Tendon Definitions Dialog Box

The Tendon Definitions dialog box allows you to define the layout, properties, and jacking forces to be used for post-tension tendons. To open this dialog box, click the Tendons button on the Model tab. To define the list of tendons available in this dialog box, open the Tendon Library.

Adding Tendon Definitions

Each girder may contain any number of tendons. In addition, the full section may have any number of tendons. The effect of the tendons that are defined for the full section will be evenly distributed among the individual girders. Conversely, the effect of the tendons that are defined for an individual girder will be distributed to the full section. These distributed tendons are automatically generated by CIP RC/PT Girder and cannot be edited directly by the user.

Perform the following steps to add a tendon definition:

Select the girder section you want to modify from the drop-down menu located in the Girder field.
In the Tendon Definitions grid, select the definition you want to add to by clicking anywhere in its row. A blue arrow displays on the left side of the grid to mark the selection.
Click the Add Tendon button. This adds a new definition after the selected one.
Enter the tendon definition values in the grid. A definition for each parameter is available below.

Deleting Tendon Definitions

Perform the following steps to delete a tendon:

Select the girder section you want to modify from the drop-down list located in the Girder field.
In the Tendon Definitions grid, select the definition you want to delete by clicking anywhere in its row. A blue arrow displays on the left side of the grid to mark the selection.
Click the Delete Tendon button to remove the selected tendon.

Copying to All Girders

In many cases, several similar tendons exist in all girders. The Copy to All Girders command is used to create a duplicate of the selected tendon in every girder to simplify the definition of similar tendons.

Perform the following steps to copy a tendon definition to al other girders:

Select the girder that contains the desired tendon you want to copy from the drop-down list located in the Girder field.
In the Tendon Definitions grid, select the tendon you want to copy by clicking anywhere in its row. A blue arrow displays on the left side of the grid to mark the selection.
Click the Copy to All Girders button. This copies the selected tendon to every girder.

Adding Path Nodes

Each tendon may have a general or a standard path. The shapes of standard paths are defined by the number of spans, and are made of parabolic pieces.

The general paths are made of a number of segments (subpaths) connected to each other. Adding a node that signifies the end of the subpath creates each subpath. The general path may contain any number of subpaths.

Perform the following steps to add a path node:

Select the girder section you want to modify from the drop-down list located in the Girder field.
In the Path Node grid, select the path you want to add to by clicking anywhere in its row. A blue arrow displays on the left side of the grid to mark the selection.
Click the Add Path Node button. This adds a new path after the selected one.
Enter the path node values in the grid. Whenever a hinge is added, the bridge gets sub-divided into "Hinged" segments - e.g. one hinge creates two hinged segments, two hinges create three hinged segments. Whenever "Hinged" option is selected a tendon is automatically added to the segment specified in the Hinged column.

Deleting Path Nodes

Deleting a path node deletes the subpath that leads to that node. If the Use Percent option is checked, then the previous subpath stretches to fill the void. If it is not checked, then all the following subpaths move back to fill the void, and the path becomes shorter in length.

Perform the following steps to delete a path node:

Select the girder section you want to modify from the drop-down list located in the Girder field.
In the Path Node grid, select the path you want to delete by clicking anywhere in its row. A blue arrow displays on the left side of the grid to mark the selection.
Click the Delete Path Node button to remove the selected path.

Using Percent

The path node locations (subpaths) can be specified by an absolute distance or by a location as a percent of span length.

Setting

Description

Checked

Setting	Description
Standard Path	Locations of low points are based on the percent of their respective spans.
General Path	Location of each node is at the percent of span length for the selected span, relative to start of span.

Not Checked

Setting	Description
Standard Path	Locations of low points are based on distance from previous point (i.e., high points, or start of bridge). The high points are always set to the center of the pier.
General Path	Location of each point is specified as a distance from the previous point.

Calculating Horizontal Curvature Losses

If this option is selected, LEAP®CIP RC/PT Girder uses the bridge alignment information to calculate the radius of curvature and the length of curve along the bridge and its effect of the friction loss.

Tendon Definitions

Setting

Description

Girder

The girder to which the tendon applies.

Name

Enter a unique ID name to identify the tendon.

Span Type

Select the span type from the drop-down list. The span type is either standard or general. The standard path is based on the number of spans in the bridge. Spans are defined as the distance between supports (piers or abutments) except that the first span is defined as starting at the BB and the last span ends at the EB. A general path can be made of a combination any number and type of subpaths. Each subpath can be linear, parabolic, or double-curvature. Tendon types are based on the list of tendons defined in the tendon library.

Tendon Type

Select the tendon type name from the drop-down list. The tendon type name refers to a tendon material definition loaded from the Tendon Library. Tendon material definitions include specification of: material type, yield stress (fpy), ultimate stress (fpu), modulus of elasticity, diameter, and area. This library can be found by selecting Tendons from the Libraries. menu. Tendon type definitions must be added and deleted from the tendon library. An additional tendon type "unknown" is provided. Use the "unknown" type to eliminate the limits on jacking forces while designing the P Jack.

LS Losses

Enter the total lumped sum losses.

Friction Coeff

Enter the friction coefficient.

Wobble

Enter the wobble coefficient.

Calc Relax

Click to either automatically calculate the relaxation value or manually enter the value.

Relax

In the case of "user-defined," enter a predefined relaxation stress value.

PJack Type

Select the jack type from the drop-down list.

Setting	Description
Left	Identifies the jacking from left end (start of bridge).
Right	Identifies the jacking from right end (end of bridge).
Both	Identifies the jacking from both ends (first start, and then end of bridge).

PJack Unit

Click to choose to enter P Jack as a percentage of fpu or as a force.

PJack Lt

If jacking from the left or both. Enter the P Jack percentage or force value. This value must be between 55% and 100% of the tendon fpu unless the "unknown" tendon type is used in which case the jacking force can be any value.

PJack Rt

If jacking from the right or both. Enter the P Jack percentage or force value. This value must be between 55% and 100% of the tendon fpu unless the "unknown" tendon type is used in which case the jacking force can be any value.

Lt Anchor Set

If jacking from the left or both. Enter the anchor set distance at left.

Rt Anchor Set

If jacking from the right or both. Enter the anchor set distance at right.

Path Nodes

Setting	Description
Location	Lists the sequence number for reference.
Span Number	Enter the span number for this point.
Distance (%)	Enter the distance of this point relative to previous point (Distance), or the start of span (%).
Top or Bottom	Determine whether the offset is measured from top or bottom of section.
Depth	The cross section depth (non-editable).
Offset	Enter the offset for tendon location.
Variation Type	The variation type can be linear, Par-S (parabolic with zero slope at the start), Par-E (parabolic with zero slope at the end), or Par-D (double curvature made of two parabolas with matching slope at the point of contraflexure).
POC	Identifies the location of point of contraflexure for a double curvature subpath as the ratio of its distance from the start of subpath to the length of the subpath.

Technical Discussion

When the Use Percent check box has been selected LEAP®CIP RC/PT Girder will automatically adjust the horizontal location of all subpath control points based upon the current span distances. Spans are defined as the distance between supports (piers or abutments) except that the first span is defined as starting at the BB and the last span ends at the EB.

A Standard span type tendon automatically locates horizontally its' starting point to be located at the beginning of the bridge or girder. Additionally, a "high" point is horizontally located at the centerline of every bridge pier and the tendon ending point is located at the end of the bridge or girder. These points are automatically adjusted horizontally byCIP RC/PT Girder whenever the user changes the component layout and cannot be adjusted manually by the user. This is true whether the user has selected Use Percent for entering subpath data or has entered control points by distance. The user does have control over the vertical position of all control points and the horizontal position of the "low" points.

The user has complete control over both the horizontal and vertical location of the subpath control points for a General span type tendon although CIP RC/PT Girder will adjust the horizontal location automatically if the user has selected Use Percent.