Bristol Airport: Post-Tensioning & Precast Excellence

The new £60 million multi-storey car park and transport hub at Bristol Airport is more than just a parking facility — it is a testament to modern engineering, collaboration, and sustainability. Designed to support the airport’s expansion to 15 million passengers by 2036, this project delivers 3,000 new car parking spaces and an integrated transport exchange directly linked to the terminal via a new bridge.

This project exemplifies what’s possible when industry leaders work together. The collaboration between Interspan (post-tensioning design & build), Kerkstoel (precast concrete), Statom (RC frame contractor), and Farrans (main contractor) set a new benchmark for delivery.

Originally planned as a 35-week programme, the structure was delivered three months early, ensuring readiness for the busy 2025 summer season.

Innovative Design for Sustainability and Efficiency

From the outset, Interspan offered a post-tensioned (PT) floor slab solution as part of a competitive framework. When compared to a conventional reinforced concrete (RC) scheme, this approach achieved:

• 2,400 tCO₂e saved — a significant reduction in embodied carbon.
• Improved material efficiency and reduced waste.
• Faster programme delivery and high-quality finishes.

By integrating Kerkstoel’s precast biscuit slabs, the hybrid design overcame live load requirements for EV-ready car parks and allowed the structure to be completed three months ahead of schedule.

Advanced digital coordination aligned design, prefabrication, and site installation, ensuring precise placement of rebar cages, PT ducts, and services.

• Other sustainability and efficiency benefits included:
• Reduced on-site labour, waste, and rework.
• Lower concrete and rebar volumes thanks to PT design.
• Enhanced overall project sustainability.

High-Quality, Exposed Concrete Finish

With the concrete structure remaining exposed throughout its life, finish quality was crucial.

• Precast biscuit slabs from Kerkstoel ensured consistent, crack-free finishes thanks to factory-controlled conditions.
• Post-tensioning provided superior crack control, enhancing durability and appearance.
• Close coordination between Interspan, Statom, and Kerkstoel enabled fast, safe, and clean on-site installation.

Repeatable and Scalable Solutions

The combination of precast biscuit slabs with in-situ PT beams and slabs offers a highly repeatable and scalable model for:

• Multi-storey car parks
• Large-span offices and public buildings
• Multi-storey data centres

In-house Design Excellence

Interspan’s in-house engineering team leveraged advanced tools like RAM Concept and RAPT to deliver optimised slab designs and detailed construction solutions. This tight integration of design and delivery played a key role in achieving early completion and high-quality outcomes.

Delivering Beyond Expectations

The result is a 50,000 m² multi-storey car park and transport hub, delivered ahead of schedule and surpassing expectations for finish quality and sustainability.

By combining the best of post-tensioned and precast concrete, this project sets a new standard for fast, efficient, and environmentally responsible infrastructure delivery.