Constraint Forces From Imposed Deformations

In statically indeterminate systems, imposed deformation generally cannot set freely. In order to achieve the deformation compatibility, constraint forces are required. From this, it can be deduced that the constraint forces for a given deformation are dependent on the stiffness of the system. The greater the stiffness, the greater the internal constraint forces. For this reason, constraint forces in reinforced concrete structures are generally worth mentioning and must be taken into account in the design. The accurate development of a constraint force depends on numerous factors. These are mainly the stiffness distribution over the length, stiffness of the cross section, ductility of the reinforcement and creep ability of concrete. To gain more information about the real behavior, experiments were carried out on reinforced concrete beams and prestressed beams.