Setting Tendon Properties

Tendons in ADAPT-Builder have associated properties that can be modified by the user. This section of the help file describes how to modify tendon properties within the Properties Grid.

To edit tendon properties:

  1. Open the Properties Grid panel, if not already opened.

  2. In the model space, select one or more tendons that you want to change the properties for.

  3. The properties that can be modified will display in the properties grid as shown in the following image.

  4. Modify the properties to match the criteria for your design. The different properties that can be set within the Properties Grid are outlined below.

    The identification section of the tendon properties includes the Tendon ID, Label and Group properties. These properties help the program and the user identify and group components.

    The following table provides a description of the properties that can be set.

     

    		 Description

    Identification:

    Tendon ID

    Tendon ID displays the internal tendon id used by the program to differentiate tendons. The tendon ID can not be modified by the user.

    Label

    Label allows you to modify the tendon label of the currently selected tendon(s).

    Group

    Group allows you to set the group the tendons are assigned to as defined in the Visibility>Group Library dialog for display purposes.

    The General section of the tendon properties is where the user can set general properties including the tendon material, drawing mode, and whether the tendon should be considered or disregarded from the analysis of the model.

    The following table provides a description of the properties that can be set.

     

    		 Description

    General:

    Material

    		 Material allows the user to select and assign the post-tensioning material for the tendon. Click the + icon to open the prestressing material dialog window to define or modify tendon materials.

    Direction

    Direction allows the user to define the tendon direction. The available options are:

    • Distributed

    • Banded

    • Undefined

    The user can then use the visibility grid to turn on and off groups of tendons based on the direction property.

    Drawing Mode

    Drawing Mode allows the user to select the mode of the tendon. The available options are:

    • Linear Tendon

    • Spline Tendon

    • Fillet Tendon

    FEM Contribution

    		 FEM Contribution allows the user to either "consider" or "disregard" the tendon from the FEM Analysis.

    Connect to ramp below

    		 Check if the tendon to be modeled should be located in the ramp component when a slab and ramp are overlapping. Uncheck if the tendon should stay at the slab level.

    Reference Plane

    		 Reference Plane allows the user to change the reference plane the tendon is assigned to.

    The Tendon Specification section of the tendon properties is where the user can set the area per strand, tendon/duct height, and number of strands in the tendon.

    The following table provides a description of the properties that can be set.

     

    		 Description

    Tendon Specification:

    Area per Strand

    Area per Strand allows the user to modify the strand area of the tendon.

    Tendon/Duct Height

    Tendon/Duct Height allows the user to define the diameter of the tendon (unbonded) or the diameter of duct (bonded).

    Number of Strands

    Number of Strands allows the user to define the number of strands per tendon. For example, if using a 7-wire strand unbonded cable and you need two cables the number of strands would be set to 2.

    The Stressing section of the Tendon Properties allows the user to define the stressing ends and calculated or effective force option for the tendons. When the Force Option of the Stressing section is set to Effective the user can modify the total and/or effective Force of the modeled tendon. When the Force Option of the Stressing section is set to Calculated the user can enter seating loss and long term loss properties of the tendon used in calculating the friction. elongation. and long-term loss values. Other properties related to the loss calculations can be set per tendon span in the Shape/System/Friction tab of the tendon properties dialog. Please see the Shape/System/Friction section of this help menu for more information.

    Force Option set to Effective:

    Force Option set to Calculated:

    The following table provides a description of the properties that can be set.

     

    		 Description

    Stressing:

    End Stressing

    End Stressing allows the user to set the dead and live ends of the tendon. Available options are:

    • Live, Dead

    • Dead, Live

    • Live, Live

    The input is first end, second end respectively. For the effective force method this is only used as a graphical display of stressing and live ends.

    Force Option

    Force Option allows the user to set the force used for the tendon. The available options and the properties they unlock are as follows:

    • Effective Force

      Effective force design is used primarily in North America. With this method, you define the required post-tensioning force at each location in the floor system, along with the associated tendon profile. Hence, the structural drawings show the final post-tensioning force after all stress losses (effective force) and the tendon profile. The post-tensioning supplier (contractor) can then convert your drawings (structural drawings) to fabrication (shop) drawings, on which the supplier will show the actual number and position of each tendon, together with stressing and elongation values. The value of the force you will use in your design is the force after all losses have taken place. These include friction, seating loss and long-term losses.

      In common building construction, the effective force for unbonded tendons is calculated based on 1,200 MPa (175 ksi) times the tendon area. Note that the force entered in the tendon properties is the product of the effective stress multiplied by the area of each strand. The user also has the option to input the total force in the tendon and the program will calculate and assign to the tendon the equivalent number of strands to accommodate this force.

      The available properties when the Force Option is set to Effective are outlined below.

      Effective Force Set:

      Edit Total Force

      Edit Total Force when checked the Total Force input is unlocked. The user can then input the total tendon force. The program will automatically use the effective force per strand to calculate the number of strands needed to meet that force, and apply that number of strands to the tendon.

      Effective Force

      Effective Force allows the user to input the effective tendon force per strand. Default value is 26.7 kips, 118 kN, or 12.0T and can be modified by the user.

      Total Force

      Total Force allows the user to input the total tendon force of the tendon. he program will automatically use the effective force per strand to calculate the number of strands needed to meet that force, and apply that number of strands to the tendon.

    • Calculated Force

      With variable (calculated) force design, you define the number, location, profile, and stressing of each tendon on your drawings. The program calculates the force immediately after seating of each tendon using the tendon’s geometry, its friction, seating parameters and the jacking force. The forces calculated immediately after stressing are then adjusted for long-term stress losses before being used for code compliance in serviceability and strength requirements .

      To use this option, you must define the friction and stressing characteristics of each tendon. These are defined in the calculated force option set outlined in the table below.

      The available properties when the Force Option is set to Calculated are outlined below.

      Calculated Force Option Set:

      First End Stressing:

      Seating Loss

      		 Distance of strand's draw-in at seating. (in, mm, cm)

      Method

      Each tendon can be stressed at either or both ends. At each end the stressing can be characterized by one of the following manners

      Force Given:

      Force per strand

      		 Defines the effective for a single strand/cable (k,N,T).

      Stress Given:

      Stress

      		 Stress at the first stressing end when stress method is used. (ksi, MPa, t/cm2)

      Jacking Stress:

      Stress/fpu

      		 Jacking stress ratio at the 1st stressing end. Default value is 0.80.

      Last End Stressing:

      Seating Loss

      		 Distance of strand's draw-in at seating. (in, mm, cm)

      Method

      Each tendon can be stressed at either or both ends. At each end the stressing can be characterized by one of the following manners

      Force Given:

      Force per strand

      		 Defines the effective for a single strand/cable (k,N,T).

      Stress Given:

      Stress

      		 Stress at the first stressing end when stress method is used. (ksi, MPa, t/cm2)

      Jacking Stress:

      Stress/fpu

      		 Jacking stress ratio at the 1st stressing end. Default value is 0.80.

      Long-Term Loss:

      Long-Term Loss Option

      Allows the user to define the method use to determine Long-Term Losses. Options are Estimated and Calculated.

      Estimated:

      Long-Term Stress Loss

      		 Defines the assumed Long-Term Loss Estimate. (ksi, MPa, t/cm2)

      Calculated:

      Type of Strand

      		 Defines the type of strand/cable as low-lax or stress-relieved.

      Concrete Age

      		 Defines age of concrete at stressing for loss calculations. (days)

      Modulus of Elasticity

      		 Defines the elastic modulus of concrete at stressing for loss calculations. (ksi, MPa, T/cm2)

      Relative Ambient Humidity (RH)

      		 Defines the Relative Humidity for shrinkage loss calculations. (%)

      Volume to Surface Ratio (V/S)

      		 Defines the Volume to Surface ratio (in., mm., cm.) for loss calculations.

      Initial Precompression

      		 Defines the average initial precompression (ksi, MPa, T/cm2) for loss calculations.

      Ultimate Creep Coefficient

      		 Defines the Ultimate Creep Coefficient for use in the loss calculations.

      All Strands Stressed

      		 Defines if tendons are stressed at one time for elastic shortening calculations.

    The Offsets section of the tendon properties is not used and can not be accessed. The location of the tendon is referenced from the slab/beam/ramp the tendon is modeled in.

    The Plan Coordinates (X, Y) section of the tendon properties lists the coordinates of the verticies (end/high points) along the tendon. Modify the coordinates to modify the location of the tendon on plan.

    In the Appearance section of the tendon properties the user can modify the thickness of the tendon and it's text, the drawing layer the tendon is located on and the color of the tendon.

     

    		 Description

    Appearance:

    Layer

    Layer allows the user to modify the drawing layer the tendon is on. Pick the new layer from the drop down list.

    Line Thickness

    Line Thickness allows the user to increase or decrease the line thickness of the tendon on plan.

    Text Thickness

    Text Thickness allows the user to increase or decrease the thickness of the tendon fonts.

    Outline Color

    Outline Color allows the user to modify the color of the tendons on screen. Choose the new color from the color palette.

     

  5. Repeat steps 2 - 4, until all tendons have the correct properties set for the design.