Usage of IfcFacilityPartCommon

Users IFC
,
1

In the US, we’ve proposed the following update to hierarchical structure for bridges:

new proposed IFC hierarchical breakdown
new proposed IFC hierarchical breakdown2482×1363 167 KB

I am trying to confirm that this is permissible under the schema and the AbV. The question is whether this is an acceptable use of IfcFacilityPartCommon, being there is no IfcFacilty>IfcFaciltyPart as an umbrella to them, but being directly “bound” to the IfcSite.

2

Now, I’m not hindered by any knowledge on bridges, but I think in which you phrase the question there is indeed some tension:

  • FacilityPart without a Facility
  • Lack of provenance that e.g the approach-structure belongs to the bridge. In larger geospatial contexts wouldn’t you prefer a shared ancestor other than site?
  • I can’t tell, but PartCommon is for “shared responsibilities in multiple domains”, is that the case in all these 4 PartCommon cases?
3

Well, I’m dealing with a US context specifically. From the input/feedback we’ve gotten from the state DOTs (AASHTO members) is:

Yes, this is my big question… do I need to declare an IfcFacility before I can use IfcFacilityPartCommon? Assuming that I can have multiple facilities (bridge, road, railway, building, port/waterway) on the same site, within the same project, how best to use FacilityPartCommon which is meant to span/cross Facilities? Is it required to belong to one or the other, or is it meant to be a “free-agent”, or Limbo, for constructions that work.

From the online documentation of IfcFacilityPartCommon:

5.4.3.27.1 Semantic definition

A part that is not clearly part of one domain but is a hybrid and has shared responsibilities in multiple domains.
For example ‘Level crossing’, ‘junctions’, etc. See the enums for more examples.

So, I’m assuming I can use IfcFacilityPartCommon, without an IfcFacility as proposed above.

Approaches, Retaining Structures, and Slope Protection are NOT considered integral to the bridge, but are important complementary structures. How they get designed and built often varies by jurisdiction, but they are structures that do need to be part of the overall project documentation.

Culverts are a bit trickier and we are continuing to sort this out. Our tendency is to treat them like the others.

Thus, while these structures are not explicitly “bridge parts”, they will be part of the larger road infrastructure network. Thus, the desire to put them in the same project, on the same site, but NOT within the spatial container of the bridge.