IfcBeam

#	Attribute	Type	Cardinality	Description	B
9	PredefinedType	IfcBeamTypeEnum	[0:1]	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.	X

Rule	Description
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.

Inherited definitions from supertypes

Entity inheritance

Attribute inheritance

#	Attribute	Type	Cardinality	Description	B
IfcRoot
1	GlobalId	IfcGloballyUniqueId	[1:1]	Assignment of a globally unique identifier within the entire software world.	X
2	OwnerHistory	IfcOwnerHistory	[0:1]	Assignment of the information about the current ownership of that object, including owning actor, application, local identification and information captured about the recent changes of the object, NOTE only the last modification in stored - either as addition, deletion or modification.	X
3	Name	IfcLabel	[0:1]	Optional name for use by the participating software systems or users. For some subtypes of IfcRoot the insertion of the Name attribute may be required. This would be enforced by a where rule.	X
4	Description	IfcText	[0:1]	Optional description, provided for exchanging informative comments.	X
IfcObjectDefinition
	HasAssignments	IfcRelAssigns @RelatedObjects	S[0:?]	Reference to the relationship objects, that assign (by an association relationship) other subtypes of IfcObject to this object instance. Examples are the association to products, processes, controls, resources or groups.	X
	Nests	IfcRelNests @RelatedObjects	S[0:1]	References to the decomposition relationship being a nesting. It determines that this object definition is a part within an ordered whole/part decomposition relationship. An object occurrence or type can only be part of a single decomposition (to allow hierarchical strutures only).
	IsNestedBy	IfcRelNests @RelatingObject	S[0:?]	References to the decomposition relationship being a nesting. It determines that this object definition is the whole within an ordered whole/part decomposition relationship. An object or object type can be nested by several other objects (occurrences or types).	X
	HasContext	IfcRelDeclares @RelatedDefinitions	S[0:1]	References to the context providing context information such as project unit or representation context. It should only be asserted for the uppermost non-spatial object.
	IsDecomposedBy	IfcRelAggregates @RelatingObject	S[0:?]	References to the decomposition relationship being an aggregation. It determines that this object definition is whole within an unordered whole/part decomposition relationship. An object definitions can be aggregated by several other objects (occurrences or parts).	X
	Decomposes	IfcRelAggregates @RelatedObjects	S[0:1]	References to the decomposition relationship being an aggregation. It determines that this object definition is a part within an unordered whole/part decomposition relationship. An object definitions can only be part of a single decomposition (to allow hierarchical strutures only).	X
	HasAssociations	IfcRelAssociates @RelatedObjects	S[0:?]	Reference to the relationship objects, that associates external references or other resource definitions to the object.. Examples are the association to library, documentation or classification.	X
IfcObject
5	ObjectType	-		This attribute is out of scope for this model view definition and shall not be set.
	IsTypedBy	IfcRelDefinesByType @RelatedObjects	S[0:1]	Set of relationships to the object type that provides the type definitions for this object occurrence. The then associated IfcTypeObject, or its subtypes, contains the specific information (or type, or style), that is common to all instances of IfcObject, or its subtypes, referring to the same type.	X
	IsDefinedBy	IfcRelDefinesByProperties @RelatedObjects	S[0:?]	Set of relationships to property set definitions attached to this object. Those statically or dynamically defined properties contain alphanumeric information content that further defines the object.	X
IfcProduct
6	ObjectPlacement	IfcObjectPlacement	[0:1]	Placement of the product in space, the placement can either be absolute (relative to the world coordinate system), relative (relative to the object placement of another product), or constraint (e.g. relative to grid axes). It is determined by the various subtypes of IfcObjectPlacement, which includes the axis placement information to determine the transformation for the object coordinate system.	X
7	Representation	IfcProductRepresentation	[0:1]	Reference to the representations of the product, being either a representation (IfcProductRepresentation) or as a special case a shape representations (IfcProductDefinitionShape). The product definition shape provides for multiple geometric representations of the shape property of the object within the same object coordinate system, defined by the object placement.	X
	ReferencedBy	IfcRelAssignsToProduct @RelatingProduct	S[0:?]	Reference to the IfcRelAssignsToProduct relationship, by which other products, processes, controls, resources or actors (as subtypes of IfcObjectDefinition) can be related to this product.	X
IfcElement
8	Tag	IfcIdentifier	[0:1]	The tag (or label) identifier at the particular instance of a product, e.g. the serial number, or the position number. It is the identifier at the occurrence level.	X
	ConnectedTo	IfcRelConnectsElements @RelatingElement	S[0:?]	Reference to the element connection relationship. The relationship then refers to the other element to which this element is connected to.
	HasOpenings	IfcRelVoidsElement @RelatingBuildingElement	S[0:?]	Reference to the IfcRelVoidsElement relationship that creates an opening in an element. An element can incorporate zero-to-many openings. For each opening, that voids the element, a new relationship IfcRelVoidsElement is generated.	X
	ConnectedFrom	IfcRelConnectsElements @RelatedElement	S[0:?]	Reference to the element connection relationship. The relationship then refers to the other element that is connected to this element.	X
	ContainedInStructure	IfcRelContainedInSpatialStructure @RelatedElements	S[0:1]	Containment relationship to the spatial structure element, to which the element is primarily associated. This containment relationship has to be hierachical, i.e. an element may only be assigned directly to zero or one spatial structure.
	PositionedFrom	IfcRelPositions @RelatingElement	S[0:1]	Indicates a constrained placement, where the ObjectPosition must match positioning defined according to the referenced positioning element.	X
IfcBuildingElement
IfcBeam
9	PredefinedType	IfcBeamTypeEnum	[0:1]	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.	X

Definitions applying to Bridge View

Instance diagram

Girders are modelled as IfcBeam with IfcMaterialProfileSet indicating the material and cross-section. Steel girders are commonly represented as IfcAsymmetricIShapeProfileDef, while precast concrete girders may use custom cross-sections represented as IfcArbitraryClosedProfileDef.

Beam geometry may be generically described by applying the profile to an alignment curve using IfcFixedReferenceSweptAreaSolid. Alternatively, straight segments may use IfcExtrudedAreaSolid, and segments with tapered sections may use IfcExtrudedAreaSolidTapered. Alternatively, IfcSectionedSpine may be used to capture multiple discretized profile segments.

Figure 1 — Bridge girder model

As shown in Figure 1, girders may be split into segments according to defined splices. The gaps in the illustration are exagerated to show each segment.

Figure 2 — Bridge girder plans

The connection between beams is represented using IfcRelConnectsWithRealizingElements, where the RealizingElements refers to IfcPlate elements for fastening plates on each side, IfcFastener for bolts, and IfcPlate for any flange transition plates. The reason for using this connection relationship specifically (as opposed to just placing the elements) is to be able to derive an IfcStructuralAnalysisModel that captures the beam connectivity.

Geometry for bridge girders fits four general cases, where 'Alignment curves' indicates whether the horizontal and/or vertical alignment has any curvature (rather than straight line), 'Cross section rotates' indicates whether there is super-elevation such that the same profile may be rotated along the alignment, and 'Cross section varies' indicates that working points of the profile vary independently along the alignment, such as for keeping surfaces in contact with girders in the horizontal plane while the cross-section has an incline overall.

Entity	Alignment curves	Cross section rotates	Cross section varies
IfcExtrudedAreaSolid	No	No	No
IfcFixedReferenceSweptAreaSolid	Yes	No	No
IfcSurfaceCurveSweptAreaSolid	Yes	Yes	No
IfcSectionedSpine	Yes	Yes	Yes

Concept usage

Object Typing

The Object Typing concept applies to this entity as shown in Table 20.

Type
IfcBeamType

Table 20 — IfcBeam Object Typing

Exchange
Import		O
Export		O

Quantity Sets

The Quantity Sets concept applies to this entity as shown in Table 21.

Name
Qto_BeamBaseQuantities

Table 21 — IfcBeam Quantity Sets

Exchange
Import		O
Export		O

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 concept.

Exchange
Import		R
Export		R

Constraint Association

The Constraint Association concept applies to this entity.

For describing a connected series of beams along a single girder line, an IfcBeam may be used to describe the overall series and nested into component beams using IfcRelNests. As the profiles (e.g. flange width, flange thickness) and other dimensions may vary along the alignment, such parameters may be described within a table (IfcTable) applied as a constraint (IfcRelAssociatesConstraint) at the outer IfcBeam – such table usage then also provides the information in a form typically shown on plans.

As shown in Figure 2, the parameters may vary within different sections along girder spans. While the underlying geometry captures the values explicitly, the girder may be described parametrically with use of an IfcTable, shown below.

Figure 168 — Bridge girder table

Within the IfcTable shown in Figure 168, each column is represented by IfcTableColumn and may have mappings described as shown below.

Figure 169 — Bridge girder parameter

Such mappings are captured as a chain of IfcReference structures defined on IfcTableColumn.

Exchange
Import		O
Export		O

Structural Curve Assignment

The Structural Curve Assignment concept applies to this entity.

Camber ordinates may be derived from structural load results related to total dead load. For geometry that resides within spatial structures, it is assumed that all dimensions reflect the conditions as constructed in place (where such camber would be balanced out by resulting loads), therefore any camber must be modelled separately. To relate camber to specific load results and load cases, the IfcBeam may link to an idealized structural model using the assignment relationship IfcRelAssignsToProduct, where RelatedObjects refers to the IfcBeam and RelatedObjects contains one or more idealized IfcStructuralCurveMember instances, where load results may be traversed following the AssignedStructuralActivity inverse attribute where IfcRelConnectsStructuralActivity.AppliedLoad refers to an IfcStructuralCurveReaction instance within a result set (HasAssignments related to IfcStructuralResultGroup via IfcRelAssignsToGroup) corresponding to the load combination (IfcStructuralLoadGroup) and analytical member (IfcStructuralCurveMember).

Exchange
Import		R	R	R
Export		R	R	R

Axis 3D Geometry

The Axis 3D Geometry concept applies to this entity as shown in Table 22.

Identifier	Type	Items	Description
Axis	Curve3D	IfcBoundedCurve	Three-dimensional reference curve for the beam.

Table 22 — 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 length.

NOTE The 'Axis' is not used to locate the material profile set, only the subtype IfcBeamStandardCase provides this capability.

Exchange
Import
Export

Body SweptSolid Geometry

The Body SweptSolid Geometry concept applies to this entity as shown in Table 23.

Identifier

Type

Geometry

Body

SweptSolid

Swept Solid Geometry

Profile	Description
IfcArbitraryClosedProfileDef	Arbitrary solid profile
IfcArbitraryProfileDefWithVoids	Arbitrary hollow profile
IfcIShapeProfileDef	I-Shape with equal flange dimensions
IfcAsymmetricIShapeProfileDef	I-Shape with unequal flange dimensions

Table 23 — IfcBeam Body SweptSolid Geometry

The following additional constraints apply to the 'SweptSolid' representation type:

Solid: IfcExtrudedAreaSolid, IfcRevolvedAreaSolid shall be supported
Profile: all subtypes of IfcProfileDef (with exception of IfcArbitraryOpenProfileDef)
Extrusion: All extrusion directions shall be supported.

Figure 170 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 170 — Beam swept solid

Figure 171 illustrates the use of non-perpendicular extrusion to create the IfcExtrudedAreaSolid.

Figure 171 — Beam non-perpendicular extrusion

Exchange
Import		O
Export		O

Body AdvancedSweptSolid Geometry

The Body AdvancedSweptSolid Geometry concept applies to this entity.

The following additional constraints apply to the 'AdvancedSweptSolid' representation type:

Solid: IfcSurfaceCurveSweptAreaSolid, IfcFixedReferenceSweptAreaSolid, IfcExtrudedAreaSolidTapered, IfcRevolvedAreaSolidTapered shall be supported.
NOTE View definitions and implementer agreement can further constrain the allowed swept solid types.
Profile: see 'SweptSolid' geometric representation
Extrusion: not applicable

Exchange
Import		O
Export		O

Body SweptSolid ParameterizedProfile Geometry

The Body SweptSolid ParameterizedProfile Geometry concept applies to this entity.

Figure 171 illustrates usage of IfcExtrudedAreaSolid having IfcTShapeProfileDef to represent a cap-beam of a concrete box girder bridge. Note that the direction of extrusion does not necessarily correspond with the direction of load transfer such as in this case.

Figure 171 — Bridge cap beam geometry

Exchange
Import		O
Export		O

Element Decomposition

The Element Decomposition concept applies to this entity as shown in Table 24.

RelatedObjects	Description
IfcReinforcingBar	Rebar for concrete girders
IfcTendon	Tendons for concrete girders
IfcTendonAnchor	Tendor anchors for concrete girders

Table 24 — IfcBeam Element Decomposition

As shown in Figure 172, concrete box girders may contain components for rebar. Each IfcReinforcingElement corresponds to a particular bending shape and configuration (defined at the linked IfcReinforcingElementType having geometry defined by IfcSweptDiskSolidPolygonal) placed multiple times along a pattern, where each placement instance is defined using IfcMappedItem.

Figure 172 — Bridge girder components

Exchange
Import		O
Export		O

Annotation 2D Geometry

The Annotation 2D Geometry concept applies to this entity as shown in Table 25.

Identifier	Type	Items	Description
		IfcTextLiteralWithExtent	Piece marks.
		IfcCartesianPoint	Pop marks.
		IfcIndexedPolyCurve	Contour marks.

Table 25 — IfcBeam Annotation 2D Geometry

For fabrication, piece marks, pop marks, and contour marks may be designated using the 'Annotation' representation.

Exchange
Import				O
Export				O

Path Connectivity

The Path Connectivity concept applies to this entity.

Connectivity to other elements, including adjoining girder segments on each end and stiffeners along, this relationship may be used.

Stiffeners are represented using IfcPlate, where a single instance of IfcPlate may be used for each side of the web of component beams to capture all placements, where IfcMappedItem geometry indicates the positioning for each repetition. The spacing of stiffeners may also be captured parametrically within the IfcTable at IfcBeam. The IfcPlate is connected to the component IfcBeam using IfcRelConnectsElements where RelatingElement refers to the IfcBeam.

Shear studs are represented using IfcMember, where a single instance of IfcMember may be used corresponding to each IfcBeam component, where IfcMappedItem geometry indicates the positioning for each repetition. The spacing of shear studs may also be captured parametrically within the IfcTable at IfcBeam. The IfcMember is connected to the component IfcBeam using IfcRelConnectsElements where RelatingElement refers to the IfcBeam.

Exchange
Import		R
Export		R

Element Positioning

The Element Positioning concept applies to this entity as shown in Table 26.

Placement	Transform	Description
VERTICAL	WARP	Bridge girders are positioned and transformed to follow the alignment curve.
VERTICAL	PLACE	Bridge cap beams and diaphragms are positioned without transformation.

Table 26 — IfcBeam Element Positioning

Exchange
Import		O	O	O
Export		O	O	O

Concept inheritance

#	Concept	Model View
IfcRoot
	Software Identity	Bridge View
	User Identity	Bridge View
	Object Ownership	Bridge View
IfcObject
	Property Sets for Objects	Bridge View
IfcElement
	Element Occurrence Attributes	Bridge View
	Product Local Placement	Bridge View
	Product Assignment	Bridge View
IfcBeam
	Object Typing	Bridge View
	Quantity Sets	Bridge View
	Material Profile Set	Bridge View
	Constraint Association	Bridge View
	Structural Curve Assignment	Bridge View
	Axis 3D Geometry	Bridge View
	Body SweptSolid Geometry	Bridge View
	Body AdvancedSweptSolid Geometry	Bridge View
	Body SweptSolid ParameterizedProfile Geometry	Bridge View
	Element Decomposition	Bridge View
	Annotation 2D Geometry	Bridge View
	Path Connectivity	Bridge View
	Element Positioning	Bridge View

Formal representations

XSD Specification

 <xs:element name="IfcBeam" type="ifc:IfcBeam" substitutionGroup="ifc:IfcBuildingElement" nillable="true"/>

 <xs:complexType name="IfcBeam">

  <xs:complexContent>

   <xs:extension base="ifc:IfcBuildingElement">

    <xs:attribute name="PredefinedType" type="ifc:IfcBeamTypeEnum" use="optional"/>

   </xs:extension>

  </xs:complexContent>

 </xs:complexType>

EXPRESS Specification


ENTITY IfcBeam

 SUBTYPE OF (IfcBuildingElement);

  PredefinedType : OPTIONAL IfcBeamTypeEnum;

 WHERE

  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[1].RelatingType));
END_ENTITY;

 EXPRESS-G diagram

Link to this page

Item	Change	Description
IFC2x3 to IFC4
IfcBeam
OwnerHistory	MODIFIED	Instantiation changed to OPTIONAL.
PredefinedType	ADDED
IFC4x1 to IFC4x2
IfcBeam
PositionedFrom	ADDED

	Balken / Unterzug
	Beam
	Poutre

IfcBeam

Semantic definitions at the entity

Inherited definitions from supertypes

Definitions applying to Bridge View

Formal representations