# Girder Strand \[SPIG]

## 3D Reference

Pretensioning strands generally applied to the precast segments. In OpenBrIM, to specify the segments creating a **Support Line** to specify the start and end portions of the segments is beneficial for defining inputs.

**Girder:** Select the girder that strands are applied. Pretension loads are distributed to the this structural element.

**Start Support Line:** Starting support line for the precast segment.

**Offset From Start Support/Insertion Point \[ft]:** Set the longitudinal offset from the **Start Support Line**, if applicable.

**End Support Line:** End support line for the precast segment.

**Offset from End Support/Insertion Point \[ft]:** Set the longitudinal offset from the **End Support Line**, if applicable.

**Strand Row Data:** To view the inputs, click the three-dot menu, then select "Edit…". The description of the inputs is listed below.

| Strand Data                                        |                                                                                                                                                                                      |
| -------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **Type**                                           | Specify the type of the strand Straight or Harped.                                                                                                                                   |
| **Inner strand spacing\[in]**                      | Specify the inner strand spacing. The distance is measured from the center of one strand to the center of the another strand.                                                        |
| **Outer Strand Spacing\[in]**                      | Specify the outer strand spacing between strands. The distance is measured from the center of one strand to the center of the adjacent strand.                                       |
| **Horizontal Offset from Center\[in]**             | Specify the horizontal offset to move center of the strand row.                                                                                                                      |
| **# of Strands**                                   | Specify the number of strands in a single row.                                                                                                                                       |
| **Reference Edge**                                 | Specify the reference edge for **Distance to Reference Edge** input.                                                                                                                 |
| **Distance to Reference Edge @ Start\[in]**        | Set the distance to reference edge. This distance is measured from the **Reference Edge** of the section to the center of the strand. Only avaliable when strand **Type** is Harped. |
| **Harped Distance\[ft]**                           | Distance of the harped location from the start                                                                                                                                       |
| **Distance to Reference Edge @Harped Dist. \[in]** | Set the distance to reference edge. This distance is measured from the **Reference Edge** of the section to the center of the strand. Only avaliable when strand **Type** is Harped. |
| **Debonding Length (Start)\[in]**                  | Specify the debonding length of at the Start of the stra.                                                                                                                            |
| **Debonding Length (End)\[in]**                    | Specify the debonding length at the End of the strands.                                                                                                                              |

![](https://openbrim.atlassian.net/wiki/download/attachments/2226389020/Girder%20Strand.png?api=v2)

![](https://openbrim.atlassian.net/wiki/download/attachments/2226389020/HarpedStrand.png?api=v2)

## Properties

**Material:** Set the material for the strand.

**Wobble Friction Coefficient \[1/ft]:** Pretensioning applications doesn’t include frictional losses that’s why this parameter has default zero value.

**Curvature Friction Coefficient (1/rad):** Pretensioning applications doesn’t include frictional losses that’s why this parameter has default zero value.

## Jacking

**Strand Type:** Enter the strand type for the tendon. The strand type can be imported from the Properties section.

**Jacking Method: Jacking type \[Start/End/Start then End/End then Start]:** Specify the jacking method applied to the strand. Start and End refer to downstation and upstation ends with respect to PGL.

**Jacking Force From Start: applied jacking force to the start of tendon.** Required unless Jacking Method is End-only.

**Jacking Force From End: applied jacking force to the start of tendon.** Required unless Jacking Method is Start-only.

## **FEA Settings**

**Load Dist. Elem. Type\[FENodes/FELines]:** This input affects the type of finite elements loads are distributed. FELines are used for beam elements.

**Percent Loss (%):** Set the percent loss for the long-term losses.

**Show Strand(Detailing)\[No/Yes]:** Controls whether strand polylines are drawn in the 3D detailing view. This is an optional input. Users can leave this input as 0 and let OpenBrIM calculate the long-term losses using the CEB-FIB 1990 curve by running the time-dependent analysis. Alternatively, users can set an approximate value for the Percent Loss (%) to account for long-term losses, which will reduce the Jacking Force values of the tendon.


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