As part of a joint venture, our team has been providing preliminary and final design and construction support services for the rehabilitation and/or replacement of approximately 1.5 miles of the Brooklyn–Queens Expressway (I-278) in Brooklyn, New York, since 2017. Twenty-one bridges exist along the length of the expressway, including a unique half-mile-long, triple-cantilever structure.
The project extends between Sands Street on the east and Atlantic Avenue on the west, including the entire Atlantic Avenue interchange in Brooklyn. It is situated among some of the densest urban environment in North America, with pervasive public and private geometric congestion. Its complexity contributes to tunnels, subway facilities; large sewers; privately owned, multistory structures, and extremely heavy traffic. Severely over-constrained, the New York City Department of Transportation (NYCDOT) has been looking for a building information modeling (BIM) solution.
As part of this project, NYCDOT requested that a full 3D BIM model be developed of the existing corridor to help optimize multidisciplinary coordination among the project team, improve accuracy in cost estimation, better assess constructability, act as a tool for clash detection, and develop the preliminary and final designs for the project. The 3D BIM model aids designers in understanding the effects of a proposed alternative, including impacts for each construction stage while streamlining the planning efforts of the final design and construction stages. The scope required the creation of a comprehensive model of the corridor’s structures, utilities, transit, and adjacent buildings, into which this section of the BQE is integrated. Until now, the level of understanding provided by this BIM would have been out of reach.
Work officially kicked off in early 2020. We led the BIM modeling, while our JV partner provided quality control reviews and civil and utility coordination with the JV’s surveyors. The JV used previously collected LIDAR scans of the corridor to create an as-built surface that the BIM model would use to tie the individual structural BIM models together at a level of accuracy not previously assembled along this corridor. Our team developed the 3D BIM models of 21 individual, unique structures along the BQE lacking almost any symmetry. Each model was created using available as-built plans from the 1950s, calibrating them to the current surfaces developed from the project LIDAR scans.
In parallel, our surveyors within the JV converted their 2D plans of the utilities and transit facilities into 3D models. Once all known aspects of the corridor were modeled, they were then assembled with the structural BIM models to evaluate and adjust the models to ensure they were properly integrated and matched the known underground layouts.
In May of 2021, the team completed the BIM and presented it to NYCDOT.
BIM modeling is more than just modeling in a particular program; it’s about understanding the real-world environment you’re creating virtually, then validating that what you understand in the real world is properly represented in the virtual environment. Delivering this task successfully was in large part the result of unwavering team commitment and coordination between many people. This was a rewarding experience for us, one which further refined our BIM capabilities and expanded our proficiency in the type of modeling that’s becoming more standard in designing the complex projects at which we excel.
Our hard-won work received acclaim from NYCDOT, and the skills and techniques used for this project are yet another example of how we remain on the leading edge.