# Cross-frame X \[PIG] ## Location **Girders:** Choose the two girders that are connected by the cross frame. **Skew Angle:** A positive skew value rotates the cross frame in a clockwise direction, while a negative skew value rotates it in a counterclockwise direction. The cross frames are positioned at the specified station along a line perpendicular to the PGL, which is then rotated according to the entered skew value. **Station \[Start/End]:** Enter the station along the PGL, or select the **Start** / **End** option. Using the PGL station keeps cross frames continuous transversely across the bridge and avoids ambiguity from different along-girder distances on curved bridges. For cross frames at the very beginning or end of the girder span, use the Start/End options to prevent disconnected nodes in the FEM. **Has Middle Gusset Plate? \[YES/NO]:** Choose YES if there is a gusset plate at the crossing point of the two diagonals. When YES, a node is generated at the diagonal intersection, and the **Center Gusset Plate** and its offsets become editable. **Chord Flipping Side \[Back Station/Ahead Station]:** Controls on which side of the perpendicular line the diagonals and gusset plates are oriented. Flip the side when the default layout places the diagonals opposite to the detailing drawings. ## Sections Assign a section for the top, bottom, or diagonal chord, imported from the AISC database. The section data drives both the 3D model and the Finite Element Analysis (FEA). **Top Chord \[YES/NO]:** Activates the Top Chord. When NO, the top chord members and their related sections are omitted. **Bottom Chord \[YES/NO]:** Activates the Bottom Chord. **Diagonal Chord \[YES/NO]:** Activates the Diagonal Chords. **Top Chord Section:** Assign a section for the top chord. **Bottom Chord Section:** Assign a section for the bottom chord. **Diagonal Chord Section:** Assign a section for the diagonal chords. **Top Chord Orientation Angle \[0/90/180/270]:** Specify a rotation angle around the longitudinal axis of the top chord. **Bottom Chord Orientation Angle \[0/90/180/270]:** Specify a rotation angle around the longitudinal axis of the bottom chord. **Diagonal Chord Orientation Angle \[0/90/180/270]:** Specify a rotation angle around the longitudinal axis of the diagonal chord. **Top Chord Material:** Material assigned to the top chord (Read-only; derived from the assigned section). **Bottom Chord Material:** Material assigned to the bottom chord (Read-only; derived from the assigned section). **Diagonal Chord Material:** Material assigned to the diagonal chord(s) (Read-only; derived from the assigned section). ## Geometry These parameters are used both for computing the member-end offsets of the truss elements in the finite element analysis and for the 3D model. **Top Chord- Vert. Dist. of WP from Top of Girder:** Vertical distance between the working point (WP) of the top chord and the top of the precast girder. Affects both 3D and FEM. **Top Chord- Horz. Dist. of WP from Center of Girder:** Horizontal distance between the WP of the top chord and the girder centerline. Affects both 3D and FEM. **Top Chord- Inner Offset from WP:** Inner offset of the top chord's working point along the chord's longitudinal axis. Affects both 3D and FEM. **Dia. Chord- Top Vert. Dist. of WP from Top of Girder:** Vertical distance between the diagonal chord's top WP and the top of the precast girder. Affects both 3D and FEM. **Dia. Chord- Top Horz. Dist. of WP from Center of Girder:** Horizontal distance between the diagonal chord's top WP and the girder centerline. Affects both 3D and FEM. **Dia. Chord- Top Inner Offset from WP:** Inner offset of the diagonal chord's top working point. Affects both 3D and FEM. **Dia. Chord- Bot. Vert. Dist. of WP from Bottom of Girder:** Vertical distance between the diagonal chord's bottom WP and the bottom of the precast girder. Affects both 3D and FEM. **Dia. Chord- Bot. Horz. Dist. of WP from Center of Girder:** Horizontal distance between the diagonal chord's bottom WP and the girder centerline. Affects both 3D and FEM. **Dia. Chord- Bot. Inner Offset from WP:** Inner offset of the diagonal chord's bottom working point. Affects both 3D and FEM. **Bot. Chord- Vert. Dist. of WP from Bottom of Girder:** Vertical distance between the WP of the bottom chord and the bottom of the girder. Affects both 3D and FEM. **Bot. Chord- Horz. Dist. of WP from Center of Girder:** Horizontal distance between the WP of the bottom chord and the girder centerline. Affects both 3D and FEM. **Bot. Chord- Inner Offset from WP:** Inner offset of the bottom chord's working point. Affects both 3D and FEM. ## Gusset Plate The parameters listed below are used for 3D representation only. Gusset plates do not contribute stiffness to the FEM but their weight is included in quantity takeoffs and code checks when configured. **Top Gusset Plate:** Assign a Gusset Plate defined under Superstructure > Connections. **Bottom Gusset Plate:** Assign a Gusset Plate defined under Superstructure > Connections. **Center Gusset Plate:** Assign a Gusset Plate at the crossing point of the diagonals. Available when **Has Middle Gusset Plate?** is YES. **Top Plate - Vert. Offset from Top of Girder:** Vertical offset of the top gusset plate from the top of the precast girder. **Top Plate - Horz. Offset from Edge of Girder:** Horizontal offset of the top gusset plate from the edge of the precast girder. **Bottom Plate - Vert. Offset from Bottom of Girder:** Vertical offset of the bottom gusset plate from the bottom of the precast girder. **Bottom Plate - Horz. Offset from Edge of Girder:** Horizontal offset of the bottom gusset plate from the edge of the precast girder. **Center Plate - Vert. Offset from Cross Frame Center:** Vertical offset of the center gusset plate from the center of the cross frame. **Center Plate - Horz. Offset from Center of Bay:** Horizontal location of the center gusset plate relative to the midpoint between the two girders (the bay). Positive values offset to the right, negative to the left when looking upstation along the PGL. **Show Gusset Plate \[YES/NO]:** Controls whether gusset plates are displayed in the 3D view. ## Stiffener Parameters for 3D representation of the cross-frame stiffener plate. Stiffeners do not contribute stiffness to the FEM by default but can be included as weight loads. **Stiffener Used \[YES/NO]:** When YES, the stiffener sub-parameters become editable; when NO, they are not applicable. **Vertical Stiffener Thickness:** Thickness of the vertical stiffener plate. **Vertical Stiffener Width:** Width of the vertical stiffener plate. **Distance from Top of Girder:** Clear distance between the top of the stiffener plate and the top of the precast girder. **Distance from Bottom of Girder:** Clear distance between the bottom of the stiffener plate and the bottom of the precast girder. **Vertical Clip Height:** Vertical dimension of the corner clip trimmed from the stiffener. **Horizontal Clip Width:** Horizontal dimension of the corner clip trimmed from the stiffener. **Material:** Material assigned to the stiffener plate. Import or pick a previously defined material. **Show Stiffener \[YES/NO]:** Controls whether the stiffener is rendered in the 3D view. **Generate FEM \[YES/NO]:** When NO, the cross-frame's analytical members are not generated. ## FEA For detailed explanations on axial rigidity coefficients, refer to the AASHTO excerpts below. **Top Chord Axial Rigidity Coefficient:** Multiplier applied to the axial rigidity (EA) of the top chord in the FEM. **Bottom Chord Axial Rigidity Coefficient:** Multiplier applied to the axial rigidity (EA) of the bottom chord in the FEM. **Diagonal Chord Axial Rigidity Coefficient:** Multiplier applied to the axial rigidity (EA) of the diagonal chord in the FEM. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.openbrim.org/templates/precast-i-girder-bridge-workflow/superstructure-pig/bracing-pig/cross-frame-x-pig.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.