Post-tensioning strengthens concrete by applying controlled force through high-strength steel tendons. Post-tensioning is a technique used to strengthen concrete by applying tension to steel tendons after the concrete has hardened. First, ducts or sleeves are placed within the concrete formwork before pouring. High-strength steel strands or bars are threaded through these ducts. Once the concrete gains sufficient strength, hydraulic jacks are used to tension the tendons, pulling them tightly. The tendons are then anchored at the ends, transferring compressive force into the concrete. This counteracts tensile stresses, minimizes cracking, and allows for longer spans with thinner slabs. Post-tensioning is widely used in bridges, buildings, and industrial structures, enhancing both durability and efficiency while reducing material usage. video rights : Respective owners DM for removal/credits #posttensioning #prestressing #concrete #construction #bridge #civilengineering #civilconstruction #engenharia #engenhariacivil #engenheiro #engenheiro #civilengineer #qualityengineer
▶️ Execution steps 1. Installation of ducts and sleeves before concreting. 2. Pouring of concrete around the ducts and anchorages. 3. Curing of the concrete until it reaches sufficient strength (usually ≥ 25 to 30 MPa). 4. Insertion and stressing of the strands with the jack: ▪︎The jack pulls the cable. ▪︎The anchorage locks the tension. 5. Grouting of the duct → completion of the operation.
A protensão "in loco" é um trabalho meticuloso. Em vãos extensos a correta instalação das bainhas é crucial para o sucesso da operação.
My 1st site project, the Greenford Flyover A40, back in 1978 was prestressed, post tensioned. Each span was tensioned individually, great memories. The system was used for 2 bridges I helped construct on the M25, but the concept was changed to pre-tensioned beams and then steel thereafter.
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This is a fantastic and clear breakdown of a critical engineering technique. You've perfectly articulated why post-tensioning is a game-changer in modern construction—it allows for longer spans with thinner slabs, all while minimizing cracking and enhancing durability. It's a prime example of how applying controlled force can create more efficient, resilient, and sustainable structures.
Wow
Just an addition to the above explaination: Post tentioning could be done either on one end or both ends as desired by structural engineer (designer). The steel is tentioned to a certain limit only (given by designer), an airduct at appropriate places has to be provided in order to fill it with appropriate grout.
I love producing precast elements
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5dUma verdadeira engenharia de precisão. O pós-tensionamento é mais do que uma técnica, é uma revolução silenciosa na forma como projetamos estruturas resistentes, eficientes e duráveis. Ao aplicar força controlada após o endurecimento do concreto, conseguimos neutralizar tensões internas, reduzir fissuras e otimizar o uso de materiais. 🔹 Menos espessura, mais resistência. 🔹 Menos peso, mais desempenho. 🔹 Mais segurança, mais sustentabilidade. É por isso que pontes, edifícios e estruturas industriais confiam nesta solução: porque ela transforma concreto em inteligência estrutural. Engenharia que pensa, tensiona e protege.