Collins Engineers was tasked with inspecting and designing the rehabilitation of the iconic Stone Arch Bridge in Minneapolis. The 22-span masonry arch bridge opened in 1883 and is 2,100 feet long. Originally built as part of the Great Northern Railroad, it became a pedestrian bridge in the 1980s and is the most historically significant bridge in Minnesota. With its age and size, the team faced challenges when developing repair plans that traditional data collection could not accommodate. The bridge is in a busy urban environment, making access to the bridge difficult. They used reality modeling previously, but it lacked the quality required for inspecting and modeling complex structures, especially large masonry bridges. To collect sufficient data and accurately model the bridge, they needed an integrated survey, modeling, and inspection solution.

Collins Engineers selected ContextCapture to generate a high-fidelity 3D model from over 13,000 images, improving quantity and quality of data. By creating a digital twin, the team could record field inspection notes directly in the model, removing the need to sketch or describe defect locations for improved accuracy. Using iTwin applications facilitated real-time model access, saving 20% of field time. The solution is expected to save 10% to 15% in construction costs due to improved project and bid data. Because of the high level of detail in the digital twin, they will use it throughout the bridge’s lifecycle for future planning and maintenance decisions. The digital twin was so accurate that Microsoft used it as part of their keynote address at their Ignite conference.