Stab / Stabträger

An IfcMember is a structural member designed to carry loads between or beyond points of support. It is not required to be load bearing. The orientation of the member (being horizontal, vertical or sloped) is not relevant to its definition (in contrary to IfcBeam and IfcColumn). An IfcMember represents a linear structural element from an architectural or structural modeling point of view and shall be used if it cannot be expressed more specifically as either an IfcBeam or an IfcColumn.

NOTE  The representation of a member in a structural analysis model is provided by IfcStructuralCurveMember being part of an IfcStructuralAnalysisModel.

The IFC specification provides two entities for member occurrences:

HISTORY  New entity in IFC2x2 Addendum 1.

Common Use Definitions

The following concepts are inherited at supertypes:

 Instance diagram

Object Typing

The Object Typing concept applies to this entity as shown in Table 126.

Table 126 — IfcMember Object Typing

Property Sets for Objects

The Property Sets for Objects concept applies to this entity as shown in Table 127.

Table 127 — IfcMember Property Sets for Objects

Quantity Sets

The Quantity Sets concept applies to this entity as shown in Table 128.

Table 128 — IfcMember Quantity Sets

Material Profile Set

The Material Profile Set concept applies to this entity.

The material of the IfcMember is defined by the IfcMaterialProfileSet or as fallback by IfcMaterial, and it is attached either directly or at the IfcMemberType.

NOTE  It is illegal to assign an IfcMaterialProfileSetUsage to an IfcMember. Only the subtype IfcMemberStandardCase supports this concept.

Spatial Containment

The Spatial Containment concept applies to this entity as shown in Table 129.
IfcBuildingStoreyDefault spatial container
IfcBuildingSpatial container for the element if it cannot be assigned to a building storey
IfcSiteSpatial container for the element in case that it is placed on site (outside of building)

Table 129 — IfcMember Spatial Containment

The IfcMember, as any subtype of IfcBuildingElement, may participate alternatively in one of the two different containment relationships:

Axis 3D Geometry

The Axis 3D Geometry concept applies to this entity as shown in Table 130.
AxisCurve3DIfcBoundedCurveThree-dimensional reference curve for the member.

Table 130 — IfcMember Axis 3D Geometry

The axis representation can be used to represent the system length of a member that may extent the body length of the member.

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

Body SweptSolid Geometry

The Body SweptSolid Geometry concept applies to this entity.

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

Figure 188 illustrates a '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).

standard member

Figure 188 — Member swept solid

Body AdvancedSweptSolid Geometry

The Body AdvancedSweptSolid Geometry concept applies to this entity.

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

MappedRepresentation Representation Type

Body Clipping Geometry

The Body Clipping Geometry concept applies to this entity.

The following constraints apply to the 'Clipping' representation:

Figure 189 illustrates a 'Clipping' geometric representation with use of IfcBooleanClippingResult between an IfcExtrudedAreaSolid and an IfcHalfSpaceSolid to create a clipped body.

clipped member

Figure 189 — Member clipping

Product Assignment

The Product Assignment concept applies to this entity as shown in Table 131.
IfcStructuralCurveMemberAn idealized structural member corresponding to the member.
IfcTaskA task for operating on the member.

Table 131 — IfcMember Product Assignment

XSD Specification:

 <xs:element name="IfcMember" type="ifc:IfcMember" substitutionGroup="ifc:IfcBuildingElement" nillable="true"/>
 <xs:complexType name="IfcMember">
   <xs:extension base="ifc:IfcBuildingElement">
    <xs:attribute name="PredefinedType" type="ifc:IfcMemberTypeEnum" use="optional"/>

EXPRESS Specification:

ENTITY IfcMember
SUPERTYPE OF(IfcMemberStandardCase)
SUBTYPE OF IfcBuildingElement;
PredefinedType : OPTIONAL IfcMemberTypeEnum;
CorrectPredefinedType : NOT(EXISTS(PredefinedType)) OR (PredefinedType <> IfcMemberTypeEnum.USERDEFINED) OR ((PredefinedType = IfcMemberTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
CorrectTypeAssigned : (SIZEOF(IsTypedBy) = 0) OR ('IFCSHAREDBLDGELEMENTS.IFCMEMBERTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));

Link to EXPRESS-G diagram EXPRESS-G diagram

Attribute Definitions:

PredefinedType : Predefined generic type for a member that is specified in an enumeration. There may be a property set given for the predefined types.
NOTE  The PredefinedType shall only be used, if no IfcMemberType is assigned, providing its own IfcMemberType.PredefinedType.
IFC4 CHANGE The attribute has been added at the end of the entity definition.

Formal Propositions:

CorrectPredefinedType : Either the PredefinedType attribute is unset (e.g. because an IfcMemberType is associated), or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.
CorrectTypeAssigned : Either there is no member type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcMemberType.

Inheritance Graph:

ENTITY IfcMember
GlobalId : IfcGloballyUniqueId;
OwnerHistory : OPTIONAL IfcOwnerHistory;
Name : OPTIONAL IfcLabel;
Description : OPTIONAL IfcText;
ENTITY IfcObjectDefinition
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 IfcLabel;
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;
ReferencedBy : SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcElement
Tag : OPTIONAL IfcIdentifier;
FillsVoids : SET [0:1] OF IfcRelFillsElement FOR RelatedBuildingElement;
ConnectedTo : SET OF IfcRelConnectsElements FOR RelatingElement;
IsInterferedByElements : SET OF IfcRelInterferesElements FOR RelatedElement;
InterferesElements : SET OF IfcRelInterferesElements FOR RelatingElement;
HasProjections : SET OF IfcRelProjectsElement FOR RelatingElement;
ReferencedInStructures : SET OF IfcRelReferencedInSpatialStructure FOR RelatedElements;
HasOpenings : SET OF IfcRelVoidsElement FOR RelatingBuildingElement;
IsConnectionRealization : SET OF IfcRelConnectsWithRealizingElements FOR RealizingElements;
ProvidesBoundaries : SET OF IfcRelSpaceBoundary FOR RelatedBuildingElement;
ConnectedFrom : SET OF IfcRelConnectsElements FOR RelatedElement;
ContainedInStructure : SET [0:1] OF IfcRelContainedInSpatialStructure FOR RelatedElements;
ENTITY IfcBuildingElement
HasCoverings : SET OF IfcRelCoversBldgElements FOR RelatingBuildingElement;
ENTITY IfcMember
PredefinedType : OPTIONAL IfcMemberTypeEnum;

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