Relative Efficiency of External Prestressing

Abstract

In this paper, the efficiency of tendon profiles is examined for the internal and external prestressing of statically indeterminate structures. The statically indeterminate component of the total prestressing moment is shown to be significant for both parabolic and linear tendon profiles. However, although linear profiles are more effective in counteracting gravity moments in support regions, their efficiency within the spans can be significantly reduced. Therefore, for these profiles, it is more difficult to optimize the effective eccentricity of the prestressing force all along the members. On the other hand, internal prestressing with parabolic tendons offers a more uniform efficiency throughout the structure. Recommendations indicate how localized linear tendons can improve the efficiency of external prestressing.