DIE WIRTSCHAFTLICHKEIT ALS EIN KRITERIUM ZUR WAHL DES VORSPANNGRADES.

The influence of the prestress degree on the costs can be represented graphically by the suitable definition of cost-parameters of a partial prestressed structural member, independent of the absolute values of costs. By these curve tables the planning engineer will be able to determine quickly the economy of the prestress degree, as well as to calculate the influence of an increase or decrease of the prestressing degree on the costs. As a rule, minimum costs are found with medium prestress degrees ranging from 0. 3 to 0. 7, depending on the type of structural member and cost-parameters. However, it has to be emphasized that costs are not the only criteria when selecting the degree of prestressing. Other technical criteria such as deflection, stiffness or water tightness can be relevant.