# Cantilever Abutment \[CUG] The Cantilever Abutment object supports both 3D visualization and optional finite element modeling. By default, the Generate FEM option is set to 'NO', but when enabled, the abutment can be discretized into shell elements for structural analysis. Abutments can be modeled in 3D and 2D with parametric dependencies to closely represent the actual conditions of the bridge. ## General **Location:** The location of the abutments can be determined by the chosen support lines. **Front/Back \[Front/Back]:** Defines the directional placement of the abutment along the PGL, ensuring it aligns correctly with the overall bridge structure. Select 'Front' for a forward-facing abutment (front of bridge start) and 'Back' for the opposite orientation. ![Front and Back Abutment Orientation.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Ads%C4%B1z%20tasar%C4%B1m%20\(6\).png?api=v2) **Transverse Offset:** The transverse offset value can be specified to further define the bridge location. The transverse offset refers to the offset measured along the support line. Hidden when Use Custom Alignments for Abutment Edges is enabled — the offset is then derived from the projected edge alignments. {% hint style="info" %} When working with a support line that has a skew angle greater than 0 in OpenBrIM, it is important for users to specify the transverse offset(T) along the support line, not along the PGL(Y). {% endhint %} ![Transverse Offset Along Skewed Support Line.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Ads%C4%B1z%20tasar%C4%B1m%20\(14\).png?api=v2) {% hint style="info" %} The positive direction of the Y-axis will be to the left when looking upstream along the PGL. However, based on the requests of engineers who have been using OpenBrIM for their bridge projects, positive transverse offset values will indicate the right-hand side when looking upstream along the PGL. This distinction should be taken into account when defining the location of bridge elements using transverse offset values (where positive transverse offset indicates the right side), as well as when making definitions related to FEM and loading (where positive Fy indicates the left side along the PGL). {% endhint %} **Longitudinal Offset:** The longitudinal offset value can be specified to offset the abutment with respect to the longitudinal (along PGL) direction. A negative value would mean offsetting the abutment in the downstation direction, while a positive value would mean offsetting the abutment in the upstation direction. ![Longitudinal Offset Direction.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Ads%C4%B1z%20tasar%C4%B1m%20\(12\).png?api=v2) **Material:** Assign a material to the abutment. Materials can be selected from previously defined options or imported as needed. **Use Custom Alignments for Abutment Edges \[No/Yes]:** When set to 'Yes', the abutment width, transverse offset, front-wall plane rotations, back-wall geometry, and wing-wall transverse offsets / start-face skews / rotation angles are computed from two user-supplied alignments instead of from the numeric parameter inputs. The alignments are projected onto the seat back line; their intersections become the left and right edges of the abutment. Use this when the abutment edges must follow specific alignments (for example, the edges of an over-crossing roadway) rather than a constant width about the support line. While the toggle is enabled, the parameters that would otherwise drive these dimensions (Transverse Offset, Width, Geometry Source, Left/Right Plane Rotation, wing-wall Transverse Offset, Angle of Start Face Plane, and Rotation Angle) are hidden. **Alignment (Left Edge of Abutment):** The alignment that defines the left edge of the abutment when Use Custom Alignments for Abutment Edges is enabled. The intersection of this alignment with the seat back line determines the left abutment edge point. Required when the toggle is enabled. **Alignment (Right Edge of Abutment):** The alignment that defines the right edge of the abutment when Use Custom Alignments for Abutment Edges is enabled. The intersection of this alignment with the seat back line determines the right abutment edge point. Required when the toggle is enabled. ## **Seat** **Geometry Source \[Parameters/Section]:** This parameter specifies how the seat geometry is defined. When 'Parameters' is selected, the seat is defined using width and length parameters. When 'Section' is selected, the seat uses a predefined section profile. Hidden when Use Custom Alignments for Abutment Edges is enabled (the seat is then forced to the parameter-driven width derived from the edge alignments). **Section:** The section of the seat can be specified. ![Seat Section Reference.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Ads%C4%B1z%20tasar%C4%B1m%20\(16\).png?api=v2) {% hint style="info" %} For abutment sections, the left–right reference is defined by standing behind the abutment and looking forward in the direction of the bridge axis. {% endhint %} * **Width:** The width of seat/back-wall can be specified using this parameter along the transverse direction (perpendicular to PGL). For a visual representation, refer to the screenshots below. * **Depth:** The elevation of the bottom of the modeled abutment can be specified using this depth parameter of section. The elevation data should be defined with respect to the Global Coordinate System, where 0 represents the level of PGL (the vertical elevation data considered). The depth parameter is referenced starting from the PGL. ![Seat Section Width and Depth.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(6\).png?api=v2) ![Seat Depth Reference from PGL.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(5\).png?api=v2) **Width:** The width of the seat/back-wall can be specified using this parameter along the transverse direction (perpendicular to PGL). For the visual presentation, refer to the width value in the section title.(The seat/back-wall width input can be used only when the seat/back-wall section is null). Hidden when Use Custom Alignments for Abutment Edges is enabled — the width is derived from the distance between the projected edge alignments. **Length:** The Length of the seat/back-wall in the longitudinal direction can be specified using this parameter. For a visual representation, refer to the screenshots below. ![Seat Length Along Longitudinal Direction.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(8\).png?api=v2) **Override Top Elevation:** This is used to override the upper portion of the seat/back-wall section. When defined, it allows you to enter a top-elevation value. **Seat Top Elevation:** When the seat top elevation override is enabled, defines the top-of-seat profile as a table of segments. Each row specifies a transverse length, elevation, geometry option (Flat/Sloped) and second elevation for the sloped case. Rows are evaluated starting from the right when looking upstation along the PGL. * **Length**: Starting from the right when looking upstation along the PGL, the length in the transverse direction for the top elevation can be defined by this parameter to further specify its variation. * **Elevation**: This parameter represents the initial elevation of the seat/back-wall based on the defined length. * **Geometry Option \[Flat/Sloped]**: The elevation can either remain constant throughout the defined length or vary as a slope. * **Elevation 1**: For sloped sections, a second elevation value can be defined for the initial point of the specified length. ![Seat Top Elevation Profile.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(10\).png?api=v2) ![image-20251114-100329.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/image-20251114-100329.png?api=v2) ![Seat Top Elevation Segments.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(15\).png?api=v2) {% hint style="info" %} For abutment sections, the left–right reference is defined by standing behind the abutment and looking forward in the direction of the bridge axis. {% endhint %} **Override Bottom Elevation:** This is used to override the bottom portion of the seat/back-wall section. When defined, it allows you to specify a bottom-elevation value. **Seat Bottom Elevation:** When the seat bottom elevation override is enabled, defines the bottom-of-seat profile as a table of segments. Each row specifies a transverse length, elevation, geometry option (Flat/Sloped) and second elevation for the sloped case. Rows are evaluated starting from the right when looking upstation along the PGL. * **Length**: Starting from the right when looking upstation along the PGL, the length in the transverse direction for the bottom elevation can be defined by this parameter to further specify its variation. * **Elevation**: This parameter represents the initial elevation of the seat/back-wall based on the defined length. * **Geometry Option \[Flat/Sloped]**: The elevation can either remain constant throughout the defined length or vary as a slope. * **Elevation 1**: For sloped sections, a second elevation value can be defined for the initial point of the specified length. ![Seat Bottom Elevation Profile.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(12\).png?api=v2) ![image-20251114-102906.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/image-20251114-102906.png?api=v2) **Left Plane Rotation:** Specifies the rotation angle of the left face plane of the seat. This controls the angular orientation of the left edge of the abutment seat, allowing it to be adjusted to match non-standard geometry or skewed configurations. Hidden when Use Custom Alignments for Abutment Edges is enabled — the left plane rotation is set automatically from the left edge alignment's projection angle. **Right Plane Rotation:** Specifies the rotation angle of the right face plane of the seat. This controls the angular orientation of the right edge of the abutment seat. Hidden when Use Custom Alignments for Abutment Edges is enabled — the right plane rotation is set automatically from the right edge alignment's projection angle. ## **Back Wall** **Geometry Source \[Parameters/Section]:** This parameter specifies how the back wall geometry is defined. When 'Parameters' is selected, the back wall is defined using width and length parameters. When 'Section' is selected, the back wall uses a predefined section profile. Hidden when Use Custom Alignments for Abutment Edges is enabled (the back wall is then forced to the parameter-driven width derived from the edge alignments). **Section:** The section of the back wall can be specified. **Width (Perpendicular to pgl):** The width of the back wall in the transverse direction (perpendicular to PGL). Hidden when Use Custom Alignments for Abutment Edges is enabled — the back wall width follows the distance between the projected edge alignments. **Length:** The length of the back wall in the longitudinal direction. **Back Wall Longitudinal Offset:** The longitudinal offset of the back wall relative to the seat. This allows the back wall to be shifted in the along-PGL direction independently of the overall abutment longitudinal offset. A positive value moves the back wall in the upstation direction, while a negative value moves it downstation. This is useful when the back wall needs to be positioned at a different longitudinal location than the seat centerline. **Back Wall Top Elevation:** When the back wall top elevation override is enabled, defines the top-of-back-wall profile as a table of segments (Length, Elevation, Geometry Option \[Flat/Sloped], second Elevation for sloped). Rows are evaluated starting from the right when looking upstation along the PGL. **Back Wall Bottom Elevation:** When the back wall bottom elevation override is enabled, defines the bottom-of-back-wall profile as a table of segments (Length, Elevation, Geometry Option \[Flat/Sloped], second Elevation for sloped). Rows are evaluated starting from the right when looking upstation along the PGL. ## **Right/Left Wing Wall** **Wing Wall\[YES/NO]:** This parameter indicates whether it will be a wing wall.\ **Section:** The section of the wing wall can be specified. ![image-20251117-105914.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/image-20251117-105914.png?api=v2) {% hint style="info" %} For abutment sections, the left–right reference is defined by standing behind the abutment and looking forward in the direction of the bridge axis. {% endhint %} * **Top Slope Option\[Slope/From Alignment]:** This defines the option for the wing wall’s top slope. If ‘**Slope**’ is selected, the value can be entered manually. If ‘**From Alignment**’ is selected, the slope is taken from the alignment. * **Depth:** This specifies the depth of the wing wall on the abutment side.![Wing Wall Top Slope and Depth.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(16\).png?api=v2) **Wall Length:** The length of the wing wall in the longitudinal direction (along PGL). Used when the wing wall geometry is derived from parameters rather than a section profile. ![Wing Wall Length Along PGL.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(17\).png?api=v2) **Longitudinal Offset:** The longitudinal offset value specifies the wing wall's position relative to the longitudinal (along PGL) direction. A negative value offsets the wing wall in the downstation direction, while a positive value offsets it in the upstation direction. ![Wing Wall Longitudinal Offset.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(18\).png?api=v2) **Transverse Offset:** This offsets the Wing Wall in the direction of the backwall. Hidden when Use Custom Alignments for Abutment Edges is enabled — the wing-wall transverse offset is positioned to match the corresponding abutment edge alignment. ![Wing Wall Transverse Offset.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(19\).png?api=v2) **Angle of Start Face Plane:** This specifies the plane angle to the geometry of the wing wall’s start points. Hidden when Use Custom Alignments for Abutment Edges is enabled — the start-face plane is rotated automatically to align with the projected edge alignment. **Angle of End Face Plane:** This specifies the plane angle to the geometry of the wing wall’s end points. ![Wing Wall Start and End Face Plane Angles.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(32\).png?api=v2) **Angle:** This specifies the angle based on the point where it intersects the abutment. ![Wing Wall Angle at Abutment Intersection.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(33\).png?api=v2) **Rotation Angle:** This parameter specifies the rotation angle of the wing wall around its longitudinal axis. Hidden when Use Custom Alignments for Abutment Edges is enabled — the rotation angle is computed from the angle between the support line and the corresponding edge alignment. **Adjust Bottom Elevation with Bottom Elevation of Backwall \[YES/NO]:** This matches the bottom elevation of wing wall with the bottom elevation of the backwall. **Override Bottom Elevation \[YES/NO]:** When enabled, allows you to manually specify the bottom elevation of the wing wall instead of using the automatically calculated value. This is useful when the wing wall needs to extend to a specific elevation that differs from the default. **Bottom Elevation:** The bottom elevation of the wing wall. When "Override Bottom Elevation" is set to YES, this value can be entered manually. Otherwise, it is displayed as read-only and computed automatically. **Top Vertical Offset:** Specifies a vertical offset applied to the top of the wing wall. This allows fine-tuning of the wing wall's top elevation relative to the default position derived from the alignment or slope settings. ![Wing Wall Top Vertical Offset.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(23\).png?api=v2) ## **3D Visualization** **Right Chamfer \[No/Yes]:** Indicates whether a chamfer is created on the right side of the abutment (right when looking upstation along the PGL). **Right Chamfer Width:** The chamfer width in the direction of the abutment. **Right Chamfer Length:** The chamfer length in the direction of the wing wall. ![Right Chamfer Width and Length.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(24\).png?api=v2) **Right Chamfer Bottom Option \[Depth/Elevation]:** Controls how the right chamfer's lower extent is defined. Choose 'Depth' to measure downward from the top of the wing wall, or 'Elevation' to specify an absolute bottom elevation. **Right Chamfer Bottom Elevation:** When Right Chamfer Bottom Option is 'Elevation', specifies the absolute bottom elevation of the right chamfer. Use this when the chamfer must terminate at a specific elevation rather than a fixed depth below the wing wall top. **Right Chamfer Depth:** When Right Chamfer Bottom Option is 'Depth', the vertical depth of the right chamfer measured downward from the top of the wing wall. **Right Chamfer Vertical Offset:** Vertical offset from the top of the wing wall to the top of the right chamfer. Use this to start the chamfer a specific distance below the wing wall top. **Right Chamfer Transverse Offset:** The transverse offset of the right chamfer from the wing wall. **Left Chamfer \[No/Yes]:** Indicates whether a chamfer is created on the left side of the abutment. **Left Chamfer Width:** The chamfer width in the direction of the abutment. **Left Chamfer Length:** The chamfer length in the direction of the wing wall. **Left Chamfer Bottom Option \[Depth/Elevation]:** Controls how the left chamfer's lower extent is defined. Choose 'Depth' to measure downward from the top of the wing wall, or 'Elevation' to specify an absolute bottom elevation. **Left Chamfer Bottom Elevation:** When Left Chamfer Bottom Option is 'Elevation', specifies the absolute bottom elevation of the left chamfer. **Left Chamfer Depth:** When Left Chamfer Bottom Option is 'Depth', the vertical depth of the left chamfer measured downward from the top of the wing wall. **Left Chamfer Vertical Offset:** Vertical offset from the top of the wing wall to the top of the left chamfer. **Left Chamfer Transverse Offset:** The transverse offset of the left chamfer from the wing wall. ![Left Chamfer Dimensions.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(25\).png?api=v2) ## **Finite Element Model (FEM)** **Generate FEM \[YES/NO]:** Controls whether a finite element model is generated for the abutment. When enabled, the abutment geometry is discretized into shell elements for structural analysis. The default is 'NO'. **Mesh Size:** Specifies the target element size for the finite element mesh of the abutment. Smaller values produce a finer mesh with more elements, yielding more accurate results but requiring greater computational resources. The value is specified in length units. **Mesh Algorithm:** Specifies the meshing algorithm used to generate the finite element mesh. Different algorithms may produce different mesh quality and element distributions depending on the abutment geometry. **Rigid Material:** Specifies the material used for rigid link elements in the finite element model. Rigid links are used to connect the abutment to bearings and other structural components. **Rigid Section:** Specifies the section used for rigid link elements in the finite element model. **Override Right Wing Wall Thickness \[No/Yes]:** When enabled, allows the right wing wall thickness in the finite element model to be specified manually instead of using the value derived from the wing wall section geometry. **Right Wing Wall Thickness:** When the override is enabled, specifies the thickness value to use for the right wing wall in the finite element model. **Override Left Wing Wall Thickness \[No/Yes]:** When enabled, allows the left wing wall thickness in the finite element model to be specified manually instead of using the value derived from the wing wall section geometry. **Left Wing Wall Thickness:** When the override is enabled, specifies the thickness value to use for the left wing wall in the finite element model. ## **Quantities** **Total Top Face Area :** ![Total Top Face Area.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(27\).png?api=v2) **Total Bottom Face Area:** ![Total Bottom Face Area.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(29\).png?api=v2) **Total Surface Area:** All visible areas of the object shown in the visual representation below (In the visual representation below, the seat and back wall are treated as a single solid for the area calculation). ![Total Surface Area.png](https://openbrim.atlassian.net/wiki/download/attachments/3429695489/Paragraf%20metniniz%20\(31\).png?api=v2) ### Wing Wall Quantities **Max Height Left Wing Wall:** The maximum height of the left wing wall. **Min Height Left Wing Wall:** The minimum height of the left wing wall. **Length Left Wing Wall:** The length of the left wing wall. **Thickness Left Wing Wall:** The thickness of the left wing wall. **Max Height Right Wing Wall:** The maximum height of the right wing wall. **Min Height Right Wing Wall:** The minimum height of the right wing wall. **Length Right Wing Wall:** The length of the right wing wall. **Thickness Right Wing Wall:** The thickness of the right wing wall. ### Seat Quantities **Seat Max Depth:** The maximum depth of the seat. **Seat Min Depth:** The minimum depth of the seat. **Seat Thickness:** The thickness of the seat. **Seat Width:** The transverse width of the seat (perpendicular to the PGL). (Read-only) ### Back Wall Quantities **Back Wall Max Depth:** The maximum depth of the back wall. **Back Wall Min Depth:** The minimum depth of the back wall. **Back Wall Thickness:** The thickness of the back wall. **Back Wall Width:** The transverse width of the back wall (perpendicular to the PGL). (Read-only) ### General Quantities **Volume:** The total volume of the abutment. **Filled Bottom Area Volume:** The volume of the filled area at the bottom of the abutment used when the seat bottom profile extends below the default footprint (e.g. for stepped or tapered bases). (Read-only) **Rebar Density(per cubic foot):** The rebar density used for calculating the rebar weight of the abutment. Enter the expected weight of reinforcement per unit volume (force per cubic length in the active unit system). **Rebar Weight:** The calculated rebar weight based on the rebar density and abutment volume. (Read-only) **Weight:** The total weight of the abutment. (Read-only) **Material (Read-Only):** Displays the assigned material for the abutment. --- # 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/concrete-u-girder-bridge-workflow/substructure-cug/abutment-system-cug/cantilever-abutment-cug.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.