Reimagining bridge inspections through the lens of digital twins

By Meg Davis, Industry Marketing Director, Roads and Bridges at Bentley Systems

A key part of any transportation network are bridges, and maintaining these infrastructure assets is important to ensure public safety. Inspections that gauge the structural integrity of bridges as well as information gathered during these inspections give bridge owners and engineers the necessary data to plan for the maintenance, rehabilitation, and bridge replacement.

The problem for bridge owners is that traditional visual inspections are labor intensive, can require expensive equipment, may present safety risks, and can be inaccurate and error prone, depending on accessibility and reporting methods. Collecting data can be difficult and when inspectors lack a detailed understanding of historical change that can affect the time and cost of inspection activities, as well as adversely impact the movement of the general public. And, in some countries, new regulatory compliance rules and associated reporting requirements add another layer of complexity.

Some of Bentley’s most innovative users are reimagining inspections through the lens of digital twins. A digital twin is a digital representation of a physical asset, process or system, as well as the engineering information that allows us to understand and model its performance. A digital twin can combine data from continuous surveys, photogrammetry, LiDAR, and sensors, and track changes to assets on a timeline, enabling owners to view the digital representation of the infrastructure asset and related real-world conditions over time. As DOTs and agencies are being pressed to show the most effective use of their limited funding, taking advantage of digital twins can provide for safer, less expensive, more timely and accurate inspections. Digital twins allow owners to track historical changes and understand information such as the exact size of cracking, corrosion, or section loss, rather than trying to determine this information by looking at pictures taken over time.

We have seen agencies such as Minnesota DOT use drones to assist with their inspections and achieve savings of as much as 40% with these methods. Because bridges have such a long lifecycle, often up to 75 to 100 years, it is important to track change to the structures over time. MNDOT found that by deploying drones and having a digital twin, they were able to see the change over time and have a holistic view of the bridge, including seeing past inspections laid on top of the current data, which can improve efficiency and help predict the future.

There is great opportunity for agencies to use UAVs and drones to complement and augment standard and in-field inspections. The data from these inspections can be reviewed quickly and easily in the office. By reviewing time-lapse comparison of detailed changes, annotating specific areas of concern, and noting anything that needs to be specifically reviewed in the field. Field crews can see all the inspector notes right on the structure, which is more visual, more accurate, and more efficient. All of this is geared toward saving costs, avoiding risks, and reducing the time required for inspections.

Digital twins help you take advantage of innovative ideas, such as the concept of remote inspections. Through a digital twin of an asset, along with immersive inspection capabilities in Microsoft HoloLens, inspectors can conduct significant parts of the inspection while in the office, reducing the time required in the field, which makes the overall inspection quicker, more efficient, safer, and less costly. A digital twin provides flexibility as you can conduct more in-depth inspections without having to schedule expensive equipment and labor for that purpose. Applying digital twins over many large, complex, or signature bridges can lead to significant savings, while increasing safety and providing richer visualization is the ultimate goal.

One of the biggest advancements we see is a reality mesh, the visualization for a digital twin that gives yet another dimension to our understanding of the infrastructure and surrounding topography. As agencies use drones to assist with their inspections, the photos or videos and data they capture can be used to produce a high-resolution reality mesh of the bridge. And, when combined with other relevant data, this provides a great digital twin representation, whether on or off the network, above ground or below ground. Recording those reality meshes over time can provide better insights into changes within the structures. Using reality meshes for inspections can significantly decrease the amount of time inspectors have to be on and around structures in the field.

Utilizing digital twins and technology including drones and UAVs to collect, process, store, and analyze large amounts of data can reduce time and costs while increasing quality of inspections. The technology can improve safety for inspectors and the public at large and help preserve bridge infrastructure into the future.