Tappan Zee Hudson River Crossing: The New
    New York Bridge

    New York, United States

Project Summary

HDR was awarded the contract to design and build the new New York Bridge – which will replace the traffic-jammed Tappan Zee Bridge – on an aggressive schedule. In addition to crossing the Hudson River at one of its widest points, the design included twin tower cable-stayed main spans with 1,200-foot center spans, four traffic lanes, shoulders and emergency lanes, electronic tolling facilities, a shared-use path, and space for future mass transit. The owners also required an as-designed model and a complete, as-constructed database of assets derived from and tied to a 3D model.   

Using BIM processes and Bentley software, designers created bridge components with custom bridge metadata assigned to them. Structural members comprised of 3D meshes were imported into a geospatially correct MicroStation file. The additional bridge properties were added with i-model Transformer. To integrate as-constructed information into as-built 3D models, comprehensible unique identifiers were created. Designers used them to identify each part of the bridge within the construction management software.   

HDR worked with Bentley and other software providers to integrate Bentley’s design models and the resultant i-models with the construction management software ELVIS. This integration facilitated the project requirement of linking the as-designed model to the as-constructed model and allowed HDR to deliver to its clients the final 3D models with all relevant data for maintenance and operations.

Parametric bridge elements were created using AECOsim Building Designer and key structural members were created and designed within RM Bridge. The teams also used MicroStation, InRoads, InRoads Storm & Sanitary, LEAP RC-PIER, GEOPAK, Bentley Rebar, Bentley Map, Bentley Descartes, and i-model Transformer. ProjectWise provided project collaboration, allowing HDR and sub-consultants to quickly find, share, and interact with appropriately managed, interrelated engineering content and meet aggressive deadlines.
  • HDR leveraged Bentley BIM advancements to provide a more accurate design and meet an aggressive schedule.
  • Based on the final design, the new bridge will have a 100-year service life. Owners will be able to refer to an accurate, as-built 3D design model to optimize maintenance and service activities.
  • HDR employed Bentley innovations such as hybrid modeling, i-models, and point-cloud streaming to overcome challenges and deliver the right design, on time.
User Quote:
  • “Bentley and its products were fundamental to being able to collaborate on such a huge project with over 30 subs scattered across North America.”

    Robert A. McKenna Engineering BIM Lead HDR Pittsburgh