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Defining Soil Properties in IFC 4.3

Hey all – we are a team that is in the process of adding IFC4.3 support for our bridge modeling/analysis program, a large portion of which deals with soil-structure interaction. As a result, our program offers users the ability to specify a wide range of soil properties. However, the property set Pset_SolidStratumCapacity, which is associated with the element type IFCSolidStratum, does not support many of the soil parameters that users are able to specify for a soil layer within our program. Some of these parameters are the subgrade modulus, mass modulus, and unconfined compressive strength of the soil layer.

We wanted to know if anyone has been successful in adding such properties to an IFC model. Is there perhaps another property set that we should be using? We checked all seven property sets associated with IFCSolidStratum and none of them contain the parameters that we need to add.

If there truly is no built-in support for these parameters, is there some kind of work around short of requesting that these properties be added to the schema? For instance, would we be able to create a custom property set?


I designed Pset_SolidStratumCapacity as part of the Ports and Waterways project as a first step in capturing information for sharing within the design/engineering/construction/use teams. There is also Pset_SolidStratumComposition for soil analysis values including the ISO standard terms (which is problematic because it uses mixed upper and lower case in English and French, but that may not be a problem in Russian). . The Tunnel team are collating ideas for improving and extending these property sets and hopefully one of that team will pick up on your message. meanwhile, you can of course invent your own property sets (just don’t call them Pset_…)!

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Nick, thanks for the response and background information on Pset_SolidStratumCapacity. The best approach for now would appear to be for us to use the property sets already within the IFC schema as much as possible, and resort to usage of custom property sets only when properties to be added are not present within the existing IFC schema. As two follow-up items from our end, where any feedback is welcomed:

  1. Besides the naming issue that you mentioned, are there any major pitfalls to us pushing forward with the approach of custom property sets (when necessary)? If it helps, we are using the xBIM toolkit to develop our IFC models.
  2. Is there any recommended point of contact to whom we could send (and discuss) potential new entries for improving/extending property sets pertaining to soil-structure interaction?

Thanks once more for the previous and any following responses!

Comment here, or email attn: Ifc Tunnel Project