One of the methods with the possibility to prevent not acceptable deflections in concrete structures is a pre-stressing. For the pre-stressing can be used a high strength steel (FeP1570, FeP1670, FeP1770, FeP1860) strands combined into tendons.
The input format for tendons is: number_of_tendons S diameter_of_tendon. For example, 10S7.5 means that the structural element has 10 tendons and diameter of each tendon is 7.5 mm. The pre-stressed reinforcement can be provided in the tab Pre-stress of the Concrete Cross section Check window.
The concrete strength at the moment of applying pre-stress f'ctk,t and the distance from the reinforcement till the surface of the element dp must be provided in this window.
The results of the performed checks will be shown in the tooltips of the last two columns as well as in the corresponding reports.
The external loads for the procedure of the pre-stress modelling will be generated on the base of the provided initial data about parameters of initial pre-stressing. The load values will be represented in the Loads Calculation window. Two separate load cases: Initial prestress and Acting prestress will be generated.
The special load combinations will be generated. These combinations are used for modelling actions induced by the initial prestress. It is allowed taking into account the influence of the early creep on value of the acting prestress and deflections.
This procedure can be started and performed automatically by pressing 
in the Concrete toolbar.