Post-tensioning is a method of reinforcing concrete, used extensively in the construction and refurbishment of bridges.
High-strength steel tendons are positioned in ducts or sleeves before the concrete is placed. Once the concrete has gained strength, tension is then applied, pulling the tendons and anchoring them against the outer edges of the concrete, before service loads are applied.
Freyssinet’s founder Eugene Freyssinet successfully developed pre-stressed concrete in the 1930s, after recognising that placing concrete under compression greatly increased its strength.
Freyssinet has been a pioneer of post-tensioning and stay cable technology in the UK since 1948, when the first bridge using Freyssinet cables and anchorages was built.
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Post-tensioning
For nearly 70 years, Freyssinet has been at the forefront of post-tensioning innovation, and now offers cutting-edge PT systems combining high performance and durability.
Freyssinet prestressing anchors are available in types C and F and have been installed in structures all over the world.
Post-tensioning technology has been applied to:
- Bridge decks and piers
- Nuclear containment vessels
- Liquefied natural gas (LNG) storage tanks
- Offshore platforms
- Wind turbine towers
In 2014, following the successful completion of Phase 1, Freyssinet was appointed to provide further specialist repair works to Hammersmith Flyover in London in Phase 2. The project was the UK’s first and most significant full post-tensioning replacement and Freyssinet developed a number of different innovative methods in order to facilitate the complex requirements of the project. Subsequently, Freyssinet has received a number of awards for the techniques, innovations and applications used on the project, including the Equipment and Tools award at VINCI 2015 Innovation Awards UK and Ireland region.
Stay cables
Freyssinet is a world leader in bridge stay cables, having developed cable technology which delivers superior fatigue resistance, corrosion protection, ease of inspection and ease of replacement.
Freyssinet offers two types of stay cable:
HD stay cables
Freyssinet invented the multi-strand HD stay cable, a robust and flexible cable suitable for long span structures. As each strand is independent, they can be installed and tensioned individually. The standard range of HD stay cables varies from 1 to 169 strands; however there is no limit to the capacity or length of the cable.
H1000 stay cables
Freyssinet H1000 stay cable is a parallel strand system for use in small or light structures, such as hangers for foot bridges, arch bridges and suspended roofs.
Freyssinet bridges services include:
- Post-tensioning
- Concrete repairs
- Stay cable bridges
- Bridge bearing replacement
- Bridge expansion joints
- Dampers/STU
- Cathodic protection
Case Studies
Pre-stressing Upper Forth Crossing, Kincardine
Second Severn Crossing Cable Stay Bridge