A Million Small Connections

Designing the New NY Bridge


  • Tappan Zee Constructors, LLC (TZC) is the design-builder of the $4 billion, eight-lane New NY Bridge (also called the Governor Mario M. Cuomo Bridge) to replace the existing Tappan Zee Bridge.
  • HDR is TZC’s lead designer for the New NY Bridge (NNYB) project.
  • The New York State Thruway Authority (NYSTA) required a 3D model that hyperlinked to project documentation.
  • Project modeling will contain over one million estimated connections; over 400,000 connections to date.
  • The solution involved a suite of software including InEight, Bentley and Bluebeam

Connor Christian wasn’t supposed to be working on the NNYB. Based in Omaha, Christian, who is Director of Digital Implementation at HDR, was visiting the offices of TZC (the consortium of design-builders constructing the NNYB) regarding an unrelated transportation project. One day, HDR’s Project Director, Jeff Han, burst through the door and asked him, “You’re the new BIM guy, right?” Christian was pulled into a meeting about the twin-span crossing, and he barely had time to look back.

New York’s Tappan Zee Bridge first opened to traffic in 1955. Built during a time of material shortages due to the Korean War, it had a design service life of 50 years. After more than six decades of service, the bridge finally saw its last vehicle in October of this year. Meanwhile, the Governor Mario M. Cuomo Bridge, a $4 billion, eight-lane infrastructure magnum opus that will see over 51 million vehicles a year, is open for business while construction on the eastbound bridge is ongoing. When it fully opens to traffic next year, the new crossing will also feature shoulders, space for emergency responders and dedicated bus lanes. There will also be a shared-use path for bicycles and pedestrians.

BIM Deliverables

As lead designer of the NNYB, part of HDR’s project deliverables to TZC, and ultimately to NYSTA, include a 3D model linked to project documentation. This project requirement was forward thinking at the time that the RFP was written about five years ago, and it was far from standard practice for an owner to demand a BIM deliverable.

Fast-forward five years, and digital design tools had advanced greatly. Christian needed to figure out a way to electronically link 3D model design elements to their corresponding documentation. There were over a million elements that would need to be hyperlinked. Manual input was not an option if the project was going to be completed on schedule: “If I made connections like that, and I made one connection every minute and that’s all I did all year long, it would take me over 11 years,” says Christian.

Theoretically, it was possible. But as with most complicated things in life, theory and practice are not always necessary best friends.

Collect, Organize, Connect

By design, each element on the project’s 3D models carried a minimal amount of data—what objects were, and their location, such as, “I’m girder number five on the eastbound side, on unit number seven, span 26,” explains Christian. That basic information needed to connect to a whole lot more, such as construction, installation and maintenance detail, construction photos and shop drawings. Another challenge was partitioning this data due to security concerns, so that only individuals with proper clearance could inspect a particular element. Additionally, each element needed to contain its inspection number, as mandated by the American Association of State Highway and Transportation Officials.

A suite of design and project management software had been used over the course of the project, including InEight, Bluebeam Revu, ProjectWise, Revit and AECOsim. After several weeks of brainstorming, Christian and his team were able to survey what they did have—lots of disorganized data and files that weren’t named using standardized conventions—and find a way forward. At that point, all the information was properly organized in ProjectWise, an engineering collaboration software. Then, the team used InEight to create a hyperlink prototype, which the software extrapolated using preset parameters indicated by the naming convention, to produce an entire batch of hyperlinks.

Once all the data had been integrated and organized, and the correct parameters optimized, Christian said, “The hyperlinks created themselves.” He calls this strategy “collect, organize, connect.” Now, Christian and HDR are teaching NYSTA how to handle the data management themselves, so they can better track maintenance and performance issues and so that the biggest new infrastructure project doesn’t have to take an unscheduled break any time soon.

See how Bluebeam Revu helps engineers keep their data organized.