By Bart Treece, Director of the Mobility Innovation Center
Bridges are amazing! We depend on them to help us safely travel from point A to B, and to keep these structures in good shape, we depend on people who do maintenance, inspections, and make decisions on when to replace the various parts that wear out over time. They collect information, often by visual inspections on a routine basis or after an incident (think: earthquake or potential damage is seen) to decide when rehab and replacement work is required. How much better would it be if there were more in-depth data that could forecast future needs?
The way critical infrastructure is managed and maintained could be changing with new digital tools and applications that transmit stresses and strains overtime to understand the maintenance, operations and preservation needs that a bridge might have. Our I-90 Digital Twin Technology Evaluation aims to figure how sensors and digital twins can be potentially useful for this purpose, using one of the most complex bridges in the world.
Let me take you back to what our project is. Our goal is to evaluate if a digital twin can be used for operations, maintenance, and asset management, with the I-90 Homer Hadley floating bridge between Mercer Island and Seattle as our test case. A digital twin is a virtual simulation that incorporates data to help make decisions. We are using internet of things (IoT) sensor placed in specific locations on the bridge to measure stress on the anchor cables, and alignment of the structure that is adjusted twice a year with the water level on Lake Washington.
Digital twins have been used in different industries, like manufacturing, and even in space exploration, but this practice hasn’t been applied to a bridge for this purpose. If successful, it could be a new method that makes the most of technology to evaluate replacement cycles of bridge parts, potentially saving money if they can be deferred thanks in part to better data. Think of this as an extra sets of eyes for the people who maintain critical infrastructure.
Pulling partners together
There are some crucial elements in a Mobility Innovation Center project. It needs the right mix of partners who have something to offer and a good reason to be involved. In other words, some skin in the game and committed to a shared win. The idea of the digital twin came from several conversations, one with Microsoft’s Critical Infrastructure group that wanted to show how cloud computing can be used for managing transportation assets, like bridges. Another came from T-Mobile who sees that a 5G network can be used to connect sensors for smarter cities. We rely on Bentley Systems for their software iTwin platform to view the digital twin, and WSP USA for their expertise and prior building image model (BIM) of the I-90 Homer Hadley floating bridge. Semtech is providing wireless routers and technical assistance to ensure the sensor data transmits to the Azure IoT hub. We cannot do this without these partners.
The right academic personnel are critical. Travis Thonstad from the Department of Civil and Environmental Engineering has a unique history with the bridge and his research evaluates various components to understand their structural limits. Carrie Sturts Dossick, professor of Construction Management, brings her expertise in cyber security and digital twins for this project. Our students, Ori Borjigin who is working on his PhD with a focus on cybersecurity, and Timothy Bernard, who is pursuing his master’s in civil engineering, have been essential in the development of the IoT hub and ensuring the sensors are transmitting useful data ahead of deployment on the physical structure.
This is a public-private partnership with funding from the Federal Highway Administration, both from the Advanced Bridge Construction/Innovative Bridge Technologies University Transportation Consortium, and the State Transportation Innovation Council (STIC), and from local businesses. We also couldn’t have done this without the support and collaboration of the Washington State Department of Transportation who are interested in understand how this approach could be useful for asset management, maintenance and operations of one of the most complicated bridges in the world.
What’s next?
With equipment testing nearly complete, we plan to deploy sensors on the bridge this fall for a year of data collection and monitoring. The findings will be shared with WSDOT and all state departments of transportation through a workshop and a report.
We have learned so much in the ramp up that are immediately useful for a digital-based transportation asset, such as data management and ensuring the appropriate cybersecurity measures are in place. Once we begin receiving information from the bridge, the movement of vehicles and trains, we will a better insight into how these new tools can possibly help us manage the infrastructure of tomorrow.