An IfcBeam is a horizontal, or nearly horizontal, structural member that is capable of withstanding load primarily by resisting bending. It represents such a member from an architectural point of view. It is not required to be load bearing.
NOTE Definition according to ISO 6707-1:
structural member for carrying load(s) between or beyond points of support, usually narrow in relation to its length and horizontal or nearly so.
NOTE The representation of load-bearing beams in a structural analysis model is provided by subtypes of IfcStructuralMember (with IfcStructuralCurveMember being mostly applicable) as part of an IfcStructuralAnalysisModel.
NOTE For any other longitudinal structural member, not constrained to be predominately horizontal nor vertical, or where this semantic information is irrelevant, the entity IfcMember should be used.
There are two entities for beam occurrences:
- IfcBeamStandardCase used for all occurrences of beams, that have a profile defined that is swept along a directrix. The profile might be changed uniformly by a taper definition along the directrix. The profile parameter and its cardinal point of insertion can be fully described by the IfcMaterialProfileSetUsage. These beams are always represented geometricly by an 'Axis' and a 'SweptSolid' or 'AdvancedSweptSolid' shape representation (or by a 'Clipping' geometry based on the swept solid), if a 3D geometric representation is assigned. In addition they have to have a corresponding IfcMaterialProfileSetUsage assigned.
NOTE Model view definitions and implementer agreements may further constrain the applicable geometry types, for example, by excluding tapering from an IfcBeamStandardCase implementation.
- IfcBeam used for all other occurrences of beams, particularly for beams with changing profile sizes along the extrusion, or beams defined by non-linear extrusion, or beams having only 'Brep', or 'SurfaceModel' geometry.
NOTE Model view definitions and implementer agreements may impose the use of IfcBeam in all cases by excluding IfcBeamStandardCase from scope of the model view.
HISTORY New entity in IFC1.0
Common Use Definitions
The following concepts are inherited at supertypes:
- IfcRoot: Identity, Revision Control
- IfcElement: Product Placement, Box Geometry, FootPrint Geometry, Body SurfaceOrSolidModel Geometry, Body SurfaceModel Geometry, Body Tessellation Geometry, Body Brep Geometry, Body AdvancedBrep Geometry, Body CSG Geometry, Mapped Geometry
- IfcBuildingElement: Surface 3D Geometry
The Object Typing concept applies to this entity as shown in Table 80.
Table 80 — IfcBeam Object Typing
Property Sets for Objects
The Property Sets for Objects concept applies to this entity as shown in Table 81.
Table 81 — IfcBeam Property Sets for Objects
The Quantity Sets concept applies to this entity as shown in Table 82.
Table 82 — IfcBeam Quantity Sets
The Spatial Containment concept applies to this entity as shown in Table 83.
|IfcBuildingStorey||Default spatial container |
|IfcBuilding||Spatial container for the element if it cannot be assigned to a building storey|
|IfcSite||Spatial container for the element in case that it is placed on site (outside of building) |
Table 83 — IfcBeam Spatial Containment
The IfcBeam, as any subtype of IfcBuildingElement,
may participate alternatively in one of the two different containment relationships:
- the Spatial Containment (defined here), or
- the Element Composition.
The Element Composition concept applies to this entity as shown in Table 84.
Table 84 — IfcBeam Element Composition
Material Profile Set
The Material Profile Set concept applies to this entity.
The material of the IfcBeam is defined by the
IfcMaterialProfileSet or as fallback by IfcMaterial, and it is attached either directly or at the IfcBeamType.
NOTE It is illegal to assign an IfcMaterialProfileSetUsage to an IfcBeam. Only the subtype IfcBeamStandardCase supports this
Axis 3D Geometry
The Axis 3D Geometry concept applies to this entity as shown in Table 85.
|Axis||Curve3D||IfcBoundedCurve||Three-dimensional reference curve for the beam.|
Table 85 — IfcBeam Axis 3D Geometry
The 'Axis' 'Curve 3D' geometry can be used to represent the system
axis and length of a beam that may extent the body
NOTE The 'Axis' is not used to locate the
material profile set, only the subtype IfcBeamStandardCase
provides this capability.
Body SweptSolid Geometry
The Body SweptSolid Geometry concept applies to this entity.
The following additional constraints apply to the 'SweptSolid' representation type:
Figure 161 illustrates the 'SweptSolid' geometric representation. There are no restrictions or conventions on how to use the local placement (black), solid of extrusion placement (red) and profile placement (green).
Figure 161 — Beam swept solid
Figure 162 illustrates the use of non-perpendicular extrusion to create the IfcExtrudedAreaSolid.
Figure 162 — Beam non-perpendicular extrusion
Body AdvancedSweptSolid Geometry
The Body AdvancedSweptSolid Geometry concept applies to this entity.
The following additional constraints apply to the 'AdvancedSweptSolid' representation type:
Body Clipping Geometry
The Body Clipping Geometry concept applies to this entity.
The following additional constraints apply to the 'Clipping' representation type:
- Solid: see 'SweptSolid' geometric representation
- Profile: see 'SweptSolid' geometric representation
- Extrusion: see 'SweptSolid' geometric representation
- Boolean result: The IfcBooleanClippingResult
shall be supported, allowing for Boolean differences between the
swept solid (here IfcExtrudedAreaSolid) and one or several
IfcHalfSpaceSolid (or its subtypes).
Figure 163 illustrates use of IfcBooleanClippingResult between an IfcExtrudedAreaSolid and an IfcHalfSpaceSolid to create a clipped body.
Figure 163 — Beam clipping
The Product Assignment concept applies to this entity as shown in Table 86.
Table 86 — IfcBeam Product Assignment
XSD Specification: <xs:element name="IfcBeam" type="ifc:IfcBeam" substitutionGroup="ifc:IfcBuildingElement" nillable="true"/>
<xs:attribute name="PredefinedType" type="ifc:IfcBeamTypeEnum" use="optional"/>
|CorrectPredefinedType|| : ||NOT(EXISTS(PredefinedType)) OR
(PredefinedType <> IfcBeamTypeEnum.USERDEFINED) OR
((PredefinedType = IfcBeamTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));|
|CorrectTypeAssigned|| : ||(SIZEOF(IsTypedBy) = 0) OR
('IFCSHAREDBLDGELEMENTS.IFCBEAMTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy.RelatingType));|
|PredefinedType|| : ||
Predefined generic type for a beam that is specified in an enumeration. There may be a property set given specificly for the predefined types.
NOTE The PredefinedType shall only be used, if no IfcBeamType is assigned, providing its own IfcBeamType.PredefinedType.
IFC4 CHANGE The attribute has been added at the end of the entity definition.
|CorrectPredefinedType|| : ||
Either the PredefinedType attribute is unset (e.g. because an IfcBeamType is associated), or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.
|CorrectTypeAssigned|| : ||
Either there is no beam type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcBeamType.
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