Dear Sir / Madam,
We thank you for your valuable feedback.
Here are the project team’s responses to your remarks:
Do you have a plan for implementing IFC Bridge in the different national management systems? How can we implement the classifications in our management system in IFC Bridge?
As an international project, we do not have the resources for implementing IfcBridge in the different national management systems. This task remains for the national authorities. However, the Infra Rooms will setup a deployment project. If you join this project you will get support in implementing the standard in your national maintenance system.
IfcBridge does not provide a fine-grained classification. Instead it makes sure that reading and writing applications make consistent use of the provided entities for transporting bridge information. However, there a well-defined mechanisms to integrate national classification systems with IFC, using property sets and specific IFC entities (IfcClassification). A detailed explanation can be found in the IFC Infra Overall Architecture Report, pp. 32-35.
- The interface between geotechnics and bridge is a challenge in current models (and in the design control), and this issue needs to be solved. What about backfilling, frost protection, scour protection, sheet pile and how is this implemented in IFC Bridge? Is this covered by Common Schema?
Yes, the Common Schema project is developing data structures covering theses aspects. We have forwarded any requirements regarding Soil and Geotechnics from the bridge domain to Common Schema.
How can we implement these installations in IFC Bridge?
Road equipment will be covered by IfcRoad. Some of the equipment objects are covered by the IFC schema already, such as IfcRailing, for example. In any case, you will be ale to use proxy objects and associate them with a national classification.
3.Tunnel portals, retaining walls, ferry quays and avalanche protection: Portals, retaining walls (height > 5 m), ferry quays and avalanche protection are considered as load-bearing structures/bridges in Norway. How should we implement and adapt these construction types to IFC Bridge?
The project team does not agree that all of the mentioned constructions are bridges. However, it is possible to model everything in IFC, if you use generic types and placeholders, such as IfcFacility and IfcBuildingElementProxy. You are advised to make use of “user-defined types” and the aforementioned possibilities to use national classification systems.
- Composite and wooden bridges: We have several composite and timber bridges in Norway. How is IFC Bridge adapted to these materials? What about unique details, components, joints for these bridges?
It is possible to assign all kinds of materials to individual components. Details and joints: On the semantic side, makes use if IfcMechanicalFastener and associate it with your classification. In the requirements analysis conducted in WP1 (finished in 01/2018) it was decided (and approved by the expert panel) not to include wooden bridges in the scope of the fast-track IfcBridge project. However, we believe that you are able to model these bridges in IFC.
- Modelling of details. Today different details that are crucial for verification/approval work we do, are modelled. Some are listed below. How do you recommend to model these details in IFC Bridge?
This question is a too detailed to be answered in this forum. If you join the Deployment project, you will get the required support. Most of the details can be modelled geometrically and combined with existing semantic classes.
- Railing/Parapets/barriers: We have different types of railings in Norway. Examples are railing for roads, bridges (including barriers preventing snow from falling down on underlying roads), pathways, rail over railroad, noise barriers, etc. Should this be different types of railing?
All rails can be described using IfcRailing. More detailed requirements can be modelled by classifications. Geometry concepts are plentyful and standardized. We will produce sample files illustrating this.
- Does IFC Bridge differ on cast in place and prefabricated elements?
You can, but you do not have to. You can use the PropertySet Concrete Element General to define specific properties.
- How does IFC Bridge incorporate different construction stages?
This is only partially handled so far. You can assign schedule information to indvidual parts. However, construction stage deformations are not yet explicitely adressed (not in scope of IfcBridge 1.0). However, we propose to use different models for each construction stage.
- How are the axes of the bridge defined in IFC Bridge?
You can use IfcAligment(s) and define additional reference lines (axes) by means of offsets, for example.
- We cannot find any information about movable or floating bridges. Are those within the scope of IFC Bridge?
No, not in the IfcBridge 1.0 Fast Track Project.
The IfcBridge project team