MNDOT Utilizes Virtual Bridge Inspections


To restore a 19th-century bridge in Minneapolis, officials from Collins Engineers are working with the Minnesota Department of Transportation on incorporating Microsoft HoloLens headsets with software from Bentley Systems.

The use of the technology is expected to speed up the inspection process on the James J. Hill Stone Arch Bridge while the project works through the design phase.

“The HoloLens gives us that sense of scale we only get in the field,” said Barritt Lovelace, Director of UAS, AI and Reality Modeling for Collins Engineers. “When looking at a computer screen you can zoom in, but it doesn’t feel like the bridge is in the field. With HoloLens it is different.”

Virtual Inspections

According to reports, the HoloLens headsets work by incorporating high-resolution drone photographs of the structure and piecing them together in a sort of “reality mesh” 3D model comprised of millions of polygons. The result creates what Bentley describes as a mixed-reality workflow, which aims to combine inspection photographs with physically being onsite, without actually having to be onsite.

The technology is currently part of Bentley’s AssetWise system, and the reality meshes are linked up to the digital twins maintained of existing structures.

Dan Vogen, Vice President, Road and Rail Asset Management at Bentley Systems reports that the technology offers more information traditionally produced in regular 3D models and is better able to convey the structure’s texture and current conditions.

While the reality mesh can be viewed on a computer or tablet, in using the cloud-connected HoloLens, users can view the bridge at a zoomed-out tabletop view of at a 1:1 scale, allowing engineers to see portions of the structure up close in high resolution. During this type of virtual inspection, the engineer can add annotations, perform measurements, and highlight potential problem areas.

Collins Engineers is working with Minnesota DOT on the restoration of the James J. Hill Stone Arch Bridge in...

Posted by Bentley Systems on Sunday, March 28, 2021

“To me, the most impactful thing of putting your inspection notes on a model compared to traditional notes is you no longer have to describe where the defect is,” said Lovelace. “It definitely speeds up the process and allows us to give MNDOT better data.”

Although the collaboration isn’t seeking to replace in-person inspections, Lovelace also noted that the technology has reduced the number of trips needed to inspect the bridge and allowed engineers from other cities to add their input as well without having to travel.

“We don’t have the budget to send everybody we want out there all the time,” he said. “But if someone in Chicago wants to help on the design of the cofferdams, they can look in HoloLens at the model.”

Bentley is currently exploring HoloLens as an inspection tool for other difficult-to-access structures, including communication towers and electrical utility transmission towers.

While MNDOT has policies in place governing drone flights for bridge inspections that comply with Federal Aviation Administration regulations, Jennifer L. Wells, MNDOT state bridge inspection engineer, predicts that a version of the workflow could eventually become a standard practice for bridge inspections in the state.

“We've seen some scope creep when it's time to close a bridge, because local agencies are not getting the access they need ahead of time [to inspect the bridge],” she said. In utilizing the new technology, local municipalities could save time and money in getting through inspection work.

Infrastructure Inspection Technology

In November, the FAA launched a new BEYOND program, which is slated to continue the partnerships and progress it made under a three-year Unmanned Aircraft System Integration Pilot Program and would continue to address remaining challenges currently keeping unmanned aircraft systems from being fully integrated into the national airspace system.

Launched in 2017, the UAS IPP program has brought state, local, and tribal governments together with private sector entities, such as UAS operators or manufacturers, to test and evaluate the integration of civil and public drone operations.

According to reports, the program was created to assist the U.S. Department of Transportation and the FAA develop rules supporting more complex low-altitude operations by:

  • Identifying ways to balance local and national interests related to drone integration;
  • Improving communications with local, state and tribal jurisdictions;
  • Addressing security and privacy risks; and
  • Accelerating the approval of operations that currently require special authorizations.

Over the course of the program, IPP Lead Participants evaluated a host of operational concepts, including night operations, flights over people and beyond the pilot's line of sight, package delivery, detect-and-avoid technologies and the reliability and security of data links between pilot and aircraft.

The remaining challenges faced in incorporating UAS into the airspace system include:

  • Beyond Visual Line of Sight (BVLOS) operations that are repeatable, scalable and economically viable with specific emphasis on infrastructure inspection, public operations and small package delivery;
  • Leveraging industry operations to better analyze and quantify the societal and economic benefits of UAS operations; and
  • Focusing on community engagement efforts to collect, analyze and address community concerns.

Additionally, the new program plans to focus on operating under established rules rather than waivers, collecting data to develop performance-based standards, collecting and addressing community feedback and understanding the societal and community benefits, and to streamline the approval processes for UAS integration.

That same month, founders of Niricson, a Victoria, British Columbia-based technology company, reported that their drones could soon be used for maintaining infrastructure across Canada, the United States and around the globe.

According to the Journal of Commerce, the drone technology uses visual, acoustical and infrared heat sensing to inspect what’s underneath an infrastructure’s concrete surface. The combination of technology can reportedly detect cracks, voids or other issues by flying around the structure and collecting information using its onboard acoustic recorder, optical camera and infrared camera.

Once the data is collected, it is then immediately analyzed using Niricson’s software—developed three years ago by Rathod and his PhD supervisor Rishs Gupta—which can further indicate the width, length, depth and overall significance of the defects and, if necessary, can start taking actions to repair them.

However, beyond inspections, the system can also be used to track damage over time so civil engineers can plan preventive maintenance.

Since launching the company with Aki Tomita, Rathod reports that the company has 11 people on the team and recently completed funding efforts, which raised $800,000 to continue developing drone technology to open new markets.

Niricson adds that besides working with BC Hydro, it has since signed contracts with other utility companies in the U.S. and Canada and is also trying to arrange partnerships with engineering consulting firms.

Apart from the industrial side of things, earlier this month, the New York City Department of Buildings announced that it had begun piloting a new Remote Video Inspections program that plans to replace in-person visits for some construction inspections.

The program, which began March 19, lasts for six weeks and will end April 30. Reportedly, the voluntary program will occur for some construction site in Staten Island and Brooklyn. If at the end of the pilot period the program is deemed a success, the DOB will expand the procedure to the rest of the city.


Tagged categories: Bridges; Bridges; Department of Transportation (DOT); drone; Drones; Engineers; Infrastructure; Inspection; Inspection equipment; NA; North America; Program/Project Management; Technology; Tools & Equipment

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