Port of Tilbury Grain Storage Silo

Key challenges included the live port environment, coordinating structure interfaces and managing the complex utilities and M&E installation. Close coordination and daily engagement with the client’s operational teams ensured maximum safety and minimal stakeholder disruption.

The Port of Tilbury is a large industrial hub with constant vehicle, rail and crane activity. The Silo 4 site, located within an operational grain terminal and adjacent to the Thames River wall, posed additional challenges. Although the original structure had been demolished earlier, works included dismantling sections of the steel frame connected to the adjoining Centre House and its complex 1960s conveyor systems. To ease the site’s constraints, an offsite laydown and storage area was used. Weekly coordination meetings, led by the Port Operations Team, brought together all stakeholders - architect, structural engineer, DSEAR consultant and M&E specialist - to ensure safe, efficient logistics.

We used our design management and operational knowledge of complex M&E works on similar projects to manage the M&E subcontractor, TH White, who delivered a fully integrated mechanical and electrical solution that met stringent ATEX compliance and operational safety standards. The scope of works included the design and installation of high-capacity chain conveyors, an aspiration system to manage dust and displaced air, and a new suite of motor control centres (MCCs) housed in a purposebuilt switch room, complete with a dedicated transformer. Future-proofed cable containment was implemented, and all necessary cabling was installed for plant equipment, lighting, and monitoring systems. This included the integration of radar-based level monitoring and temperature sensors to support safe and efficient grain storage operations.

Coordination was carried out with software engineers to ensure seamless integration of the new systems with the existing grain terminal controls, particularly in interfacing with Silo 3. The team’s involvement extended through to commissioning, providing support for software route testing, machinery dry runs, phased silo filling, and final performance validation.

Utility works included the design and build of new potable and rising main feeds, including pumps and break tanks to accommodate foul discharge from high to ground level. Our value engineered solution minimised disruption by introducing a new rising main pipe through the existing 2m deep tunnel and resolving poor potable water pressure by boosting water to a higher level to feed existing infrastructure.

Construction faced the challenging Thames alluvial geology. To address this, our piling subcontractor Keller Geotechnique installed 409 fully cased, bored concrete piles down to the chalk and gravel layer 28m below. Instead of conventional pile caps, we designed 72 ‘elephant foot’ columns, each supported by multiple new and existing piles. These columns have a 4.4 x 2.0m base tapering to 2.1 x 0.92m and rise 4.5m to form an undercroft. At this level, a 750mm heavily reinforced concrete bin slab was cast before transitioning to slipform construction.

The slipform provider used a modified version of their proven two-level slipform rig, offering safe access, partial weather protection, and the ability to carry out distinct but closely spaced operations for long periods of time. The entire frame was supported and raised using hydraulic jacks spaced at 2m intervals on vertical rods cast into the core walls, with lasers ensuring accurate vertical alignment. High-tensile steel reinforcement cages (25–30mm diameter) were assembled in situ, with box-outs installed at upper levels. Concrete was placed via two gantry-mounted booms and compacted using vibrating pokers, while finishing work was performed at the lower level as the concrete emerged from the 2.5m-tall shutter. A total of ten C32/40 and C40/50 concrete mixes were trialled in advance to suit varying slipform speeds and conditions, with admixtures adjusted accordingly. A ridge feature was also formed along the centre line to support precast roof planks.

Continuous quality control monitored concrete temperature and strength, with cube tests performed on every delivery. To ensure grain safety, the design avoided dust-trapping ledges, and reinforcement density was maintained uniformly over the entire 37m height of the 300mm-thick structure to ensure it could withstand an explosion. Perfect alignment of the new conveyors with the reconfigured steel frame and existing mechanical systems was achieved through cloud-point laser scanning.

As part of the project works, we installed two key elements of precast concrete. The first comprised precast concrete hoppers at the base of each of the 30 silo bins. These hopper units were designed and manufactured in the port area, where we established a dedicated manufacturing yard in close proximity to the project site. Each hopper unit consisted of four primary base units, cast with lifting eyes to facilitate safe and efficient installation.

In addition to the precast hoppers, we installed precast roof planks on top of the silo bins. These were procured through our supply chain and installed by our lifting team in accordance with the construction programme.