Post-tensioning Association

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Welcome to the Post-Tensioning Association.

The objectives of the Association are:
  • To promote the use of post-tensioning in buildings, bridges, silos and tanks, ground floor slabs and other structural types throughout the UK construction industry.
  • To promote best practice in the design, procurement and execution of post-tensioned structures.
  • To support and take part in research and development to improve the efficiency and technical capabilities of post-tensioning.
  • To support high quality in PT construction through the CARES QA scheme and other relevant bodies
  • To support safe working practices throughout the UK PT industry and to maintain high levels of training.
Membership of the Association is open to companies directly engaged in the manufacturing and/or installing of post tensioning materials and/or the design of post tensioned structures in the United Kingdom which share our beliefs. Contact the Chairman for more information.
What is Post-Tensioning?
Concrete is strong in compression but relatively weak in tension. One way to overcome this shortcoming is to impose a field of compressive stress on the member so that even under maximum loading the member is still in compression, or limited tension. This is referred to as Prestressed Concrete as stress is deliberately imposed prior to the member being put into use.
There are two common ways of prestressing concrete; by pre-tensioning or by post-tensioning. With pre-tensioning, the tendons are stressed before the concrete is placed. The tendons are stretched between strong bulkheads which withstand the forces and the concrete is poured around them. This system is most frequently adopted in precasting yards.
Post-tensioning involves stressing the tendons after the concrete has been placed and cured. The tendons are cast into ducts or sleeves to allow the strand to slide through the hardened concrete and corrosion protection is normally provided by injecting cement grout or grease. Post-tensioning is used in bridges, floor slabs, silos and many other forms of construction. It can bring significant benefits in terms of economy, construction programme, structural performance and reduction in material usage.

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Nadarajah Surendran

PTA Chairman