Network Rail Design Services Framework

• Site inspections, ground investigations and surveys of existing railway and highway structures;
• Assessment of existing structural assets and including detailed knowledge of historical structure types and materials such as masonry, iron and early steel structures;
• Remedial design of repairs and structural strengthening;
• Design of new structures including bridges, retaining walls, culverts, tunnels, and ancillary structures;
• Safety critical documents and approvals;
• Liaison for third party approvals i.e. heritage or environmental;
• Detailed knowledge of Network Rail codes, requirements and their approvals process
• Specialist surveys including environmental reports and intrusive investigations;
• Principal Designer Role through design and construction;
• Forensic GAP analysis of proposed Crossrail Station Design Submission.
• Asset Protection Project Engineer Secondments reviewing third Party submissions on HS2.
• Production of standardised design manual for UK Masterseries OLE support structures.

• Honeywicke Retaining Wall

Robert Bird Group undertook the structural survey of a failing retaining wall at the foot of a steep embankment directly adjacent to main railway lines in Bristol. Following the survey we were able to develop a hybrid strengthen and repair design proposal including sprayed concrete and rock anchors to secure the existing retaining wall. The design had the benefit of minimal ground-works and construction time when compared to a traditional retaining wall replacement and it is expected that it will be built in standard engineering hours with minimal disruption to the operational railway.

• Bishopsteignton Culvert

Bishopsteignton is an under-track culvert providing tidal drainage on the high risk coastal west coast main line. Previous condition assessments of the culvert had shown that the structure was in a state of disrepair and Robert Bird Group (RBG) were contracted to provide an off-line pipe jacked replacement. Due to the tidal location of the structure it was expected that a cofferdam would be required for construction. Upon review of the site geology, RBG concluded that coffer-damming would be extremely difficult and expensive to achieve. RBG proposed an alternative design solution that would encompass reuse of the existing culvert, significantly improving the sustainability and cost of the scheme for the Client. RBG then lead third party approvals for environmental and drainage consents.

• Downside Rail

A section of retaining wall supporting the West Coast Main line had undergone progressive failure and Robert Bird Group were contracted to design repairs. During options analysis stage it became clear that the wall was continuing to fail and to protect against complete collapse Robert Bird Group devised a temporary propping scheme to ensure the main line was able to remain open. The subsequent permanent repair included replacement of the failing sections of wall with a modular ‘backwards’ cantilevered reinforced concrete wall. Construction sequencing and methodology were carefully considered in the design to allow construction of the wall with no disruption to the operational railway with only minimal monitoring.

• Rainbow Hill Tunnel

Rainbow Hill Tunnel is a 180m brick lined tunnel that required repair. During the project Robert Bird Group were able to resolve a persistent issue facing tunnel repair projects, where design drawings are difficult to utilise on-site with defect locations scaled inappropriately or difficult to locate. Robert Bird Group proposed utilising an innovative point cloud with 360 HDR photography survey to reproduce a detailed model of the entire tunnel and elevations. This had the dual benefit of significantly reducing survey time and provided a resource for design. The tunnel model was ‘unwrapped’ for the Contract drawings and the digital model was provided to Network Rail and their Contractor for construction.

• Windsor Viaduct

The structure is a 24-span arch masonry structure carrying a single bi-directional non-electrified line. The structure has a low overall BCMI score with several defects associated with open joints, displaced brickwork, spalling and extensive drummy areas. The project team chose to utilise a UAV drone with mounted camera to capture track positions and levels, significantly reducing trackside survey requirements and improving on-site health and safety. Project innovations included utilising RING masonry arch analysis software to determine if the viaduct could remain open to railway traffic during refurbishment, providing a significant cost saving to Network Rail at construction stage.

• Durley Somerdale Masonary Arch Underbridges

As Network Rail strive towards net zero carbon emissions, Robert Bird Group were able to utilise advanced structural analysis methodologies to provide significant sustainability gains on this repair and strengthening project for a grade II listed station footbridge.

Previous project experience of historical metallic footbridges has shown that they are often ‘over-strengthened’ when traditional analysis is employed, resulting in significant additional embodied carbon from the additional steelwork required. Robert Bird Group produced a full 3D Finite Element Model to undertake non-linear assessment methodologies which enabled proof that the load carrying capacity of the footbridge was higher than previously thought, allowing for a more efficient targeted and sustainable repair design.

• Stroud Footbridge

Durley Somerdale is a Grade II listed masonry arch underbridge designed by I.K. Brunel. Robert Bird Group undertook the design for repair of the historically significant bridge, including preparation of liaison approvals documentation for listed buildings consent.