This Award covers successful UK pipeline renovation projects of any diameter or technique for cables, ducts, culverts, and pipelines for any utility, using trenchless techniques.
Other category finalists can be found here https://www.ukstt.org.uk/2024-finalists/
The finalists for the Renovation Large Project award are:
MCALLISTER BROS LTD / SCSJV (HS2)
Manderville Rd
In the context of the HS2 project, the largest project in Europe, McAllister was contracted to provide sewer mitigation for assets on the route of the Tunnel-Boring-Machine (TBM), each asset was assessed against Thames Water’s (TW) criteria for the Ground-Movement-Assessment (GMA).
In NW London, there were twin-barrel TW syphon sewers crossing directly underneath major rail infrastructure which was identified as being at risk and required mitigation.
The assets comprised of twin 700mm x 54M syphons with two manholes adjacent, on either side of a critical TFL embankment. Facilitating the inversion to the existing trapezoidal-shaped manhole (MH), we replaced it with a new structure comprising of a base slab and a 3-meter diameter MH ring. The construction of the new MH required careful consideration of hydraulic modelling to ensure uninterrupted flow of the TW sewer network. McAllister designed and built a bespoke flume which allowed the live sewer network to maintain continuous flow, between the two sides of the chamber, enabling the complete construction of the new MH.
Project Management
Our dedicated PM issued P6-CL32 programmes during monthly project meetings, the programme activity dates were approved by the client and integrated into the master programme. This ensured that all key milestones were completed prior to critical passing of the TBM.
The design and build programme consisted of two stages. Stage-1, planned for 8-months which encompassed surveys, MH-reports, cleaning, BIM-modelling and design, while Stage-2 included construction and lining lasted 4-months, continuous working was performed for each of the liner installations to minimise community impact.
As the cost target had been defined prior to construction, the commercial team prioritised diligent cost management in alignment with the intricacies of the project and its interactions with the client, supply chain and other stakeholders.
A collaborative approach was initiated from ECI stage to grasp the implications and complexities of the work. We instigated and managed regular meetings during the design, preconstruction, and construction phases, involving clients, asset owner, stakeholders, and construction team. The project benefited from this early engagement by considering mitigation for environmental impact, H&S hazards, CDM risk, buildability assessment.
Following the final design, a collaborative workshop was convened with all project stakeholders, wherein we delivered a presentation and secured the Letter-Of-No-Further-Comments from the asset owner to initiate the construction phase.
Throughout the project duration, the Quality Assurance team adhered to the Inspection Test Plan which was agreed pre-construction, post-construction. The handover pack was collated and issued to the client and asset owner to obtain the Final Certificate.
Community Impact & Customer Care
We created an Interference Register to assess the impact of our work and find ways to avoid or minimise disruption. As a result, we decided to use the CIPP Hot-cure method instead of traditional excavation. This approach reduces public interaction, minimises disruption to public transport, and leads to cost and schedule savings.
The Client had early engagement informing all locals and stakeholders of works scope, durations and potential impacts which created positive relationship with all near the worksite. They held regular public meetings and open workshops for all stakeholders and residents to attend, so they could raise any issues they had. Also, there were several allocated community liaison officers, who were the dedicated point of contact in addition to site specific visual aid to inform the community in case there were issues that needed to be raised. From our programme updates project timelines were regularly briefed and discussed with stakeholders, ensuring they understood how long the works had left.
Legislative Compliance
The design drawings comprehensively addressed all hazards and incorporated SHE information. This was elaborated upon and integration into the CDM Register, and subsequently transferred to the SSoW e.g. RAMS for submission to the client and asset owners for approval prior to issuing the work permit.
The primary Standards and Legislation are as follows:
• AM-DES-WWN-WWN44- SEC2 – Design Standard – Waste Network Gravity Sewers.
• AM-DES-WWN-WWN07 – Structural Sewer Rehabilitation, Sewage – Sewer Structures.
• H963-AA-NA-100-RP-C-1394 – TWUL Technical Note Contestable Works – Liner Design Guidance
• BS EN ISO 11296-4 – Plastics piping systems for renovation of underground non-pressure drainage and sewerage networks. Lining with cured-in-place pipes.
• GC/RT5122 – Application of the Construction (Design and Management) Regulations to Network Rail construction projects.
Sustainability
Throughout the delivery of this project, we have successfully implemented measures to significantly reduce our carbon emissions through four primary strategies. These include sourcing from local suppliers, minimising transportation emissions, utilising trenchless technology to diminish excavation requirements, and promoting electric vehicle adoption. We actively utilise sustainable materials from responsible sources to mitigate our environmental impact, showcasing our steadfast commitment to sustainability.
Carbon emissions:
• Direct emissions from our company-owned vehicles – 21.7-tCO2e
• Avoided emissions, reflecting the positive environmental impact by adding more electric vehicles into our fleet 0.20-tCO2e
The ensuing documents have been developed: an Environmental Management Plan crafted during the design stage, and an Environmental Reporting Pack prepared in the construction stage and subsequently presented to the client in the handover stage.
Innovation
Managing the varied complexity of the double-barrel twin-syphon asset during the design and build phase presented a significant challenge. The severity of the syphon bends limited the CIPP options, after careful optioneering it was decided that a hot-cure liner would be the most suitable solution with its flexibility to negotiate bends. This involved the installation of two 11.5mm thick RSM FERO FORCE liners, measuring 54m in length and 700mmØ. The Fero Force liner is designed for the application into pressure pipe systems, the structural analysis for the hydrostatic pressure at the base of the water column (15mtrs) necessitated the inversion of this type of liner, leading to the construction of a bespoke scaffold tower supported by a reinforced concrete foundation. The initial designs identified that to withstand a 15mtr hydrostatic pressure a standard felt, hot-cured liner would have been 35mm thick, this would have been problematic to negotiate the bends of the syphon and therefore deemed not suitable.
To ensure the robustness of the curing process, the new VERI-Cure system was introduced for the first time into curing a liner within a syphon of this type. The system utilises fibre optic control to monitor curing temperature in real time and generate a comprehensive curing report for quality assurance.
CLANCY GROUP / ONSITE FOR SCS JV
Thames Water Critical Asset Programme for HS2
Clancy was appointed by SCS (Skanska Costain Strabag joint venture) to develop a workable solution to their problem – the potential risk of damage to existing sewers due to ground movement from tunnelling operations. These trunk sewers, up to 1400mm in diameter are critical assets to Thames Water. Clancy considered a number of options including a pipe jacked solution adjacent to the existing sewer, however ultimately recommended the Cure In Pipe Process (CIPP) as it drove maximum efficiencies to the programme saving time, cost and reducing environmental impact.
We entered an Early Contractor Involvement (ECI) phase where we partnered with our key supply chain partner OnSite Central Ltd. Their industry leading knowledge was crucial for the successful delivery of the scheme. The importance of the work cannot be understated, as the Tunnel Boring Machines (TBM) were launched during the ECI stage meaning we had to design the liners, plan the works, and install the CIPP liners well in advance of the TBMs crossing the assets. The output from the design required the following:
ASSET / DIAMETER OF SEWER / LINER LENGTH / LINER THICKNESS
BRIDGEWATER ROAD 1200mm 110m 22.7mm
CARR ROAD 900mm / 1200mm 40m / 54m 10.1mm / 22.7mm
PARK ROYAL ROAD 1200mm 110m 20.9mm
GREAT CENTRAL AVE. 1400mm 162m 16.4mm
The original Clancy programme relied on concurrent working across the four assets allowing resource to flow from one site to another prioritising the assets based on the TBM programme.
We overcame significant workforce deployment challenges, sourced additional over pumping equipment and worked with our suppliers to ensure the availability of lining equipment to fit revised schedules of work.
It was immediately apparent that the biggest challenge to delivering the scheme was the substantial number of interfaces we would have to navigate. Rail, farmland, culverts, storage units, substations, public parks and even someone’s back garden had to be navigated.
The most notable example was a self-storage unit. We carefully dismantled a single storey block of their units to allow us access to the sewer underneath. Following completion of the project, we rebuilt the units using the old components and installed all brand-new roller shutters and fully re-laid the tarmac in their car park leaving the self-storage company significantly improved despite the disruption caused.
When opening the crown of the sewers, even with the substantial flows, there was often a foul smell. To combat this, we trialled a suppression system which neutralises the odour particles in the air and provides a sweet smell instead. This was of particular importance given the proximity of the excavations to the residential areas and public spaces.
The over pumping installation formed one of the major operations of the scheme. one main pump with three back up pumps with the capacity for 2000L/second flows. The 1000mm diameter pipe work was installed over farmland, through culverts, under rail, within trenches, over rivers and all manner of obstacles with one run totalling 1,200m in length.
Due to the depth of the sewers in some locations, we developed a series of bespoke steel frames with pulleys attached which were lowered down and weighed down with iron kentledge blocks. This allowed the winching cable to safely traverse down to sewer and provide adequate pulling force onto the liners. One shaft had to have a bespoke steel platform fabricated and installed to allow the tracked convey to work at the required proximity to the shaft. The site was so constrained, we brought the articulated lorry in for a trial run to confirm the working space and give the driver the confidence when delivering the liner itself.
Owing to the logistical constraints of the project, our designers Cowi UK Ltd pushed the design to the limits to reduce the thickness of the liner from 22.7mm to 16.4mm. This ultimately reduced weight of the heaviest liner to a total of 26,000kg which we believe to be one of the heaviest ever installed in the UK. Whilst this meant the liner would no longer be classed as a notifiable load giving us more flexibility in the delivery times, it was still too heavy for a conventional refrigerated container. OnSite manufactured and transported the liner from Germany and utilised independent refrigeration units within a conventional shipping container to maintain low temperatures during transport.
To install the liner with ease, OnSite deployed their bespoke, tracked conveyor rig which allowed the liners to be seamlessly pulled from the wagon, up and over the shaft edge and down into the sewer. This piece of equipment is essential for winching heavy liners without causing damage and mitigating the need for manual handling. The tracked nature of this rig is unique in the UK and provided us with the ability to move it into position on site where space was at a premium.
Some of the liners had to be installed in the middle of summer in excessive temperatures. OnSite made the decision to winch the liners, substantially reducing the risk of the liner curing in places and leading to quality issues.
Following the installation, all quality test results came back to specification with no issues to raise or rectify. The required strength results were achieved well in time for the TBMs to pass underneath the assets and no risk of standing them down.
Most importantly, the safety record on the project was exemplary. The were no major incidents, no RIDDORs and no Lost Time Incidents. The whole site team were briefed and adhered to our zero-tolerance safety culture ensuring nothing is more important than their personal safety. We employed very high standards of planning the delivery, working way over and above industry norms and ensured the operatives complied willingly. We had frequent health surveillance carried out at the various assets to ensure a healthy workforce.
The project also utilised a substantial amount of carbon reduction where possible. Solar generators being one of the best examples. A single generator saved 16,500L of diesel over a 7-month period reducing carbon emissions by 41,500kg. The use of HVO fuel came at a substantial financial cost to the project however the 115,000L of HVO proved valuable in reduced carbon emissions by an estimated 260,000kg.
MCALLISTER BROS LIMITED / THAMES WATER
Endwell Road, Sewer Crossing Rail
The Endwell Road UV Lining Project represents a comprehensive and meticulously planned initiative to upgrade 140mtrs x 600mmØ Thames Water sewer in Brockley, South East London. The critical sewer runs direct under and parallel between 4no railway lines on a busy commuter route into London.
The liner thickness of 18mm required longer curing protocols and as a result the installation had to be split into two (80mtrs + 60mtrs). Due to the rail possession incurring restricted working period both installs could not have been completed within the same line possession and therefore a second had to be planned. Through successful collaborative engagement, access was agreed with Network Rail, we were able to coordinate the project with other major works requiring lengthy weekend possession allowing the works to be planned. A complex two phased flow management setup was installed to manage up to 220ltrs per second with a primary capable of 120ltr p/sec and a back up to start if flows increased to cope with the additional 100ltrs p/sec. The over-pumping restricted local access to certain streets and properties, our customer teams ensured that all customers were aware of the impact of our works and what alternative parking / access arrangements had been arranged.
Due to limitations associated with the working window the project was delivered in phases:
Phase 1 – Surveying (defining scope) optioneering and design
Phase 2 – 80mtrs UV Liner install
Phase 3 – 60mtrs UV Liner install
The project had been in the planning and development for two years. The prolonged lead in was result of project coordination with stakeholders and access constraints. During the planning stages, McAllister had been liaising with local authorities and TFL, in order obtain the streetworks permits.
The access point for installation plant was over 2.2 miles from the installation location and additional specialist Road Rail Vehicles (RRV) was arranged with a rail contractor to ensure that the liner could
be safely transported to site, and compliant lifting apparatus was available to facilitate the lift of the liner to the access manhole trackside. The project management team, employed a structured approach to ensure the project’s success. The detailed Work Package Plan (WPP) encapsulated a robust framework for task execution, risk management, and resource allocation. Specific roles were assigned to ensure accountability and effective communication among stakeholders, including Network Rail and Thames Water representatives.
The project’s timeline was carefully crafted to minimise disruption to the community, with strategic planning around 2 x 52-hour possession windows to complete the liner installation. Traffic management measures, site inductions, and a rigorous change management protocol were established to maintain safety and efficiency throughout the project
Community Impact & Customer Care
The Endwell Road project had a significant positive impact on the local community by improving the sewer infrastructure, thereby reducing the risk of sewer failures and associated health hazards. Community care was prioritised through transparent communication and proactive stakeholder communications. Traffic management strategies were implemented by McAllister, in order to minimise inconvenience to residents and commuters.
Notice boards and bulletins were displayed prominently to keep the community informed about the project’s progress and any potential disruptions. The project team also ensured pedestrian access around the worksite was well-managed, with clear signage and safety measures in place.
The team demonstrated exceptional customer care by proactively engaging with local authorities and residents to address concerns and provide updates. This open line of communication helped build trust and ensured the community was well-informed and supportive of the project.
Legislative Compliance
Compliance with legislative requirements was a cornerstone of the Endwell Road project. The WPP outlines adherence to health, safety, and environmental regulations, emphasising the principal contractor’s accountability for meeting statutory requirements.
Key compliance measures included:
• Site-specific risk assessments and method statements to identify and mitigate hazards.
• Carefully choosing railway critical staff (i.e COSS, hand-back engineers)
• Confined space entry procedures, including gas testing and permit arrangements.
• Regular toolbox talks and safety briefings to ensure all operatives were aware of safety protocols and emergency procedures.
• Coordination with local authorities to secure necessary highway permits and authorisations, ensuring all traffic management setups adhered to Chapter 8 regulations.
• AM-DES-WWN-WWN44- SEC2 – Design Standard – Waste Network Gravity Sewers.
• AM-DES-WWN-WWN07 – Structural Sewer Rehabilitation, Sewage – Sewer Structures.
• H963-AA-NA-100-RP-C-1394 – TWUL Technical Note Contestable Works – Liner Design Guidance
• BS EN ISO 11296-4 – Plastics piping systems for renovation of underground non-pressure drainage and sewerage networks. Lining with cured-in-place pipes.
• GC/RT5122 – Application of the Construction (Design and Management) Regulations to Network Rail construction projects
These steps ensured the project met all legal requirements, safeguarding the well-being of both workers and the public.
Sustainability
Sustainability was integral to the project’s planning and execution. The UV lining technique itself is a sustainable solution, providing a long-lasting, durable sewer lining that minimises the need for future maintenance and associated disruptions, and also there are no negative impacts on the rail infrastructure.
Environmental management arrangements included:
• Noise control measures to minimise disruption to the community and wildlife.
• Air quality monitoring to ensure emissions from construction activities remained within acceptable limits.
• Strategies for handling and disposing of waste materials responsibly, including protocols for dealing with potential contamination and spillage.
• Over-pumping, designed to include mitigation for storm conditions.
The project team also incorporated measures to reduce manual handling risks and improve ergonomic safety, contributing to overall project sustainability by promoting worker health and safety.
Innovation
Innovation was a key driver of the Endwell Road project’s success. The use of UV curing technology for sewer lining represents a cutting-edge approach in infrastructure maintenance.
The selection of the lining material was carefully chosen, based on the complexity of the existing asset. The Alphaliner has high strength characteristics, even in lower thickness, which allowed this liner to be installed around the bend.
This method offers several advantages, including faster installation times, reduced environmental impact, and improved durability compared to traditional methods.
The project also leveraged advanced CCTV technology for pre- and post-installation surveys, ensuring precise assessments of the sewer condition and the effectiveness of the UV liner. This technological integration allowed for accurate planning and execution, reducing the risk of unforeseen issues and enhancing project efficiency.