Bridging the Mississippi with Bridge Information Modeling

The Third Avenue Bridge in Minneapolis is an iconic early 1900s road crossing over the Mississippi River. It is one of 24 bridges of prominent historic and architectural significance that the Minnesota Department of Transportation (MnDOT) has selected for long-term preservation.

At 102 years old, the bridge was showing signs of concrete distress, concrete cracking, and corrosion damage. As such, in 2019 a restoration project was initiated to repair the arches and re-deck the bridge to extend its design life by 50 years while also improving its safety and accessibility features and enhancing its historic and visual features.

The project team used Bridge Information Modeling (BrIM) to ensure successful restoration. BrIM is an application of building information modeling (BIM) used for the design, construction and maintenance of bridges that allows users to interrogate the design of a bridge in 3D to help better understand how different elements integrate. It is particularly useful for translating complex 2D designs into intelligible 3D imagery.

In the case of Third Avenue Bridge, the original construction plans no longer reflected reality. BrIM was instrumental in bringing disparate datasets together that, once combined, filled project data gaps and presented a new perspective on the project’s construction requirements.

One major constraint of the project execution was that almost all the project’s construction works needed to be implemented from the existing superstructure, with careful consideration given to the bridge’s structural integrity and the impact of fluctuating loads as concrete sections were removed and repaired.

The movement and location of construction vehicles, as well as materials arriving and being removed from the site, needed to be carefully sequenced to maintain the bridge’s structural integrity. Using BrIM, the project’s engineers simulated various restoration scenarios to resolve conflicts and arrive at the most effective schedule. Being able to track arch movement in relation to the weather and load on the bridge meant the project team was able to adapt the construction method and remain one step ahead on safety.

Given the project’s complexity, visuals were essential to aid those not familiar with the project's details. A 3D BrIM model enhanced visualization, which improved step-by-step comprehension of the restoration as the work moved between spans.

The use of BrIM created a single source of truth across the project for the construction’s stakeholders. With stakeholders working from one centralized project source, collaboration and communication were more effective and led to better project outcomes. As a result, there were few instances of rework or schedule delays due to unmitigated risk, which was an important key performance indicator for the asset owner.

BrIM is now widely used by COWI on projects across Europe and India, and has proven to be highly effective at enhancing communication and collaboration and improving project outcomes, with similar results replicated at the Fargo Morehead Bridge in North Dakota and the Houston Ship Channel Bridge in Texas. With hundreds of complex capital infrastructure projects underway in North America each year, the opportunity to benefit from BrIM is huge.