Project overview
School Hill Overbridge is a two-span green bridge being delivered over the HS2 main line and the relocated MCJ3 line. The structure will carry a single carriageway while also providing a dedicated wildlife corridor, combining major civil engineering with long-term ecological connectivity.
Key info
- Two-span green overbridge
- Dedicated wildlife corridor
- 52m span and 40m width
- 6000m³ of concrete & 1000T of reinforcement
- Prestressed concrete beam deck
The bridge spans 52m and is 40m wide, with a prestressed concrete beam deck supported by reinforced concrete abutments and foundations. The works require approximately 6,000m³ of concrete and 1,000 tonnes of reinforcement.
Delivery
Substructure works
The reinforced concrete package includes the bridge foundations, pile caps and abutments supporting the new deck structure.
Piling was completed in summer 2024, followed by the pile caps in October. This established the main substructure and enabled construction of the abutments and preparation for the deck installation.
Deck construction
The bridge deck is formed using prestressed concrete beams, which will create the two-span structure over the railway alignment.
Beam installation is scheduled for May and June, with the full formwork, reinforcement and concrete package expected to be completed by late 2025.
Environmental integration
The overbridge has been designed to serve both transport and ecological functions.
Alongside the single carriageway, the structure includes a dedicated green corridor to support the safe movement of wildlife across the HS2 and MCJ3 rail lines. This approach integrates habitat connectivity directly into the bridge design rather than treating it as a separate feature.
Technical delivery
At 52m long and 40m wide, the structure requires significant volumes of reinforced concrete and careful coordination between piling, substructure, beam installation and deck works.
The bridge package includes:
- Reinforced concrete foundations
- Pile caps
- Reinforced abutments
- Prestressed concrete beams
- Deck and associated concrete works
- Integrated wildlife corridor
Programme
The works are being delivered through a phased sequence:
- Piling completed in summer 2024
- Pile caps completed in October 2024
- Beam installation planned for May/June
- Full FRC completion targeted for late 2025
This sequencing allows the main reinforced concrete works to progress alongside the wider HS2 programme.
Conclusion and summary
School Hill Overbridge demonstrates how major infrastructure can be designed to support both transport requirements and the surrounding environment.
The project combines large-scale reinforced concrete construction, prestressed beam installation and ecological design within one 52m by 40m structure. Once complete, it will provide a new carriageway crossing while maintaining safe passage for local wildlife.
