The most dramatic example of design flexibility is demonstrated by the use of post tensioning for bridges where it allows very demanding geometry requirements, including complex curves, variable super elevation and significant grade changes. The use of post-tensioning promotes a more environmentally friendly approach to construction.
In the first place, post-tensioned structures feature less construction materials steel reinforcement, concrete and thus create fewer carbon emissions in terms of production and transportation. 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.
