#### 6.1.3.1 IfcBeam

| Balken / Unterzug
| Poutre

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

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:complexContent>
</xs:complexType>

EXPRESS Specification:

ENTITY IfcBeam

| SUBTYPE OF (IfcBuildingElement);

PredefinedType | : | OPTIONAL IfcStrippedOptional;

| 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;

Attribute Definitions:

Formal Propositions:

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.

Inheritance Graph:

ENTITY IfcBeam

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| ENTITY IfcObjectDefinition

| INVERSE

HasAssignments | : | SET OF IfcRelAssigns FOR RelatedObjects;
Nests | : | SET [0:1] OF IfcRelNests FOR RelatedObjects;
IsNestedBy | : | SET OF IfcRelNests FOR RelatingObject;
HasContext | : | SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy | : | SET OF IfcRelAggregates FOR RelatingObject;
Decomposes | : | SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations | : | SET OF IfcRelAssociates FOR RelatedObjects;

| ENTITY IfcObject

ObjectType | : | OPTIONAL IfcStrippedOptional;

| INVERSE

IsDeclaredBy | : | SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects;
Declares | : | SET OF IfcRelDefinesByObject FOR RelatingObject;
IsTypedBy | : | SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects;
IsDefinedBy | : | SET OF IfcRelDefinesByProperties FOR RelatedObjects;

| ENTITY IfcProduct

ObjectPlacement | : | OPTIONAL IfcObjectPlacement;
Representation | : | OPTIONAL IfcProductRepresentation;

| INVERSE

ReferencedBy | : | SET OF IfcRelAssignsToProduct FOR RelatingProduct;

| ENTITY IfcElement

Tag | : | OPTIONAL IfcStrippedOptional;

| INVERSE

ConnectedTo | : | SET OF IfcRelConnectsElements FOR RelatingElement;
IsInterferedByElements | : | SET OF IfcRelInterferesElements FOR RelatedElement;
InterferesElements | : | SET OF IfcRelInterferesElements FOR RelatingElement;
HasOpenings | : | SET OF IfcRelVoidsElement FOR RelatingBuildingElement;
ProvidesBoundaries | : | SET OF IfcRelSpaceBoundary FOR RelatedBuildingElement;
ConnectedFrom | : | SET OF IfcRelConnectsElements FOR RelatedElement;
ContainedInStructure | : | SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;

| ENTITY IfcBuildingElement

| INVERSE

| ENTITY IfcBeam

PredefinedType | : | OPTIONAL IfcStrippedOptional;

END_ENTITY;

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