Q. What are the Parasitic forces for prestressing?
In statically determinate structures, prestressing forces will cause the concrete structures to end upwards. Therefore precambering is generally carried out to counteract such effect and make it more pleasant in appearance. Though for statically indeterminate structures the deformation of concrete members are restrained by the supports and consequently parasitic forces are developed by prestressing force in addition to bending moment produced by eccentricity of pre stressing tendons. The developed forces at support modify the reactions of concrete members subjected to external loads and generates secondary moments (or parasitic moments) in the structure.