The M25 road network, originally constructed in the 1970s, has traditionally relied on solutions like steel plate reinforcement to stabilise its structures. However, during the planning phase for strengthening works on the east bridge at the Swanley Interchange, the collaborative team—Octavius, Connect Plus, Connect Plus Services, and Atkins—identified that this approach wouldn’t provide a long-term solution due to the extent of the road’s deterioration. The collaborative team devised a bespoke innovative engineering solution, the installation of carbon-fibre-reinforced polymer (CFRP) rods . The rods are lighter weight, less likely to crack and able to better withstand the harsh environmental conditions and heavy forces in comparison to traditional steel plates. CFRP rods also remain resistant to corrosion, ensuring that any structural components made of carbon fibre will maintain their operational integrity over a longer time.
The Octavius team successfully completed renewal works on the east and west bridge, in total installing 364 CFRP rods. The installation of carbon-fibre rods on the Swanley Interchange was a first for both the M25 and the UK. This project sets a new standard, paving the way for further adoption of CFRP rods across the M25 network.
A sustainable solution
The use of CFRP rods significantly reduces CO₂ emissions. By replacing traditional materials, we saved over 8,100 tonnes of CO₂ throughout the project, contributing to a lower carbon footprint.
Time saving
After removing the original surfacing, waterproofing, and grout layers, grooves were cut into the existing deck slabs to accommodate the installation of the rods. To help save time and ensure the work was completed to programme the team developed a bespoke bracket to enable saw-cutting 12-meter tracks.
This innovative bracket features a retractable extended arm, allowing multiple grooves to be cut in one anchoring setup. This streamlined process eliminates the need to reposition the bracket after each groove, resulting in a timesaving of approximately four hours per shift leading to an overall 10% programme reduction.
The project was recognised at the 2024 Highways Awards, where Octavius and its partners received a Highly Commended award in the Innovation category, celebrating their ground-breaking work and contribution to infrastructure resilience.
