Analysis of presress

 In pre-stressed structural elements, stretched tendons are placed inside concrete. The tensile stresses of the tendons are transferred to concrete in the form of compressive stresses (due to bond between tendons and concrete in the case of pre-tensioned elements and through end anchorages in the case of post-tensioned elements). These forces are generally axially transferred in concrete as shown in =Figure. Here, the pre-stressing force is shown to be applied at the location of centroidal axis of the member (i.e. concentrically applied), as the tendon has been placed at the centroidal axis.