# Diaphragm X (w/o Top Chord) \[SPIG]

## Location

**Girders:** Choose the two girders that are connected by the diaphragm x.

**Skew Angle:** A positive skew value rotates the diaphragm x in a clockwise direction, while a negative skew value rotates it in a counterclockwise direction. It is important to remember that the diaphragms are positioned at the specified station along a line perpendicular to the PGL, which is then rotated according to the entered skew value.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-115708.png?api=v2)

**Station \[Start/End]:** Define the station either using the options Start/End or by entering the station along the PGL.. When dealing with curved girder bridges, collecting distance along the girder length can lead to different inputs for the right and left girder that are connected by diaphragm, causing ambiguity. Therefore, collecting the station along the PGL is a more reliable solution to avoid such issues. Furthermore, since diaphragms are typically continuous in the transverse direction, entering the same station for all diaphragms ensures that their locations are consistent between each girder.

The same principle can be applied for skewed diaphragms. If the user enters the same station and skew values for the diaphragms between Girder 1-2, Girder 2-3, and Girder 3-4, it ensures continuity between the diaphragms. It should also be noted that the diaphragms are positioned along a line perpendicular to the PGL, which is rotated according to the entered skew value.

Inaccurate finite element models and disconnected nodes/elements in the diaphragm can occur if the entered station values are not >= the girder start station or <= the girder end station. This can cause stability issues in the finite element model. To ensure correct station input, users should select the start/end options from the station input. This approach is especially recommended for diaphragms located at the beginning or end of girders.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-124107.png?api=v2)

## Sections

**Bottom Chord Section:** Assign a section for the diaphragm's bottom chord section.

**Diagonal Chord Section:** Assign a section for the diaphragm's diagonal chord section.

## Stiffener

**Vertical Stiffener Thickness:** The thickness value of the Vertical Stiffener element can be defined here.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-130256.png?api=v2)

**Vertical Stiffener Width:** The width value of the Vertical Stiffener element can be defined here.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-125259.png?api=v2)

**Vertical Stiffener Depth:** The depth value of the Vertical Stiffener element can be defined here.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-125617.png?api=v2)

**Vertical Stiffener Offset from Top:** The parameter represents the offset amount taken from the top flange boundary of the girder for the vertical stiffener object.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-131354.png?api=v2)

**Vertical Stiffener Offset from Girder Web Center:** The parameter represents the offset amount taken from the web center boundary of the girder for the vertical stiffener object.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-132338.png?api=v2)

## Geometry

**Diag. Chord Offset from Top:** The parameter represents the offset amount taken from the side boundary of the vertical stiffeners for the top of diagonal chord objects.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-134708.png?api=v2)

**Diag. Chord Offset from Bottom:** The parameter represents the offset amount taken from the side boundary of the vertical stiffeners for the bottom of diagonal chord objects.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-141001.png?api=v2)

**Diag. Chord Vert. Offset from Top Edge of Section:** The parameter represents the offset amount taken from the top flange boundary of the girder for the top of diagonal chord objects.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-141629.png?api=v2)

**Diag. Chord Vert. Offset from Bottom Edge of Section:** The parameter represents the offset amount taken from the bottom chord of the diaphragm for the bottom of diagonal chord objects.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-142341.png?api=v2)

**Bot. Chord- Vert. Dist. from Bottom Edge of Section:** The parameter represents the offset amount taken from the bottom of diagonal chord of the diaphragm for the bottom chord object.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-142802.png?api=v2)

**Bot. Chord- Horz. Distance from Center of Web:** The parameter represents the offset amount taken from the side boundary of the vertical stiffeners for the bottom chord object.

![](https://openbrim.atlassian.net/wiki/download/attachments/2310013243/image-20231121-143744.png?api=v2)

## Quantities

**Diagonal Chord Material (Read-Only):** Material assigned to the diagonal chord, derived from the selected section (Read-only).

**Diagonal Chord Section (Read-Only):** Section name assigned to the diagonal chord (Read-only).

**Bottom Chord Material (Read-Only):** Material assigned to the bottom chord, derived from the selected section (Read-only).

**Bottom Chord Section (Read-Only):** Section name assigned to the bottom chord (Read-only).


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