Slab-on-Ground
Designers, engineers, builders and homeowners alike feel pressure to control costs – yet not at the expense of high-level performance. This challenge has been met through the integration of post-tensioned foundations for many years.
Post-tensioning has proven to be an efficient solution for problems associated with ground-supported residential foundations on shrink-swell soils. The compressive stresses resist the anticipated tension stresses induced by the soil movements, 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.
In less expansive soils, a uniform thickness foundation is utilized. Typical thickness ranges from 7.5- to 12-inches and any increases in material quantities are compensated by reductions in labor and equipment 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 dispose of excavations are eliminated. This 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, reduce or eliminate control joints, increase flexural capacity and improve constructability. Reducing the control joints also improves the serviceability and eliminates durability problems.
Benefits of post-tensioning for your next slab-on-ground project:
• Stronger/more efficient: Less concrete and steel are needed for the same structural capacity and the slab stiffness is increased so that the slab is better able to resist bending caused by differential soil movements.
• Minimizes and Controls Cracking: Post-tensioning will prevent most cracks from occurring and will keep any cracks that might form tight, reducing water penetration, which can damage flooring and cause mold problems and provide a place of entry for insects.
• Controls deflections: The strength and added stiffness of a post-tensioned foundation reduces the amount the slab will bend under load.
• Faster Installation: With fewer pieces to handle and less concrete to place, a post-tensioned slab can often be installed more quickly than a comparable rebar- or wire mesh-reinforced slab
• More Reliable: An engineered solution, post-tensioning is designed to exacting standards and code requirements, has an excellent performance record and offers increased reliability.
Economical: Cost benefits are achieved by reductions in quantities of concrete, steel and excavation, which in turn reduce labor costs. Beams are smaller and slab thickness is less, therefore savings in excavation and site preparation are possible.
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here to download an informative brochure on post-tensioned residential foundations.