Click the Design Parameters button to activate the Design Parameters dialog box; it defaults to the Permissible Stress tab, as shown in Figure below.

You can modify the limiting stress values by typing over the default values or have the program use the default stress factor values to calculate the limiting stresses by selecting the Use Factor To Calculate check box. Notice that when this check box is selected, the text boxes become grayed out, returning to the default values.

IRC Codes SP71-2000 specify stress limits for concrete; specifically, pre-tensioned concrete components. Tensile and compressive stress limits are specified for fully prestressed components for two stages of the Service Limit State -- at release and after final prestress losses with all super imposed dead and live loads applied.

Precast/Prestressed Girder, by default, only checks the stress limits for the top and bottom fibers of precast, prestressed concrete girders. Optionally, the user may elect to also check the stresses at the top fiber of the cast-in-place, reinforced concrete deck.