The UK’s heaviest single-span bridge was recently moved into place by Osprey at Gipsy Patch Lane in Bristol, Helen Batt explains how

Efficient road and rail networks are crucial for the economy. For many rail projects, the biggest challenge is time. Respecting
multiple stakeholder schedules, mitigating disruption. Osprey Group provided a suite of special logistics to help minimise the disruption and replace the existing brick structure at Gipsy Patch Lane in Bristol with a single-span concrete bridge. In all, the project took eight months from start to finish. But the transportation and installation of the single portal structure – weighing over 5,200 tonnes – took place over just one weekend. This project is a landmark in rail installation, as it marks the site-to-site transportation and installation of the UK’s single heaviest rail structure.

 

Challenge – super-structure size

The challenge was one of size and space: Network Rail needed to put in a new railway bridge at Gipsy Patch Lane on behalf of
South Gloucestershire Council. The Gipsy Patch Lane bridge is one of several in this programme of work for Network Rail, but it is the largest and the heaviest. As a single-span superstructure (part of the £57 million investment into Cribbs Patchway MetroBus Extension scheme), the new bridge would reduce congestion in the area and improve journey times for all road users with a new public transport system and an alternative to travelling by car – but the span’s weight and construction
made this a challenging ask. The timetables involved were dictated by a need to minimise disruption, and the pandemic became a factor in increasing that pressure involved were dictated by a need to minimise disruption, and the pandemic became a factor in increasing that pressure.

Solution – Osprey’s specialist logistics and installation

Osprey Group was asked to deliver a full suite of specialist logistics by Alun Griffiths (Contractors) Ltd, the prime contractor to Network Rail. The project began with the removal of overhead railway line equipment, and the dismantling and removal of existing railway track and ballast. The existing bridge was demolished and removed, and over 30,000 tonnes of earth needed to be excavated.

Osprey’s previous experience of transporting and installing giant assets – everything from the same kind of railway engines that use the Bristol line, to renewable wind farm turbines or nuclear power plant components – meant they approached the challenge with a multidisciplined team that work with innovation in mind. On this project, this included fitting all cabling and electrics to the deck of the super-structure while it was at ground level, in the storage compound.

Osprey’s Project Manager, Mitchell Smith said: ‘Our approach to installing fixtures at ground-level has set the standard for this
kind of project now. We reduce the risk of working at height instantly, and that fixtures’ installation can happen in parallel – there’s no need to factor that additional time in to the project plan now.

The project did face challenges, but we quickly found ways to adapt and, in fact, improve our health and safety approaches – making it possible to work collaboratively with our suppliers and move the single-span superstructure into place in the shortest amount of time possible.’ Osprey keeps a large inventory of heavylift equipment and transportation on call night and day, drawing on its own specialist logistics’ stock to plan and execute end-to-end logistics.

The single-span was moved on a 144-axle self-propelled modular transport (SPMT) unit with 576 individual wheels – the SPMTs lifted, manoeuvred and lowered the entire portal into position. Osprey also used an innovative arrangement of hydraulic jacks and longitudinal beams, this pre-stressed bracing effectively ‘held the walls apart’ to maintain its form during the move, ensuring installation of the portal in the designed foundations. Assets of this strength do have flexibility built into them for their long term structural purpose, a factor that must be incorporated in what, in the life of the structure, is a very short transport and installation phase. In all, the portal structure and installation equipment weighed 5,200 tonnes, over half the weight of the Eiffel Tower.

Results – working collaboratively delivers innovation

This way of working significantly reduced the amount of time that Osprey’s ground team needed to be on site, which was
an instant benefit to project planning. However, it is also delivered a benefit to the local community – it means their lives were
disrupted far less. The new bridge will bring communities together, reduce commuter times, and provide a boost to the business environment that helps the local economy. Mitchell said: ‘The Gipsy Patch Lane bridge will reduce commuter times for several major employers. We were proud to play our part in preparing for the future, helping our local Bristol community to re-establish even better connections with an improved transport network. What’s more, many of our team live in the local area, so it was rewarding to work on something that will have such a long-term impact – this new bridge should be here for at least the next 125 years.’