IfcStructuralAction

Natural language names
Belastung / Einwirkung (allgemein)
Structural Action
Action structurelle
Semantic definitions at the entity
Entity definition

A structural action is a structural activity that acts upon a structural item or building element.

HISTORY  New entity in IFC2x2.
IFC4 CHANGE  Attribute DestabilizingLoad made optional. Attribute CausedBy deleted; use IfcRelAssignsToProduct via ReferencedBy instead.

Relationship use definition

Structural actions are grouped into either an IfcStructuralLoadGroup of predefined type LOAD_GROUP or, more often, an IfcStructuralLoadCase. This is accomplished via the inverse relationship HasAssignments and an IfcRelAssignsToGroup relationship object. IfcStructuralLoadGroup.LoadGroupFor or IfcStructuralLoadCase.LoadGroupFor respectively refers to the structural analysis model(s) in which the loads are used.

It is furthermore possible to establish relationships between actions in one analysis model and reactions in another analysis model which cause the actions. For example, a support reaction from one structural system may be taken over as a load onto another supporting structural system. This is expressed by means of the inverse relationship ReferencedBy of the action and an IfcRelAssignsToProduct relationship object. IfcRelAssignsToProduct.Name is set to 'Causes' and IfcRelAssignsToProduct.RelatedObjects refers to an instance of a subtype of IfcStructuralReaction.

Attribute definitions
#AttributeTypeCardinalityDescription G
10DestabilizingLoadIfcBoolean? Indicates if this action may cause a stability problem. If it is 'FALSE', no further investigations regarding stability problems are necessary. X
Inherited definitions from supertypes
Entity inheritance IfcStructuralCurveAction IfcStructuralPointAction IfcStructuralSurfaceAction IfcStructuralActivity IfcProduct IfcObject IfcObjectDefinition IfcRoot
Attribute inheritance
#AttributeTypeCardinalityDescriptionG
IfcRoot
1GlobalIdIfcGloballyUniqueId Assignment of a globally unique identifier within the entire software world. X
2OwnerHistoryIfcOwnerHistory? 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.
IFC4 CHANGE  The attribute has been changed to be OPTIONAL.
X
3NameIfcLabel? 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
4DescriptionIfcText? Optional description, provided for exchanging informative comments.X
IfcObjectDefinition
HasAssignmentsIfcRelAssigns
@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
NestsIfcRelNests
@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).
IFC4 CHANGE  The inverse attribute datatype has been added and separated from Decomposes defined at IfcObjectDefinition.
X
IsNestedByIfcRelNests
@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).
IFC4 CHANGE  The inverse attribute datatype has been added and separated from IsDecomposedBy defined at IfcObjectDefinition.
X
HasContextIfcRelDeclares
@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.
IFC4 CHANGE  The inverse attribute datatype has been added.
X
IsDecomposedByIfcRelAggregates
@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).
IFC4 CHANGE  The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.
X
DecomposesIfcRelAggregates
@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).
IFC4 CHANGE  The inverse attribute datatype has been changed from the supertype IfcRelDecomposes to subtype IfcRelAggregates.
X
HasAssociationsIfcRelAssociates
@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
5ObjectTypeIfcLabel? The type denotes a particular type that indicates the object further. The use has to be established at the level of instantiable subtypes. In particular it holds the user defined type, if the enumeration of the attribute PredefinedType is set to USERDEFINED.
X
IsDeclaredByIfcRelDefinesByObject
@RelatedObjects
S[0:1]Link to the relationship object pointing to the declaring object that provides the object definitions for this object occurrence. The declaring object has to be part of an object type decomposition. The associated IfcObject, or its subtypes, contains the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE  New inverse relationship, change made with upward compatibility for file based exchange.
X
DeclaresIfcRelDefinesByObject
@RelatingObject
S[0:?]Link to the relationship object pointing to the reflected object(s) that receives the object definitions. The reflected object has to be part of an object occurrence decomposition. The associated IfcObject, or its subtypes, provides the specific information (as part of a type, or style, definition), that is common to all reflected instances of the declaring IfcObject, or its subtypes.
IFC4 CHANGE  New inverse relationship, change made with upward compatibility for file based exchange.
X
IsTypedByIfcRelDefinesByType
@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.
IFC4 CHANGE  New inverse relationship, the link to IfcRelDefinesByType had previously be included in the inverse relationship IfcRelDefines. Change made with upward compatibility for file based exchange.
X
IsDefinedByIfcRelDefinesByProperties
@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.
IFC4 CHANGE  The data type has been changed from IfcRelDefines to IfcRelDefinesByProperties with upward compatibility for file based exchange.
X
IfcProduct
6ObjectPlacementIfcObjectPlacement? 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
7RepresentationIfcProductRepresentation? 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
ReferencedByIfcRelAssignsToProduct
@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
PositionedRelativeToIfcRelPositions
@RelatedProducts
S[0:1]X
IfcStructuralActivity
8AppliedLoadIfcStructuralLoad Load or result resource object which defines the load type, direction, and load values.

In case of activities which are variably distributed over curves or surfaces, IfcStructuralLoadConfiguration is used which provides a list of load samples and their locations within the load distribution, measured in local coordinates of the curve or surface on which this activity acts. The contents of this load or result distribution may be further restricted by definitions at subtypes of IfcStructuralActivity.

X
9GlobalOrLocalIfcGlobalOrLocalEnum Indicates whether the load directions refer to the global coordinate system (global to the analysis model, i.e. as established by IfcStructuralAnalysisModel.SharedPlacement) or to the local coordinate system (local to the activity or connected item, as established by an explicit or implied representation and its parameter space).
NOTE, the informal definition of IfcRepresentationResource.IfcGlobalOrLocalEnum doe s not distinguish between "global coordinate system" and "world coordinate system". On the other hand, this distinction is necessary in the IfcStructuralAnalysisDomain where the shared "global" coordinate system of an analysis model may very well not be the same as the project-wide world coordinate system.
NOTE  In the scope of IfcStructuralActivity.GlobalOrLocal, the meaning of GLOBAL_COORDS is therefore not to be taken as world coordinate system but as the analysis model specific shared coordinate system. In contrast, LOCAL_COORDS is to be taken as coordinates which are local to individual structural items and activities, as established by subclass-specific geometry use definitions.
X
AssignedToStructuralItemIfcRelConnectsStructuralActivity
@RelatedStructuralActivity
S[0:1]Reference to the IfcRelConnectsStructuralActivity relationship by which activities are connected with structural items.X
IfcStructuralAction
10DestabilizingLoadIfcBoolean? Indicates if this action may cause a stability problem. If it is 'FALSE', no further investigations regarding stability problems are necessary. X
Definitions applying to General Usage

Concept inheritance

#ConceptTemplateModel View
IfcRoot
IdentitySoftware IdentityGeneral Usage
Revision ControlRevision ControlGeneral Usage
IfcObjectDefinition
Classification AssociationClassification AssociationGeneral Usage
IfcObject
Object User IdentityObject User IdentityGeneral Usage
Object Predefined TypeObject Predefined TypeGeneral Usage
Object TypingObject TypingGeneral Usage
Property Sets for ObjectsProperty Sets for ObjectsGeneral Usage
Property Sets with OverrideProperty Sets with OverrideGeneral Usage
IfcProduct
Product PlacementProduct PlacementGeneral Usage
Product Geometric RepresentationProduct Geometric RepresentationGeneral Usage
Formal representations
XML Specification
 <xs:element name="IfcStructuralAction" type="ifc:IfcStructuralAction" abstract="true" substitutionGroup="ifc:IfcStructuralActivity" nillable="true"/>
 <xs:complexType name="IfcStructuralAction" abstract="true">
  <xs:complexContent>
   <xs:extension base="ifc:IfcStructuralActivity">
    <xs:attribute name="DestabilizingLoad" type="ifc:IfcBoolean" use="optional"/>
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
EXPRESS Specification
ENTITY IfcStructuralAction
 ABSTRACT SUPERTYPE OF(ONEOF(IfcStructuralCurveAction, IfcStructuralPointAction, IfcStructuralSurfaceAction))
 SUBTYPE OF (IfcStructuralActivity);
  DestabilizingLoad : OPTIONAL IfcBoolean;
END_ENTITY;

Link to EXPRESS-G diagram EXPRESS-G diagram

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