Sarens successfully executed the final lift for the Thames Tideway Tunnel, London’s ambitious “super sewer” project. This massive engineering effort aims to divert millions of tonnes of storm sewage from the River Thames each year. Set to be fully operational in 2025, the 25-kilometre tunnel will significantly reduce the overflow of sewage into the river, protecting both the environment and public health.
Sarens was brought in by CVBJV, a joint venture between Costain, Vinci Construction Grands Projets, and Bachy Soletanche, to handle the installation of the substantial circular shaft cover at the Abbey Mills Pumping Station in Stratford. This cover, a 1,200-tonne precast concrete slab, was specifically designed to seal the top of the tunnel shaft. However, given the enormity of the lift, it required a series of custom-built solutions from Sarens, including a specialized gantry system and an array of heavy-lifting equipment.
For this complex task, Sarens deployed a combination of specialized equipment, including Kamag self-propelled modular transporters (SPMTs), modular beams, HSL6500 strand jacks, and the CC 2800-1 crawler crane, along with bracing systems. The preparation and planning spanned from February to April 2024, with Sarens meticulously coordinating every aspect of the lift. Limited on-site space presented a significant challenge, particularly for assembling the gantry system, while also managing the logistics of transporting approximately 50 truckloads of equipment from Belgium and Southampton.
Sarens took considerable measures to manage these constraints, including careful consideration of each component’s weight and its potential impact on underground services. It took nearly two months to set up all the equipment, a process made more difficult by the confined space. The CC 2800-1 crawler crane was crucial in building the gantry, while eight precise lifting points were established to control the load’s movement with exacting accuracy.
The lifting itself was an impressive feat, requiring five hours of intense coordination. Eight 650-tonne strand jacks were employed to raise the shaft, and the structure was then transported on 64 axle lines of SPMT. The operation demanded the full expertise of a 12-member team, who were tasked with managing each step of the process, from planning to the final lift.
Sarens’ successful completion of this lift marks a critical milestone for the Thames Tideway Tunnel project, bringing London closer to a cleaner, safer future for its iconic river.
