Why Post Tension

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What is Post Tensioning

     Post-tensioning has been used successfully in elevated structures and slab-on-ground foundations for many years. The amount of post-tensioning strand sold has almost doubled in the last 10 years and the post-tensioning industry is continuing to grow rapidly. Today’s residential and commercial construction market is as competitive as it has ever been. Designers, Engineers, Builders and Homeowners alike feel the pressure to control costs – yet not at the expense of high-level performance. The cost benefits from the use of post-tension slabs are achieved by reductions in quantities of concrete and steel, which in turn reduce labor costs. Because beams are smaller and slab thickness are less, a savings in excavation and site preparation are possible.

    For 30 years, the post-tensioning method has strengthened concrete on both small and large projects and has been used successfully in elevated structures and slab-on-ground foundations. Post-tensioning is a method of reinforcing concrete with high strength steel strands, typically referred to as tendons. Post-tensioning offers a perfect balance of two materials that complement each other. Concrete is strong in compression and relatively weak in tension. In contrast, post-tensioning steel has a very high tensile strength, more than three times that of common reinforcing bars. By combining the two, a foundation can resist both compressive and tensile forces caused by various loads, which result in a more efficient and durable concrete foundation.

    Post-tension concrete has proven to be the preferred method of construction for commercial and office buildings, residential apartments, parking structures, as well as single family homes. Owners and Developers who select post-tensioning benefit from longer, thinner slabs, that use less concrete and reinforcement steel which result in greater design flexibility, better crack control and superior structural integrity.


slab

Slab-On-Grade

    Post-tensioning has proven to be an efficient solution for problems associated with ground-supported residential and commercial foundations on shrink-swell soils. This challenge has been met through the integration of post-tensioned foundations for many years. The compressive stresses resist the anticipated tension stresses induced by the soils movement, enhancing the performance over a non-prestressed foundation. Cost benefits are achieved by reductions in quantities of concrete, steel and excavations, which in turn reduce labor costs.   Because of the elimination of stiffening ribs, these foundations can be constructed very rapidly and both labor and equipment to dig the ribs and disposal of excavations are eliminated. This method is a substantial benefit in sandy soils where trenches require shoring.

    Post-tensioned foundations are also used in areas with stable soils to reduce cracking, control deflections by adding stiffness in the slab with less concrete and steel , increase flexural capacity and improve constructability, as well as reduce or eliminate control joints that improves the serviceability and eliminates durability problems. Over all, a post-tension foundation is more economical and provides a better end product than a conventional slab.