A Framework for Digital Delivery of Infrastructure Projects

Thesis

Infrastructure project delivery is shifting from drawing-based PDF to data-based models. Here’s a framework for digital delivery that parallels the current state of affairs in the hopes of minimizing discomfort and speeding adoption.

Current state

The vast majority of my experience in heavy civil design and construction has been in my home state of Indiana. Therefore, I’ll use the Indiana Department of Transportation (INDOT) as my basis of discussion. Note that I’m not speaking on behalf of the department or trying to come off as an authoritative voice - just making observations for the sake of discussion.

PDF - based delivery

The vast majority of Plans, Specs & Estimates (PSE) are currently transacted via PDF. This is particularly the case if we focus specifically on plans. INDOT has never dictated or forced consultant designers to use a specific CADD platform. They do publish the resources of documentation of the Microstation / OpenRoads civil workspace that they use for in-house design, but consultants are not obligated to use it.

Plan submittals are required to be made via PDF and must adhere to certain criteria:

• maximum file size
• look and feel (fonts, lineweights, abbreviations)
• sheet naming and scales
• sheet titles and arrangement order
• sheet numbering for addendums, revisions and construction changes

The title sheet of each plan set has additional requirements:

• project identification - name, project number, route, description of the work, features crossed
• geospatial location - latitude and longitude
• construction Contract Number
• Des Number

Common, Open Format - IFC 4.3

Digital delivery is best accomplished via IFC 4.3. Like PDF, it is a published data format not proprietary to any specific software system or vendor. This means that there are multiple options for viewing model data - including those that are free (no cost) for read-only viewing.

This also means that there are multiple authoring tools available. Like the current state of affairs, designers have the ability to choose their preferred modeling platform for generating and checking design model data.

Lastly, like PDF, IFC is an ISO standard. Specifically, IFC 4.3 is currently in candidate status for final approval as an updated ISO standard, ensuring that model information in this format will continue to be accessible for multiple decades in the future.

Data must meet specific requirements

Information Delivery Specification

Information Delivery Specification (IDS) is a relative newcomer to the openBIM scene. IDS is a machine-readable specification that defines the digital governance requirements for an information exchange. You could think of this as Model View Definition (MVD) - lite.

You could also think of this as a BIM checklist that can be performed automatically by supporting software to validate IFC data against project or client standards. In my experience, IDS is best suited to checking attribution via the presence of specific property set definitions, property sets, and values.

Making our analogy back to current state of affairs, IDS is similar to current “look and feel” requirements for plans. You can use the authoring tool of your choice, but the PDF output must match the published example plans for fonts, abbreviations, and sheet ordering. I have focused on this analogy specifically because I remember a “look and feel” check as a specific part of our QC process and documentation from earlier in my career.

Specific Requirements for Project Information

Like the requirements listed above for a title sheet, digital deliverables should include similar project information:

• geospatial positioning
• contract number
• project identification / Des Number
• route name and reference posts / mile markers
• features crossed

All of these can be built in to consistent QC processes via IDS.

Model as Legal Document

There is an industry trend towards replacing traditional construction plans with the model data itself. Certain agencies have already piloted this approach with varying degrees of success. I’ve observed a fair amount of concern from designers about this approach, stating that they don’t feel comfortable certifying model data itself.

However, they are already doing this when certifying PDF plans. That is to say that they are not certifying the binary content of the files themselves, but rather the presentation of that binary content in a viewer such as Bluebeam Revu.

It’s not different with IFC - you are certifying the representation of the model content as presented in an acceptable viewer. In fact, the situation is even better with IFC because it is a human-readable plain text format. You can open it in any text viewer and review the data itself. Try doing that with a PDF!

Conclusion

2D plan set is to PDF as 3D model is to IFC.

Boiling things down to that analogy will go a long way towards calming fears about this new approach and ultimately getting practitioners on board and speeding overall adoption in the industry. This sets the stage for better cost control and schedule performance while also paving the way towards better as-built records that flow into asset management systems and set the stage for infrastructure digital twins.