Balfour Beatty VINCI SYSTRA’s construction of HS2’s new super-hub station in west London, Old Oak Common, has moved into a new phase as workers on the project completed the excavation of the huge underground box structure where high speed trains will stop. The excavation has taken three years, after permanent construction to form the walls of the box began in June 2021. The vast underground box has a 1.12 mile fibre-reinforced concrete diaphragm wall around it, and 1.3million tonnes of London Clay has been removed from inside – enough to fill over 300 Olympic sized swimming pools. Balfour Beatty VINCI SYSTRA joint venture (BBVS JV), working with their specialist structures contractor Expanded, completed the excavation with apprentice Miguel Jardim removing the last of the London clay from the box. In a further breakthrough, more than 1,500 apprentices have now started work on HS2 – putting the project firmly on track to meet its target to generate 2,000 apprenticeships. Miguel, 19, a civil engineering apprentice from Surrey Quays, south east London, joined in the landmark excavation at Old Oak Common as the 1,500th apprentice to start a role helping to build HS2. Miguel said: “It is quite an honour to be part of celebrating such a massive excavation milestone – the opportunity came along very unexpectedly! “The best thing about my job here at Old Oak Common is all the experience I’m gaining from going out onsite daily, seeing progress coming along. I would 100% encourage others to start working on HS2, as it’s a massive project where you get to work with lots of people with similar goals. There is also a great network of people that you can learn from and connect with.” Steve O’Sullivan, Project Director, Balfour Beatty VINCI SYTRA joint venture, said: “This achievement is a testament to the dedication and hard work of our team, and in particular the valuable contributions of our apprentices like Miguel. “The progress here at Old Oak Common moves us one step closer to completing this key transport hub, which will enhance connectivity and drive regeneration in the area. We are excited to move forward to the next phase of construction and continue delivering this transformative project.” The excavation was completed section by section within the box starting from the west and the east of the structure and meeting in the middle. The box is 20m in depth and a reinforced concrete base slab up to 2m in depth is being poured throughout. 32,000 tonnes of steel rebar, assembled by hand on site, has been used in the box alongside 160 reinforced concrete columns which have been installed inside the outer wall to help support the structure. All steel used was 100% responsibly sourced and most of the concrete used is produced by the London Concrete batching plant on site, which reuses rainwater in its mixes. Now the box has been full excavated, the team will be working to pour the final sections of base slab to fully complete the box. Six 450m platforms will be constructed in the underground box for HS2 services. Above ground, eight further platforms are being built, and will be served by the Elizabeth Line, Great Western Mainline services and the Heathrow Express. Old Oak Common station will become one of the country’s most vital transport hubs which will be directly connected on the UK’s railway network to more than 170 destinations. Sam Clark, Head of Delivery for HS2 Ltd, said: “The tremendous progress made by our construction team to complete the excavation of the box is an exciting milestone for the project as it signals the next phase of construction where high speed platforms will be built, as well as the station building itself.   “HS2’s Old Oak Common station will be transformational for local and regional connectivity and attract huge investment, development and regeneration to the surrounding area.” The huge amount of London Clay removed in the excavation has been taken away from site by conveyor, reducing lorry movements on local roads. The conveyor, run by the Subcontractor Fairport, took the spoil to the nearby London Logistics Hub, managed by Skanska Costain STRABAG (SCS JV), from where it has been transported by rail to beneficial reuse sites in Kent, Warwickshire and Cambridgeshire. Coinciding with the excavation of the box, HS2 has decommissioned the Old Oak Common station conveyor which has removed over 75,000 lorries from the road since it’s operation in November 2022. Further spurs of the conveyor being used for HS2’s tunnelling operation in the area remain in use. HS2 has also been working with local artists on projects to reuse the London Clay. Absolute Beginners is an arts project led artist Tom James, where local young people are learning to use the clay to make objects. The group began using the clay to make a simple plate, learning how to process, manipulate and fire the clay. The group are now making a dinner service of 100 plates and 100 bowls from some of the excavated materials.   The east end of the underground box has been handed over to HS2’s London Tunnels contractor, SCS JV, who are preparing to construct HS2’s running tunnel to Euston. Two giant tunnel boring machines will be lowered into the underground box later this year, before the station team commencing building the roof structure of the super-hub station. Timings and funding for the construction of the Euston Tunnel are being confirmed with government. When HS2 opens, Old Oak Common will be the temporary terminus in the capital. Plans to transform the wider area around the station, a former railway and industrial site, are being led by the Old Oak and Park Royal Development Corporation (OPDC). Plans are in place to deliver 25,000 new homes and 56,000 new jobs in the area surrounding the station, transforming London’s biggest brownfield site into a thriving community for businesses and residents alike Building, Design & Construction Magazine | The Choice of Industry Professionals

The main contractor, Balfour Beatty, approached Aquaspira with a request to provide a proposal for an efficient, low carbon solution for a Network Rail culvert alongside a rail embankment at Hook in Hampshire. Sub-contractor DDL installed a dam at each end of the fast-flowing river below the rail line at Hook in Hampshire. This created a 40-metre-long channel to facilitate the delivery of a new 26-metre buried culvert. Needing to overcome the challenge of an incredibly confined space, two lines of Aquaspira 1,650mm composite steel reinforced (CSR) pipe was laid once the water had been pumped out and a metre of silt removed from the riverbed. These were finished with a new 4.8 metre, 350m-wide headwall. The pipes were then backfilled and built up to existing ground line and an access road was installed to provide Network Rail plant access to the above railway line. With Aquaspira CSR pipe, the embodied factory gate and transport carbon was reduced by 48% (12.4T CO₂e¹) when compared to a traditional rigid pipe solution. The lightweight pipes also increased site safety and reduced site installation time. The steel reinforced pipes were designed to withstand the weight of trains, so Aquaspira is delighted to have been selected to deliver the ideal solution for this challenging job. Gareth Green, Aquaspira’s project manager, explained: “The existing open culvert was relatively narrow, so maximising the capacity of the new piped culvert within the available width was crucial. “Aquaspira CSR pipes were specified as, with their 43mm thick wall, the pipe’s footprint width was less than 3.8m and, as each pipe weighs less than 250 kgs, they could be handled and installed with small site machines. This, coupled with the push-fit joints and integral seals enabled quick and simple joining of them within a limited working space, dramatically shortening the programme time.” Josh Moore, DDLWorks Manager, added: “The Aquaspira service and product was excellent. The 1650mm OD pipes were the largest I have installed, and it was made so simple through their design and self-explanatory installation guide provided, along with assistance via phone call at any moment required. I would 100 per cent recommend you to any client or customer and look forward to working alongside again in the future.” Building, Design & Construction Magazine | The Choice of Industry Professionals

Leading civil engineering and building contractor Farrans Construction has completed an innovative tunnelling operation on Northumbrian Water’s Project Pipeline: County Durham and Tees Valley as a specialist tunnel boring machine has completed an underground crossing of the River Tees. The 220m tunnel is part of Phase 1 of a new £155m water pipeline to be constructed while protecting the watercourse and the wildlife that relies upon it. Northumbrian Water’s Project Pipeline: County Durham and Tees Valley will see the construction of around 57km of new pipes connecting Lartington Water Treatment Works with around 200,000 customers across the south of the North East. The specialist tunnel boring machine arrived on site in April to begin its journey between two specially constructed shafts. This operation has created a pathway beneath the river, through which the new pipes will be installed. Phase 1 of the project will connect Lartington, in Upper Teesdale, with Whorley Hill and Shildon, County Durham, and will be followed by a second phase extending the pipeline from Whorley Hill to Long Newton, connecting to the existing network that serves large parts of Teesside. In recent months, work has been carried out by main contractors Farrans and subcontractors Joseph Gallagher, to create the two shafts, one on either side of the river. The western shaft is 8.0 metres in diameter and 32 metres deep, while the eastern shaft is 7.5 metres in diameter and 46 metres deep, the difference being due to the rising topography on the east bank. Dave Mellor, Contracts Director for Farrans, said: “This highly technical and challenging operation has been a best-practice example of innovative civil engineering and we are delighted to have completed it successfully and on schedule. I would like to thank our team, our specialist contractors Joseph Gallagher and our client for collaboratively achieving this important milestone in a project which will secure the water supply to this region for years to come. The moment of break through into the west shaft was a cause for celebration on site following weeks of slow, incremental progress to create the tunnel.” James Dawes, Northumbrian Water’s Project Manager said: “This project has been years in the planning, and ensuring that key strategic crossings, such as the River Tees, are done in the best way possible for the local environment and communities, has been vital. “While it would have been possible to cross the Tees using a pipe-bridge, we had to consider such factors as how this would impact the stunning Teesdale landscape that will be here long after our team have completed the project and moved on. “The use of no dig techniques, tunnelling or directional drilling, is becoming increasingly common in our projects, to reduce the impact on our region’s road and rail networks by reducing the need to dig long trenches. However, this is the first time we have employed it to cross a large river and the teams at Farrans and Joseph Gallagher Limited have done a great job to make this possible. Project Pipeline: County Durham and Tees Valley is a huge investment in the resilience and quality of water supplies to around 200,000 customers, and there is a lot of work to be done, but this is an exciting and important milestone as we progress this strategically important project towards completion.” Building, Design & Construction Magazine | The Choice of Industry Professionals