LOCATION:
The Castle Inn Bridge in Treforest, a Grade II Listed three-span masonry arch bridge, served as a vital pedestrian link between Cardiff Road (A4054) and River Street (B4595), near the University of South Wales and Treforest railway station. Due to its age and structural limitations, the bridge was closed to vehicular traffic and only accessible to pedestrians. The area is also prone to flooding, worsened by the bridge’s piers obstructing the River Taff’s flow.
The project involved the complete replacement of the existing bridge with a new single-span steel truss bridge, designed to Active Travel standards for pedestrian and cyclist use. Key activities included:
- Road closures and traffic/pedestrian management
- Temporary service diversions, including BT catenary wire support
- Coordination with third-party contractors for sewer over-pumping
- Demolition of the existing masonry bridge
- Construction of reinforced concrete plinths and scour protection
- Building new abutments, wing walls, and a west approach ramp
- Assembly and installation of the new bridge superstructure
- Remedial works to the south-east training wall
Challenges
- Flood risk: The existing bridge piers contributed to river flow obstruction and flooding.
- Heritage constraints: As a Grade II Listed structure, the bridge required sensitive handling and heritage-conscious design.
- Service diversions: Managing live utilities, including BT and DCWW infrastructure, required careful planning and coordination.
- Access and safety: Ensuring safe pedestrian and traffic flow during construction in a busy urban area.
Solution
A single-span steel truss bridge was selected to eliminate in-river piers, improving hydraulic performance and reducing flood risk. The design incorporated heritage elements to respect the historical significance of the original structure. Temporary works, including crash decks and service supports, were implemented to ensure safe demolition and construction. Close collaboration with utility providers and third-party contractors ensured minimal disruption and efficient execution.
Outcome
The new Castle Inn Bridge now provides a safe, accessible, and flood-resilient crossing for pedestrians and cyclists.
It enhances connectivity for local residents and university students while preserving the historical character of the site. The project successfully mitigated long-standing flooding issues and delivered a modern infrastructure solution aligned with Active Travel goals.
