Is it true that there are special requirements for the formwork for prestressed concrete?
The ACI Standard Specifications for Structural Concrete for Buildings (ACI 301-72) requires that formwork for prestressed concrete "shall not restrain elastic shortening, deflection or camber resu Iting from application of the prestressing force. " It also provides that "form supports shall not be removed until sufficient prestressing force has been applied to support the dead load, formwork and anticipated construction loads. When a structure is prestressed in two directions formwork shall support the load which is redistributed by the partially completed stressing operation." Formwork must be rigid enough to prevent prestressing tendons from being displaced beyond specified tolerances, according to the same Standard.