Prestressed concrete was invented by Eugène Freyssinet in 1928. It is a method for overcoming concrete's natural weakness in tension. It can be used to produce concrete panels, beams, floors or bridges with a longer span than is practical with ordinary reinforced concrete.
Concrete has one major weakness, it cannot resist tension well. It is extremely good for arches, but not very good for beams. There is a solution to this problem which is to design the structure so that tension cannot occur in the concrete.
Prestressed concrete is cast around already tensioned wire or strand. This method produces a good bond between the tendon and concrete, which protects the tendon from corrosion and allows the direct transfer of tension. The cured concrete adheres and bonds to the strand and when the tension is released it is transferred to the concrete as compression by static friction. However, it requires stout anchoring points between which the tendon is to be stretched and the tendons are usually in a straight line. Thus, most prestressed concrete elements are prefabricated in a factory and must be transported to the construction site, which limits their size. Prestressed elements may be concrete panels, balcony elements, lintels, floor slabs, beams or foundation piles.
Please visit our prestressed concrete panels page for more information.