Prestressed Concrete

Prestressed concrete is a civil engineering construction method in which internal steel tendons are tensioned, either before the concrete is poured or after it has cured, so that the concrete is placed under a permanent compressive stress that counteracts the tensile stresses it would otherwise experience under load. Because plain concrete is strong in compression but weak in tension, this pre-compression lets a prestressed concrete member span longer distances and carry heavier loads with less material than conventionally reinforced concrete. Developed commercially by French engineer Eugene Freyssinet in the 1920s and 1930s, the technique became widely used for bridges, parking structures and long-span floor systems.