Minnesota in the Upper Midwest of the United States has several state nicknames.  It is called The Gopher State, The Agate State, The North Star State, The True Star State, The State of Hockey, and most commonly The Land of 10,000 Lakes.  With so many lakes crossing through Minnesota there is an equally large number of bridges throughout the state.  There are close to 20,000 bridges, with 830 of those bridges being deemed structurally unsound.  In 2007 the 35W Bridge in downtown Minneapolis crumbled into the Mississippi River during bumper to bumper rush hour traffic.  This incident took the lives of 13 people and injured another 145, some severely.

The tragedy served as a wake up call for Departments of Transportation all over the country to better invest in bridge inspection and maintenance. Minnesota is still trying to tackle the massive job of repairing it’s numerous bridges.  It is a high risk, time consuming, traffic inducing, expensive undertaking.  The traditional means of inspecting bridges requires police to shut off traffic to the area in need of inspection causing logistical traffic nightmares for commuters.  Then a large work crew is needed to oversee the inspection.  This is done either through the dangerous method of literally hanging by a rope off the side of a bridge or using a Snooper truck.  A Snooper is a heavy duty truck with a long extendable arm that runs close to $1 million.  Either method is time consuming, costly, and puts human life at risk.  This is why the MnDOT (Minnesota Department of Transportation) began researching alternate methods for bridge inspections.

In 2015 MnDOT began experimenting with drone technology to complete bridge inspections.  After several phases of research they found the program to be highly successful.  The first and second phases of this operation required the MnDOT to closely analyze the rules and regulations for using drones in an urban environment as well as the financial costs of such a program.  The final third phase focused on how the drones will work in the actual environment through actual trials.  A report put out by the MnDOT states, “Researchers continued to advance expertise for using UAS to inspect Minnesota bridges. Using UAS can reduce inspection costs by up to 40 percent compared to using traditional methods. UAS inspections also require fewer crew members, shorten or eliminate traffic closures, and improve safety for crews and the public.”

The drone being used for these inspections is the Flyability Elios by a Swiss company pioneering how drones are designed for indoor flight and tight spaces.  According to Flyability’s website, the Elios is “the first collision-tolerant drone, designed for the inspection and exploration of the most inaccessible places. Allowing for the first time to fly in complex, cluttered or indoor spaces, Elios unleashes the potential of UAVs in numerous applications where their use was previously too dangerous or simply impossible.”  It is a small drone that is entirely surrounded by a shock absorbent frame.  This allows the drone to fit into tight hard to reach spaces without worrying about the risk of mission failure from collision in such confined space.  With it’s onboard lighting and HD camera provide live video feedback, the Elios has been allowing bridge inspectors to safely see areas of bridges they couldn’t before.

The MnDOT is leading the way in how bridges can be efficiently inspected to determine exactly what measures are needed to ensure a tragedy like the 35W Bridge never happens again.  In the official report on the MnDOT’s findings by Barritt Lovelace and Jennifer Wells they state, “Bridges are a key part of our transportation system and maintaining this infrastructure is important to ensure the safety of the traveling public and to effectively manage these valuable assets. Safety inspections not only ensure the structural integrity of a bridge but provide valuable data to decision makers. The Minnesota Department of Transportation and Collins Engineers, Inc. has completed this third phase of research focused on utilizing drones as a tool for improving the quality of bridge inspections.

Our world is being transformed by technology including drones that can collect, process, store, and analyze large amounts of data and this research is applying the same transformative concepts and technology to improve bridge inspection outcomes. Sarah Sondag is a metro bridge inspection engineer with MnDOT.  She is thrilled with the results they are finding with the use of drones to inspect bridges.  She points out that in no way will these drones take away or replace human jobs.  Instead they are being used as a tool for inspectors to more efficiently and safely do their jobs.  So far the only downside Mr. Lovelace (jokingly) saw was that the inspectors need to find another way to get in their daily exercise.