Floor slab

Definition

The concept of 'Floor slab' defines a horizontal slab that is used as a floor, there are separate concepts for ramps and roof slabs. The concept of 'Layered structure (material layers)' is used to define the structure of the floor slab.

Geometry

Geometry type	Extrusion	Profile	Segments	Clipped	Slanted
BoundingBox
Extruded solid	Linear	Rectangular	1	No	No
Extruded solid	Linear	Arbitrary	1	No	No
Extruded solid	Linear	Curved	1	No	No
Brep

• Not slanted in the context of floor slabs means, that the extrusion is in the direction of the global Z-axis
• As the basic representation floor slabs should always have a bounding box. The bounding box can be used as a place holder for floor slabs with complex geometry in programs that are not able to support the given geometry. This could be the case e.g. in programs that don't support floor slabs with curved boundaries or Brep representation.
• Floor slabs that are horizontal and have an even top and bottom surface are transferred using an extruded solid.
  • Floor slabs may not be clipped. If the top or bottom surfaces are not even or the edges are not perpendicular to the surface Brep geometry should be used instead.
  • Openings into floor slabs are made using the opening element.
  • In many programs it is possible to model e.g. stairs by using the floor slab object for the stair steps. This kind of 'misuse' should be avoided, because when the model is used for analysis purposes this will most probably lead to an incorrect result in the analysis.
  • The floor slab provided by the architect (using architectural CAD) is mostly an approximation and the structural engineer determines the final shape and composition of the floor slab(s) based on that approximation. This consideration relaxes the requirements that are set for the floor slabs in the current IFC exchange scenarios.
  • When solids are used for the floor slab geometry the exchange files are more compact and it is easier to get the generic shape of the floor slab.
• In all other cases the floor slab representation is made using a Brep
  • Clipped floor slabs.
  • Floor slabs with a profile that can't be expressed by IfcCompositeCurve. The vocabulary of the composite curve contains the following elements: straight segment, circular arc and elliptical arc
  • Slanted floor slabs (It should be considered to use a ramp instead.)
  • Floor slabs that have a structured top or bottom surface.

Used by views

• Arch. design >> Quantities take off
• Arch. design >> Thermal load calculations / HVAC system design
• CAD / visualization

Data structure

IfcSlab
GlobalId
OwnerHistory
Owner history [all]
Label
UserDefinedType
PartOfGroups
Grouping [1,2]
IsContainedBy
Containment [all]
RelatingObject
Building storey [all]
IsDefinedBy
Dynamic property assignment [all]
RelatingPropertyDefinition
PropertySet system [all]
HasProperties
Common slab properties [1,3]
LocalPlacement
Relative placement [all]
PlacementRelTo
Building storey [all]
Representations
Geometric representation [all]
Items
Bounding box geometry [all]
Extruded solid: rectangular [1,3,5]
Extruded solid: arbitrary [all]
Extruded solid: curved [1,2,3,5]
Extruded solid: rectangular, clipped [3,5]
Extruded solid: arbitrary, clipped [3,5]
Extruded solid: curved, clipped [3,5]
Brep geometry [3,5]
Classification
Classification assignment [none]
Classifications
Classification [none]
HasOpenings
Voids element [1,3,5]
RelatedOpeningElement
Opening element [1,3,5]
PredefinedType
IfcSlabTypeEnum
Floor
LayerInformation
Layered structure (material layers) [1,3,5]
calcSlabArea
calcSlabVolume

Uses concepts

Bounding box geometry [all]
Brep geometry [3,5]
Building storey [all]
Classification [none]
Classification assignment [none]
Common slab properties [1,3]
Containment [all]
Dynamic property assignment [all]
Extruded solid: arbitrary [all]
Extruded solid: arbitrary, clipped [3,5]
Extruded solid: curved [1,2,3,5]
Extruded solid: curved, clipped [3,5]
Extruded solid: rectangular [1,3,5]
Extruded solid: rectangular, clipped [3,5]
Geometric representation [all]
Grouping [1,2]
Layered structure (material layers) [1,3,5]
Opening element [1,3,5]
Owner history [all]
PropertySet system [all]
Relative placement [all]
Voids element [1,3,5]

Used by concepts

Building storey
Opening element

Copyright © 2000-2002 BLIS-Project [BLIS, Registered Organization]
Author: Jiri Hietanen (jiri@blis-project.org)
All rights reserved.