What are precast concrete arches?
Precast concrete arches are prefabricated, modular structures assembled on site to form tunnels, bridges, and crossings—delivering fast installation, high load capacity, and long-term performance.
Precast Concrete Arches: Smarter Infrastructure, Built Faster
Precast concrete arches—like Geoquest’s TechSpan® system—are transforming how tunnels, underpasses, and crossings are delivered across transport, mining, and water infrastructure.
Using engineered precast segments, these structures install quickly and perform efficiently, working with surrounding soil to create a strong, resilient system.
Designed for high performance, Geoquest’s precast arches can support high fill heights and heavy live loads, including mining vehicles, rail traffic, and major road infrastructure.
Read our technical paper – TechSpan® precast concrete arches
Why are precast arches gaining traction?
- Fast installation
Modular construction reduces programme time and disruption. - Lower site impact
Minimal excavation, formwork, and on-site labour. - Structural efficiency
The arch shape transfers loads in compression, improving performance. - Custom design flexibility
Geometry is tailored to each project’s loading and clearance requirements. - Durability and long life
Designed for a 100-year lifespan with minimal maintenance.
Where are precast arches used?
- Road and rail tunnels
- Bridge underpasses and overpasses
- Mining haul road crossings
- Culverts and flood infrastructure
- Pedestrian and wildlife crossings
FAQs Overview
What span, length, or width can precast arches achieve?
Precast arches are highly flexible. Spans range from small culverts to 20m+ openings, with structure length extended by placing segments end-to-end.
Are they available as one-piece or multi-piece systems?
Yes. TechSpan® arches can be supplied as single-piece arches or two-piece (half-arch) systems that meet at the crown, depending on transport and site constraints.
How long do precast concrete arches last?
They are engineered for long service life (often 100 years or more), using durable materials and efficient structural design to minimise maintenance.
Can they handle heavy loads?
Yes. Precast arches are designed to carry heavy live loads and high embankments, including mining vehicles, rail traffic, and high-volume road infrastructure.
Can they be installed in live environments?
Yes. They can be installed over active roads, rail, or waterways with minimal disruption to ongoing operations.
Spotlight: TechSpan® precast arches in action
The South32 Quindanning Mine Enabling Infrastructure project in Western Australia marked a major milestone with the installation of a TechSpan® precast concrete arch bridge over Pinjarra-Williams Road.
Designed and manufactured by Geoquest and constructed by Georgiou, the structure is one of the largest of its kind in the Southern Hemisphere:
- 21m span — among the largest precast arches in the Southern Hemisphere
- Installed in just two days on a remote WA project
- Designed for heavy mining loads and high fill conditions
One-piece vs Two-piece Arch Span
What span can a one-piece precast arch achieve?
One-piece precast arches are used for smaller spans up to 14 metres.
When is a two-piece arch used instead?
Two-piece concrete arches can be used for up to circa 21 metre spans. .
Why not use one-piece arches for larger spans?
As spans increase, single units can become difficult to transport and lift. Dividing the arch into segments enables:
- Practical delivery to site
- Safe lifting and installation
- Flexibility for large infrastructure projects
Quick takeaway
- One-piece = smaller spans, simplified install
- Two-piece = larger spans, greater flexibility
The bottom line
Precast concrete arches combine speed, flexibility, and long-term durability—making them a go-to solution for infrastructure projects where performance, efficiency, and lifespan matter most.
For more information on the Geoquest TechSpan one-piece precast concrete arch or two-piece concrete arch systems contact your local Geoquest Australia & New Zealand office.
