IFC 4.3.0.1 (IFC4X3) development

7.10.3.16 IfcStructuralLoadGroup

7.10.3.16.1 Semantic definition

The entity IfcStructuralLoadGroup is used to structure the physical impacts. By using the grouping features inherited from IfcGroup, instances of IfcStructuralAction (or its subclasses) and of IfcStructuralLoadGroup can be used to define load groups, load cases and load combinations. (See also IfcLoadGroupTypeEnum.)

Informal Propositions:

  1. Load groups of type LOAD_GROUP shall only contain instances of IfcStructuralAction.
  2. Load groups of type LOAD_CASE shall always be instantiated from the subtype IfcStructuralLoadCase, not directly from the generic type IfcStructuralLoadGroup itself.
  3. Instances of IfcStructuralLoadCase shall only contain instances of IfcStructuralAction or/ and instances of IfcStructuralLoadGroup of type LOAD_GROUP.
  4. Load groups of type LOAD_COMBINATION shall only contain instances of IfcStructuralLoadCase.

7.10.3.16.2 Entity inheritance

7.10.3.16.3 Attributes

# Attribute Type Description
IfcRoot (4)
1 GlobalId IfcGloballyUniqueId

Assignment of a globally unique identifier within the entire software world.

2 OwnerHistory OPTIONAL IfcOwnerHistory

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,

3 Name OPTIONAL IfcLabel

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.

4 Description OPTIONAL IfcText

Optional description, provided for exchanging informative comments.

IfcObjectDefinition (7)
HasAssignments SET [0:?] OF IfcRelAssigns FOR RelatedObjects

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.

Nests SET [0:1] OF IfcRelNests FOR RelatedObjects

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 SET [0:?] OF IfcRelNests FOR RelatingObject

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).

HasContext SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions

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 SET [0:?] OF IfcRelAggregates FOR RelatingObject

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).

Decomposes SET [0:1] OF IfcRelAggregates FOR RelatedObjects

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).

HasAssociations SET [0:?] OF IfcRelAssociates FOR RelatedObjects

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.

IfcObject (5)
5 ObjectType OPTIONAL IfcLabel

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.

IsDeclaredBy SET [0:1] OF IfcRelDefinesByObject FOR RelatedObjects

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.

Declares SET [0:?] OF IfcRelDefinesByObject FOR RelatingObject

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.

IsTypedBy SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects

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.

IsDefinedBy SET [0:?] OF IfcRelDefinesByProperties FOR RelatedObjects

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.

IfcGroup (2)
IsGroupedBy SET [0:?] OF IfcRelAssignsToGroup FOR RelatingGroup

Reference to the relationship IfcRelAssignsToGroup that assigns the one to many group members to the IfcGroup object.

ReferencedInStructures SET [0:?] OF IfcRelReferencedInSpatialStructure FOR RelatedElements

No description available.

Click to show 18 hidden inherited attributes Click to hide 18 inherited attributes
IfcStructuralLoadGroup (7)
6 PredefinedType IfcLoadGroupTypeEnum

Selects a predefined type for the load group. It can be differentiated between load groups, load cases, load combinations, or userdefined grouping levels.

7 ActionType IfcActionTypeEnum

Type of actions in the group. Normally needed if 'PredefinedType' specifies a LOAD_CASE.

8 ActionSource IfcActionSourceTypeEnum

Source of actions in the group. Normally needed if 'PredefinedType' specifies a LOAD_CASE.

9 Coefficient OPTIONAL IfcRatioMeasure

Load factor. If omitted, a factor is not yet known or not specified. A load factor of 1.0 shall be explicitly exported as Coefficient = 1.0.

10 Purpose OPTIONAL IfcLabel

Description of the purpose of this instance. Among else, possible values of the Purpose of load combinations are 'SLS', 'ULS', 'ALS' to indicate serviceability, ultimate, or accidental limit state.

SourceOfResultGroup SET [0:1] OF IfcStructuralResultGroup FOR ResultForLoadGroup

Results which were computed using this load group.

LoadGroupFor SET [0:?] OF IfcStructuralAnalysisModel FOR LoadedBy

Analysis models in which this load group is used.

Table 7.10.3.16.A

7.10.3.16.4 Formal propositions

Name Description
HasObjectType

The attribute ObjectType shall be given if the predefined type, action type, or action source is set to USERDEFINED.

(
  (PredefinedType <> IfcLoadGroupTypeEnum.USERDEFINED) AND
  (ActionType <> IfcActionTypeEnum.USERDEFINED) AND
  (ActionSource <> IfcActionSourceTypeEnum.USERDEFINED)
) OR EXISTS(SELF\IfcObject.ObjectType)
Table 7.10.3.16.B

7.10.3.16.5 Property sets

  • Pset_Risk
    • RiskName
    • RiskType
    • NatureOfRisk
    • RiskAssessmentMethodology
    • UnmitigatedRiskLikelihood
    • UnmitigatedRiskConsequence
    • UnmitigatedRiskSignificance
    • MitigationPlanned
    • MitigatedRiskLikelihood
    • MitigatedRiskConsequence
    • MitigatedRiskSignificance
    • MitigationProposed
    • AssociatedProduct
    • AssociatedActivity
    • AssociatedLocation

7.10.3.16.6 Concept usage

Concept Usage Description
IfcRoot (2)
Revision Control General

Ownership, history, and merge state is captured using IfcOwnerHistory.

Software Identity General

IfcRoot assigns the globally unique ID. In addition it may provide for a name and a description about the concept.

IfcObjectDefinition (9)
Aggregation General

No description available.

Approval Association General

No description available.

Classification Association General

Any object occurrence or object type can have a reference to a specific classification reference, i.e. to a particular facet within a classification system.

Constraint Association General

No description available.

Document Association General

No description available.

Library Association General

No description available.

Material Association General

No description available.

Material Single General

No description available.

Nesting General

No description available.

IfcObject (5)
Assignment to Group General

No description available.

Object Predefined Type General

No description available.

Object Typing General

Any object occurrence can be typed by being assigned to a common object type utilizing this concept. A particular rule, restricting the applicable subtypes of IfcTypeObject that can be assigned, is introduced by overriding this concept at the level of subtypes of IfcObject.

This concept can be applied to the following resources:

Object User Identity General

An attribute Name and optionally Description can be used for all subypes of IfcObject. For those subtypes, that have an object type definition, such as ifcBeam - IfcBeamType, the common Name and optionally Description is associated with the object type.

Property Sets with Override General

Any object occurrence can hold property sets, either directly at the object occurrence as element specific property sets, or at the object type, as type property sets. In this case, the properties that are provided to the object occurrence are the combinations of element specific and type properties. In case, that the same property (within the same property set, is defined both, in occurrence and type properties, the property value of the occurrence property overrides the property value of the type property.

IfcGroup (2)
Group Assignment General

The IfcGroup establishes an arbitrary collection of objects through utilizing this concept.

Property Sets for Objects General

This concept can be applied to the following resources:

Click to show 18 hidden inherited concepts Click to hide 18 inherited concepts
Table 7.10.3.16.C

7.10.3.16.7 Formal representation

ENTITY IfcStructuralLoadGroup
 SUPERTYPE OF (ONEOF
	(IfcStructuralLoadCase))
 SUBTYPE OF (IfcGroup);
	PredefinedType : IfcLoadGroupTypeEnum;
	ActionType : IfcActionTypeEnum;
	ActionSource : IfcActionSourceTypeEnum;
	Coefficient : OPTIONAL IfcRatioMeasure;
	Purpose : OPTIONAL IfcLabel;
 INVERSE
	SourceOfResultGroup : SET [0:1] OF IfcStructuralResultGroup FOR ResultForLoadGroup;
	LoadGroupFor : SET [0:?] OF IfcStructuralAnalysisModel FOR LoadedBy;
 WHERE
	HasObjectType : (
  (PredefinedType <> IfcLoadGroupTypeEnum.USERDEFINED) AND
  (ActionType <> IfcActionTypeEnum.USERDEFINED) AND
  (ActionSource <> IfcActionSourceTypeEnum.USERDEFINED)
) OR EXISTS(SELF\IfcObject.ObjectType);
END_ENTITY;

7.10.3.16.8 References

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7.10.3.16.9 Changelog

  • where rule, HasObjectType