The following expressions are applied for Class 1 (Ordinary), Class 2 (Low) and Class 3 (Hot rolled) to calculate relaxation loss with time. : yield stress (0.1% Offset Yield Stress)Ĭ: Relaxation Coefficient (general steel: 10, low-relaxation steel: 45) Losses due to steel relaxation are determined from the following equation: Relaxation coefficients of 10 and 45 may be used for general steel and low-relaxation steel respectively. Select 10 or 45 for Relaxation Coefficient (C), which relates to the product.
The diameter of the strand is used to compute Transfer Length. The program automatically calculates the diameter of strand corresponding to the specified Total Tendon Area. Strand Diameter When the Tendon Type is Pre-Tension, the diameter of strand should be entered. Based on the tendon area, the duct diameter is automatically calculated, which is then referred to for duct diameter input. You may either directly specify the cross-sectional area or click to enter the standard cross-sectional area and the number of strands for auto-calculation of the total area.ĭuct Diameter When the Tendon Type is Post-Tension, input for the diameter of duct is required. In practice, the self weight of reinforcement including tendons is taken into account by increasing weight density of concrete. Weight density of tendon is not taken into account in the calculation of self weight because tendon is considered as equivalent loads rather than elements. For pre-tension type tendon, consider the elastic deformation loss due to axial force and moment acting on the tendon.
Click to the right to add new or modify/delete previously defined tendon properties. Select the material properties of the tendon. If the tendon placement location is External, the tendon is displayed as a straight line in Display. Internal (Post-Tension): Post-tensioning tendons through hardened concrete members - tendons are gradually stressed and anchored to the members.Įxternal: Tendons are placed external to concrete members and stressed.ĭepending on the Tendon Type ( Pre-Tension, Post-Tension and External), the entry fields for variables related to tension losses in tendons and duct diameter are either activated or inactivated. Internal (Pre-Tension): Prestressing tendons prior to casting concrete, which transmits prestress through bonding between concrete and tendons To define new or additional tendon propertiesĬlick in the Tendon Property dialog box and enter the following:ĭefine the tendon type among Pre-Tension, Post-Tension and External. Define the tendon properties such as tendon area and instantaneous prestress losses.įrom the Main Menu select Load > Temp/Prestress > Tendon Property.
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