Fabriksförspänning

Fabriksförspänning, a Swedish term, translates to "factory prestressing" or "pre-tensioning" in English. It refers to a method used in concrete construction where steel tendons are tensioned before the concrete is poured. Once the concrete has hardened around the tensioned steel, the tension is released. This action creates a compressive force within the concrete, which counteracts the tensile stresses that will occur when the element is subjected to loads.

The process typically involves anchoring the high-strength steel tendons to a strong abutment or a specialized rig. These tendons are then stretched to a predetermined tension. Concrete is then cast into the formwork around the tensioned tendons. After the concrete reaches a sufficient strength, the tendons are cut or released from their anchors. The stored elastic energy in the tendons is transferred to the concrete as compression.

Fabriksförspänning is commonly employed for manufacturing precast concrete elements such as beams, slabs, bridge girders, and piles in a controlled factory environment. This method allows for the production of longer, thinner, and stronger concrete members compared to conventionally reinforced concrete. It also enables efficient mass production and ensures consistent quality due to the controlled manufacturing conditions. The resulting prestressed concrete elements exhibit enhanced durability and load-bearing capacity.