be used without onsite alterations

Concrete Quality & Paving Time • A linier regression was used to explore predictive factors of variations in paving time • In the sample of 475 concrete wagons concrete quality had a statistically significant relationship to the time spent on the paver • Concrete being dry increased time on the paver by an average of 7. 39 mins (27. 17%) per concrete wagon compared to concrete of an acceptable quality (p<o. oo 1)

Wait Time & Concrete Quality • Analysis revealed a significant difference in the wait time of concrete that was considered too dry and concrete that was considered acceptable. (p<0. 001) • As wait time increases the likelihood of concrete becoming dry also increases

Rejected Concrete • 64% of all rejected concrete is attributed to the mixture being too dry for use • This number may be significantly higher if concrete wagons did not come with a water source

Concrete Quality Improvement • Concrete quality, specifically concrete being too dry, has a significant effect on productivity • Hope Construction now work closely with Extrudakerb’s site staff to refine the concrete mixture so it is the correct consistency when it arrives on site • To compliment this additional on site checks have been put in place to address concrete quality before it impacts production

Constraint 2 Set-Up Time

Start Time Delays • There is a large variation in start time delays • 49% of start time delay is over 100 min long • The average stat time delay is 176 min

Start Time Delays • There is was strong negative correlation between start time delays and overall CSB production • Significantly less CSB was produced on days that had a longer start time delay

Target Start Time Study Average • An operational work study was undertaken to process map the Work-study set up procedure, identify areas where time saving could be made • The set up procedure took 224 minutes in total

Start Time Study 224 minuets broken down into tasks 10% 37% 63% Waiting for concrete delivery accounted for 37% of start time Setting up the pinless Machine Guidance System was the dominant task in the set up procedure, accounting for 63% of time (running in parallel with 10% of other work)

Set- Up Improvement • A correlational analysis demonstrated a significant positive relationship between the optimum working window and the number of Linear Metres produced • As the optimum working window increases by 1 min the number of Linear Metres produced increases by 0. 47 • If this window was increased by two hours 56 extra Linear Metres would be produced. A 34. 8% improvement • This would bring the total average daily output to 217 Linear Metres

Improvement Summary 1. Start time delays have been rectified through the introduction of a standardised set up procedure. This procedure reduces the set up procedure to under 60 min (saving over 2 hours) 2. To address concrete consistency Hope Construction are working closely with Extrudakerb site staff to refine the concrete mixture without compromising quality so it is the correct consistency when it arrives onsite 3. To compliment this additional on site checks have been put in place to address concrete quality before it impacts production

Transferability • The lessons learnt from this Lean project have a high level of transferability to similar slip form processes such as Surface Water Channel (SWC) production • The knowledge gained form this project is also highly transferable to other central reservation works across Highways England’s supply chain

Transferability Stephen Lee - Group Lean Manager Stephen. lee@extrudakerb. co. uk