IfcStructuralLinearAction

Definition from IAI: Instances of the entity IfcStructuralLinearAction are used to define constant linear actions. Structural loads applicable to linear actions are IfcStructuralLoadLinearForce and IfcStructuralLoadTemperature.

The structural load, defining the linear action is given by the attribute AppliedLoad at the supertype IfcStructuralActivity. The coordinate system, in which the AppliedLoad is defined is given by the attribute ObjectPlacement at the supertype IfcProduct.

> HISTORY: New entity in Release IFC2x Edition 2.

Topology Use Definition

Special case: If applied to building elements, placement and representation of the structural action are often implied by those of the building elements and are therefore optional for the actions.

Standard case: If applied to structural items, instances of IfcStructuralLinearAction shall have a topology representation. It includes a placement and a product representation. The IfcProductRepresentation shall be given by an item of Representations being of type "IfcTopologyRepresentation".

Placement

The placement for IfcStructuralLinearAction is determined at its supertype IfcProduct. It is defined by the optional IfcObjectPlacement, referenced by ObjectPlacement at IfcProduct, which establishes, if given, the object coordinate system that is referenced by the applied load.

- If the ObjectPlacement attribute is omitted, then all topological representations are given directly in world coordinates.
- If the ObjectPlacement attribute is provided, then it establishes an object coordinate system for all topological representations which are given object coordinates.
  - If the PlacementRelTo relationship of IfcLocalPlacement is omitted, the object coordinate system is established within the world coordinate system.
  - If the PlacementRelTo relationship of IfcLocalPlacement is given, it shall point to the local placement of the same IfcSpatialStructureElement, which is used in the ContainedInStructure inverse attribute, or to a spatial structure element at a higher level, referenced by that.

Topology Representation

Instances of IfcStructuralLinearAction shall have a topology representation given by an edge with an optional additional geometric representation of the included curve. It can be provided by either

- IfcEdge
- IfcOrientedEdge
- IfcEdgeCurve

which should be the single item of IfcTopologyRepresentation.Items. If the topological item is not of type IfcEdgeCurve, a line connection is assumed between the two vertices of the edge.

EXPRESS specification:

ENTITY IfcStructuralLinearAction
SUPERTYPE OF | (IfcStructuralLinearActionVarying)
SUBTYPE OF ( | IfcStructuralAction);
ProjectedOrTrue | : | IfcProjectedOrTrueLengthEnum;
WHERE
WR61 | : | SIZEOF(['IFCSTRUCTURALLOADRESOURCE.IFCSTRUCTURALLOADLINEARFORCE', 'IFCSTRUCTURALLOADRESOURCE.IFCSTRUCTURALLOADTEMPERATURE'] * TYPEOF(SELF\IfcStructuralActivity.AppliedLoad)) = 1;
END_ENTITY;

Attribute definitions:

ProjectedOrTrue | : | Defines if the load values are given by using the length of the member on which they act (true length) or by using the projected length resulting from the loaded member and the global project coordinate system. It is only considered if the global project coordinate system is used, and if the action is of type IfcStructuralLinearAction or IfcStructuralPlanarAction.

Formal Propositions:

WR61 | : | A linear action should place either a linear force or a temperature force.

Inheritance graph

ENTITY IfcStructuralLinearAction;
ENTITY IfcRoot;
GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;
ENTITY IfcObjectDefinition;
INVERSE
HasAssignments | : | SET OF IfcRelAssigns FOR RelatedObjects;
IsDecomposedBy | : | SET OF IfcRelDecomposes FOR RelatingObject;
Decomposes | : | SET [0:1] OF IfcRelDecomposes FOR RelatedObjects;
HasAssociations | : | SET OF IfcRelAssociates FOR RelatedObjects;
ENTITY IfcObject;
ObjectType | : | OPTIONAL IfcLabel;
INVERSE
IsDefinedBy | : | SET OF IfcRelDefines FOR RelatedObjects;
ENTITY IfcProduct;
ObjectPlacement | : | OPTIONAL IfcObjectPlacement;
Representation | : | OPTIONAL IfcProductRepresentation;
INVERSE
ReferencedBy | : | SET OF IfcRelAssignsToProduct FOR RelatingProduct;
ENTITY IfcStructuralActivity;
AppliedLoad | : | IfcStructuralLoad;
GlobalOrLocal | : | IfcGlobalOrLocalEnum;
INVERSE
AssignedToStructuralItem | : | IfcRelConnectsStructuralActivity FOR RelatedStructuralActivity;
ENTITY IfcStructuralAction;
DestabilizingLoad | : | BOOLEAN;
CausedBy | : | OPTIONAL IfcStructuralReaction;
ENTITY IfcStructuralLinearAction;
ProjectedOrTrue | : | IfcProjectedOrTrueLengthEnum;
END_ENTITY;