> For the complete documentation index, see [llms.txt](https://docs.openbrim.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.openbrim.org/templates/truss-bridge-workflow/substructure-tb/pier-tb/flared-wall-pier-tb.md). # Flared Wall Pier \[TB] A flared wall pier is a concrete wall pier whose cap, legs and stem are one body: a cap that flares out at one or both ends, two legs that curve down into a vertical stem, and a through opening between the legs. The pier stands on a support line, in the plane of the support line, so it follows the skew of the support line. One outline in the plane of the pier drives the 3D model, the finite element model and the quantities. ![A flared wall pier with both cap ends flared (the default)](https://2645910244-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGR3Y2oTOZjlXFJKoQ7ar%2Fuploads%2Fgit-blob-18e45f957e149551904030302df38fe36b852c02%2Fflared-wall-pier-3d.png?alt=media) {% hint style="info" %} **How the outline is built** The outline is described in an elevation looking up-station, so the left end of the pier is on the left. Its heights are measured from the bottom of the pier. * **Flared end.** The tip lies **Tip Projection** outside and **Tip Drop** below the end of the cap top. Below the tip, a straight face of the given height runs down at the given angle from horizontal. At its foot (the P.T.) the face is tangent to the leg arc. * **Square end.** A vertical end face of the given depth. Its foot lies on the leg arc. * **Leg arc.** Each leg is a circular arc of the **Leg Radius** that becomes vertical at its lowest point, the P.C. Below the P.C. the stem is vertical. Both legs have the same radius and the stem is centered on the pier CL, so the stem width follows from the **Cap Top Length** and the end geometry. A square end takes its P.C. height from the flared end, so at least one end must be flared. * **Built from the top down.** The flared end fixes the P.C.: its height above the bottom is the pier height less the tip drop, the straight face height and the vertical drop of the arc from the P.T. to the P.C. A shorter pier (a lower top or a higher bottom) with the same cap and legs therefore moves the P.C. down, and when it falls below the bottom of the pier, **Leg Radius** reports an issue. Reduce the leg radius, the straight face height or the tip drop, or make the pier taller. * **Opening.** Two corner marks at the **Opening Width at Corners**, at the **Opening Corner to Vertex Height** above the vertex. The vertex is on the pier CL, at the **Opening Vertex Height above Bottom**. A top arc of the **Opening Top Radius** passes through both corner marks, and straight sides run from the corner marks toward the vertex, with fillets of the **Opening Corner Radius** at the upper corners. The sides stop where the opening is **Opening Bottom Width** wide, and a bottom arc of the **Opening Bottom Radius** through the two stop points closes the opening. * **Chamfer.** Both faces of the wall are chamfered along the legs and around the opening. On the end faces the chamfer grows from zero at the cap top corner to the full chamfer at the foot of the end face. The cap top and the bottom edge are not chamfered. {% endhint %} The figures below show a pier with a square left end and a flared right end. ![Cap and legs: cap top length, the flared right end (tip projection, tip drop, straight face height and angle), the square left end (end face depth), the leg radius and its P.C., the chamfer and the stem width](https://2645910244-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGR3Y2oTOZjlXFJKoQ7ar%2Fuploads%2Fgit-blob-1ca947ca51bf366af943f3c734e2fdec6d3b0212%2Fflared-wall-pier-cap-and-legs.png?alt=media) ![The opening: width at the corners, corner to vertex height, vertex height above the bottom, the top, corner and bottom radii, the bottom width, the cap depth at the crown and the low point of the opening](https://2645910244-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGR3Y2oTOZjlXFJKoQ7ar%2Fuploads%2Fgit-blob-f0103ceeb94d60759eff00f2f6ff07639a4264f4%2Fflared-wall-pier-opening.png?alt=media) {% hint style="info" %} **Finite element model** * **Frame** (the default): the stem, the two legs and the cap are frame elements on their center lines, each element with the section of the outline at that point. Rigid elements connect them at the crotch and at the knees. * **Shell:** shell elements of the wall thickness in the mid-plane of the wall. The mesh is made of the two halves of the elevation on either side of the opening center line, which share their nodes on that line. * Each bearing on the support line that lies over the cap, with **Transfer Forces to Substructure** set to Yes, is connected from the top of the cap to the bearing with a rigid spring. * The bottom of the pier is fixed, or tied to the footing with rigid elements when a footing with a finite element model picks this pier. {% endhint %} ## General **Support Line:** The support line the pier stands on. The pier is placed in the plane of the support line and follows its skew. A value is required. **Material:** Concrete material of the pier. It is used in the 3D model, the finite element model and the quantities. A value is required. **Transverse Offset:** Offset of the pier CL from the support line location, measured along the support line. Positive values place the pier to the right when looking up-station. **Longitudinal Offset:** Offset of the mid-plane of the wall from the support line, measured perpendicular to the support line. Positive values move the pier ahead station. **Top Elevation Mode \[Offset from Alignment/Elevation]:** Selects how the top of the pier is positioned. **Offset from Alignment** places the cap top at a depth below the alignment surface at the pier CL; **Elevation** sets a global elevation directly. **Top Elevation Offset from Alignment:** Depth of the cap top below the alignment surface (the profile grade and the cross slope at the pier CL). Enter it as a positive value. Used when **Top Elevation Mode** is Offset from Alignment. The default is 6 ft. **Top Elevation:** Global elevation of the cap top. Used when **Top Elevation Mode** is Elevation. **Bottom Elevation:** Global elevation of the bottom of the pier. It must be below the top of the pier. **Wall Thickness:** Thickness of the wall, perpendicular to the plane of the pier. **Chamfer:** Size of the chamfer on both faces of the wall. Enter 0 for no chamfer. It must be less than half the wall thickness. **Height (readonly):** Height of the pier, from its bottom to the cap top (Read-only). ## Cap and Legs **Cap Top Length:** Length of the flat cap top, from its left end to its right end, without the flared tips. With the leg radius and the end geometry it sets the stem width; the object reports an issue when the stem width comes out zero or less. **Leg Radius:** Radius of the arc of both legs, from the foot of the end faces down to the P.C., where the leg becomes vertical and turns into the stem. It must be greater than zero, and the P.C. must be above the bottom of the pier (see **How the outline is built** above). **Left End \[Square/Flared]:** Shape of the left end of the cap. **Flared** (the default) gives a tip outside the cap top and a straight face below it; **Square** gives a vertical end face. At least one end must be flared. **Left Tip Projection:** Horizontal distance from the left end of the cap top out to the tip of the flare. Only editable when **Left End** is Flared. **Left Tip Drop:** Vertical distance from the cap top down to the tip of the left flare. Only editable when **Left End** is Flared. **Left Straight Face Height:** Vertical height of the straight face below the tip, down to its foot (the P.T.), where it meets the leg arc. Only editable when **Left End** is Flared. **Left Straight Face Angle from Horizontal:** Angle of the straight face from horizontal, between 0 and 90 degrees. The default is 60 degrees. Only editable when **Left End** is Flared. **Left End Face Depth:** Depth of the vertical end face below the cap top. Its foot must lie above the P.C. Only editable when **Left End** is Square. **Right End \[Square/Flared]:** Shape of the right end of the cap, as for the left end. The default is **Flared**. **Right Tip Projection:** Horizontal distance from the right end of the cap top out to the tip of the flare. Only editable when **Right End** is Flared. **Right Tip Drop:** Vertical distance from the cap top down to the tip of the right flare. Only editable when **Right End** is Flared. **Right Straight Face Height:** Vertical height of the straight face below the tip, down to its foot (the P.T.), where it meets the leg arc. Only editable when **Right End** is Flared. **Right Straight Face Angle from Horizontal:** Angle of the straight face from horizontal, between 0 and 90 degrees. The default is 60 degrees. Only editable when **Right End** is Flared. **Right End Face Depth:** Depth of the vertical end face below the cap top. Its foot must lie above the P.C. Only editable when **Right End** is Square. **Stem Width (readonly):** Width of the vertical stem below the P.C., centered on the pier CL (Read-only). **Cap Top Left End from Pier CL (readonly):** Distance from the pier CL to the left end of the cap top (Read-only). **Cap Top Right End from Pier CL (readonly):** Distance from the pier CL to the right end of the cap top (Read-only). **Leg Arc P.C. Height above Bottom (readonly):** Height of the P.C. above the bottom of the pier, taken from the flared end (the right end when both ends are flared) (Read-only). ## Opening **Opening Width at Corners:** Width between the two corner marks of the opening, where the top arc meets the straight sides. It must be greater than the opening bottom width, and the opening must lie between the bottom of the pier and the cap top. **Opening Top Radius:** Radius of the arc that forms the top of the opening, through both corner marks. It must be greater than half the opening width. **Opening Corner Radius:** Radius of the fillets at the two upper corners of the opening. It must be greater than zero. **Opening Corner to Vertex Height:** Vertical distance from the corner marks down to the vertex, the point on the pier CL toward which the straight sides run. **Opening Vertex Height above Bottom:** Height of the vertex above the bottom of the pier. **Opening Bottom Width:** Width of the opening where the straight sides stop, near the vertex. It must be greater than zero. **Opening Bottom Radius:** Radius of the arc that closes the bottom of the opening, through the two points where the sides stop. It must be greater than half the opening bottom width. **Cap Depth at Opening Crown (readonly):** Depth of the cap on the pier CL, from the cap top down to the top of the opening (Read-only). It follows from the height of the pier and the opening inputs: change the **Opening Vertex Height above Bottom**, the **Opening Corner to Vertex Height** or the **Opening Top Radius** to change it. **Opening Low Point above Bottom (readonly):** Height of the lowest point of the opening above the bottom of the pier (Read-only). ## FEA **Generate FEM \[No/Yes]:** Whether the pier is included in the finite element model. **FE Model \[Frame/Shell]:** Type of the finite element model of the pier, **Frame** (the default) or **Shell** (see **Finite element model** above). Only editable when **Generate FEM** is Yes. **Mesh Size:** The maximum element size: the length of the frame elements along their center lines, or the size of the shell elements. Only editable when **Generate FEM** is Yes. ## 3D Detailing **Opacity:** Transparency of the 3D visualization. Range from 0 (fully transparent) to 1 (fully opaque). ## IFC **Type:** IFC entity type for export. The default is IfcColumn. **Predefined Type \[Column/Pierstem/Pierstem\_Segment/Pilaster/Standcolumn/Userdefined/Notdefined]:** IFC predefined type of the pier. The default is PIERSTEM. **Parent \[Bridge/Superstructure/Deck/Substructure/Foundation/Approach\_Structure/Retaining\_Structure]:** IFC parent container of the pier in the exported model hierarchy. The default is SUBSTRUCTURE. **Properties:** Additional IFC properties written to the exported pier, one row per property. ## Quantities **Volume:** Concrete volume of the pier, the outline over the wall thickness less the chamfers (Read-only). **Weight:** Weight of the pier, from its volume and the density of the material (Read-only). **Height:** Height of the pier, from its bottom to the cap top (Read-only). **Rebar Density(per cubic yard):** Assumed reinforcement weight per cubic yard of concrete, used for the rebar weight. The default is 300 lb per cubic yard. **Rebar Weight:** Reinforcement weight, the volume times the rebar density (Read-only). **Material:** Name of the material of the pier (Read-only). ## Referencing Objects **Foundations:** Footings that pick this pier (Read-only). When a footing with a finite element model picks the pier, the bottom of the pier is tied to the footing; otherwise it is fixed. **Pile:** Piles that pick this pier directly as their substructure (Read-only). Piles cannot stand on the pier itself: the pier reports an issue, and the footing under the pier must be picked as the piles' substructure instead. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. 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