Tag: Drones

A New Technology for Covered Bridge Inspections

Drone image of Kingsley Covered Bridge

The Unsung Beauty of Covered Bridges

Covered bridges, to me, were the quintessential structures of the 19th century, and to this day, can still inspire awe. These are bridges that were often built from trees cut locally, hand-hewn, brought to the site by livestock and assembled without modern machinery. When completed, you have a sort of house of cards; a wooden plank deck spanning a stream or raging river, walls reaching up from its sides containing many vertical and diagonal wooden members, a roof covering the expanse containing even more diagonal members, all held together with mortise and tenon joints and wooden pegs. This is a mongrel of bridge construction that has a beauty to it like no other, blending in with its surroundings as if it were always there, the backdrop for postcards, calendars and many personal moments shared between friends and loved ones. Sadly, most of these bridges have gone into the pages of history – neglected beyond repair, victims of mother nature, casualties of vandals, replaced with modern structures or simply forgotten. Those that still exist are revered and protected passionately by those who still believe in their relevance and their beauty. They do however require regular inspections and maintenance to ensure they can meet the needs of the communities they serve.

Those that still exist are revered and protected passionately by those who still believe in their relevance and their beauty. They do however require regular inspections and maintenance to ensure they can meet the needs of the communities they serve.

Inspections are Challenging for these Structures

Over the years, I have had the awesome opportunity to inspect many of these beautiful works of craftsmanship. These inspections are laborious in nature, requiring multiple days for a thorough inspection, getting covered in dirt and dust from crawling around the hard-to-reach spaces. It’s vital to know the size and condition of as many members as can be seen and reached, recording all that is found – dimensional losses, an array of structural deficiencies including but not limited to cracks, splits, checks, insect infestation and rot to name a few. The tape measure, extension ladder, headlamp and digital camera are tools of the trade. But what about inspecting the places that are more difficult or impossible to get to because of the length and height of these structures or the geography they span?  Simply put, you get what you can, as good as you can, and the rest is filled in with existing plans and many, many digital photos. The camera is your best friend when inspecting and is an invaluable resource. But even so, photos can be deceiving – awkward angles, poor lighting and size distortion, cause confusion as to what is truly being captured. As for inspecting floor systems, getting underneath is the only way to go, either by rigging, rope climbing or even by boat if the height above the water makes it feasible.

When the Standard Inspection Options Aren’t Adequate

Recently I traveled to Clarendon, Vermont with Josif Bicja, PE to inspect the Kingsley Covered Bridge for a scoping report to determine the feasibility of multiple rehabilitation options. This is an historic 119-foot-long, single span, town lattice bridge spanning the Mill River flowing 35 feet below. The Kingsley Covered Bridge poses the same issues as any other covered bridge inspection, but in addition, because of the height above the stream, it makes it difficult if not impossible to get a good visual of the floor system and siding. A rigging company could have been hired to provide access to inspect the floor system through the use of bridge trackers or bucket boats which will get you up close to get that good visual, or the bridge could have been climbed, but these options are not economically feasible for a scoping study. The options you are left with is to don a pair of waders, carefully walk out into the water with your clipboard and camera and capture what you can. If the water is not passable, you stand on the shore and do your best to get the information you need.

There is a better way. The drone. Those sci-fi looking machines, with their distinguishable propeller sound that are used widely in law enforcement, the military and with private enthusiasts alike, have been making their way into other useful applications. Over the past few years, engineering companies like Hoyle, Tanner have seen the value of drones for public relations documents, project marketing, 3D visualizations, traffic studies, and now bridge inspections. The height of this bridge over the Mill River made it a perfect candidate to fly a drone and test its capabilities in this capacity. Drones have safety features that will not allow them to fly close to aerial obstructions, like trees and overhead utilities, or fly in strong winds such as updrafts under a bridge, which are both prevalent at this site. The safety features would have to be turned off for the drone to perform its inspection well, which meant that the steady hand of an experienced pilot would be essential.

For the underside of the bridge, it flew a few feet from the structure providing the ability to clearly see the members that make up the floor framing, including joint locations and condition. Then the drone was flown along the sides of the bridge and along the roofline, capturing a similar up-close visual of the vertical siding and metal roof conditions that we normally would not have been able to see.

Patrick Sharrow, AAE from our Burlington, Vermont office drove down and met us on-site on the morning of our second day inspecting the bridge. It took Patrick just a few moments to familiarize himself with the structure and geography of the site, understand what we needed the drone to capture and determine the best launching spots for the drone. Looking at the handheld monitor, Josif was able to give instructions as to where he needed the drone to fly,  while I acted as spotter to make sure the drone kept a safe distance from any aerial obstructions and Patrick executed the flight. For the underside of the bridge, it flew a few feet from the structure providing the ability to clearly see the members that make up the floor framing, including joint locations and condition. Then the drone was flown along the sides of the bridge and along the roofline, capturing a similar up-close visual of the vertical siding and metal roof conditions that we normally would not have been able to see. The videos captured of these hard-to-get-to portions of this bridge will allow for better recommendations for the multiple rehabilitation options, leading to more accurate costs for the client. We then took the drone to a higher elevation and flew a few hundred feet upstream down towards the bridge, giving a bird’s eye view of Mill Stream. Patrick flew it at different elevations and angles capturing fantastic footage of the morphology of the stream and a greater scope of how this bridge is situated on the site. Portions of these videos could be used in public information meetings to help educate the public and as tools for Hoyle, Tanner.

Day-to-Day Needs of the Community Combined with Aesthetic Nostalgia

In less than an hour, we were able to gather more information about this structure than we would have been able to because of the site restrictions this bridge poses. The best part is that all players in the game benefit from this. The design team will have the ability to make more accurate rehabilitation recommendations. The client will have the advantage of receiving more accurate cost estimates for each rehabilitation option. The public will receive the best rehabilitated structure option, marrying together the day-to-day needs of the community and the aesthetic nostalgia it provides to all.

How Hoyle, Tanner is Saving Time and Money with Drone Flights

Clearing the air! This is what our small Unmanned Aircraft Systems (sUAS – commonly referred to as drones), operators Evan McDougal, CM and Patrick Sharrow, AAE are incorporating into airspace analysis. Evan and Patrick are just two of Hoyle, Tanner’s professional Part 107 remote pilots who are utilizing photogrammetry and advanced autonomous sUAS technology to analyze and access airspace obstructions. With recent media highlighting the challenges of integrating sUAS operations into the National Airspace System, it is an exciting time to focus on the safer, less expensive, and expedient capabilities that these vehicles make possible.

Many organizations, both private and government, are interested in what these small flying sensor system platforms can do. For instance, many state aeronautics agencies that oversee the safety and operation of multiple airports can spend weeks with multiple survey teams and inspectors traveling from airport to airport assessing tree canopy and surrounding buildings – all in an effort to determine if there are obstructions to FAA approach and departure surfaces and pilots utilizing the runway.

In contrast, a drone can be flown by a trained and qualified pilot to collect accurate obstruction data. The three-dimensional results can show the entire area in many formats in a fraction of the time and cost it would take a ground survey crew or aerial survey.

Hoyle, Tanner is passionate about increasing safety and efficiency in aviation. During the September 2018 National Association of State Aviation Officials (NASAO) Annual conference in Oklahoma, Evan McDougal demonstrated his enthusiasm for the emerging technology and the airspace analysis applications we have developed.

Evan showed interested State Aeronautics Department Representatives how they could benefit using sUAS systems for obstruction analysis. Bryan Budds, Transport and Safety Section Manager at the Michigan Department of Transportation (MDOT), was quick to recognize the benefits of this capability and the opportunity to advance the MDOT existing drone program. He arranged for Hoyle, Tanner to spend three days training DOT employees on how to collect accurate obstruction data using drones as well as process it into meaningful deliverables.

The information gathered in the sUAS flights is used to create detailed 3D models of the airport including trees, pavement condition, ground contour elevations, and surrounding land development. Once collected, the data can be used to graphically depict airspace approach corridors that are not able to be seen with the naked eye. Obstructions are clearly shown protruding into protected airspace making it much easier for the airport and responsible landowners to agree on obstruction removal alternatives.

With the proper coordination of sUAS data collection and software processing systems, “clearing the air” can be done economically, accurately, and efficiently. The exciting reality of the sUAS market is that the sky is the limit! Hoyle, Tanner is committed to continually evolving and developing new opportunities to increase safety and efficiency in aviation moving into the future.

Curious about how you could use drones on your next project? Contact our experts Patrick Sharrow, AAE, psharrow@hoyletanner.com or Evan McDougal, CM emcdougal@hoyletanner.com

Drones: Enhancing Safety & Expanding the Aviation Community

Flying Drone

Small Unmanned Aerial Systems (sUAS), or as they are more commonly known as, drones, are changing inspection and construction methods and expanding the aviation community. Drones are the fastest growing segment of aviation. Currently, they are being used by public safety officials, realtors, farmers, engineers and of course by aviation hobbyists across the country. Depending on your perspective, drones are an emerging aerial solution or an impending aerial disaster just waiting to happen.

A major concern of the FAA regulators are the hazards of drones and manned aircraft in the same airspace. On December 12, 2017, Barrie Barber from Cox Newspapers published “FAA: Drones more deadly than birds.” In the article, Barber writes the “FAA has guidelines for building aircraft to withstand bird strikes of a certain weight, but tougher requirements do not exist specifically for drone collisions.” While it might seem obvious that a drone could do some damage, the impact damage of a bird and drone of similar weight are significantly different.

“The research found heavier, stiffer components, such as a drone motor, battery or a camera, could cause more structural damage to an aircraft than birds of the same weight and size,” said Kiran D’Souza, an Ohio State University assistant professor of mechanical and aerospace engineering.

While pilots have reported many drone sightings to the FAA, the FAA reports only one incident in the United States of a drone striking a Military Black Hawk helicopter in October 2017. In fact, the Unmanned Aircraft Safety Team (UAST) Drone Sightings Working Group released a new report on the Federal Aviation Administration’s (FAA) 3,714 drone sightings reports collected by flight crews, air traffic controllers and citizens from November 2015 to March 2017. The report found that only a small percentage of drone reports pose a safety risk, while the vast majority are simply sightings.

Despite growing pains employing drones, many industries and public agencies are adding them as tools and developing workflows to effectively employ them. Stamford Connecticut police Sgt. Andrew Gallagher did an interview for the Fairfield Citizen and explained how his police department has used drones to document and analyze accident scenes, conduct searches and track suspects. Fire Departments are now using drones with infrared cameras to quickly view fire scenes from different angles to best direct the crew response.

“I have stood on more fire trucks than most firemen looking for an overhead shot. We are always looking for something to stand on,” Gallagher says in the article. Drones provide different aerial shots that can give intelligence about where a person or accident could be – in real time, without putting lives in danger.

In addition to first responder use and Amazon’s idea to deliver packages via the airways, drones have provided opportunities in the professional planning and engineering field.

Evan McDougal, Airport Planning Manager with Hoyle, Tanner & Associates, Inc., is an FAA-certified manned aircraft pilot as well as an FAA Section 107 Remote Pilot. McDougal says that drones are an inexpensive data collection solution when airports have tree obstructions that have grown into the runway approach surfaces. These obstructions can limit the ability of pilots to use instrument approaches at night and in some cases the obstructions cause the FAA to increase the cloud ceiling or visibility requirements or limit how low a pilot can descend on approach to a runway. Many runway ends in Maine are not available at night due to known tree obstructions.

McDougal believes drones could be part of the solution.

Drones can quickly capture highly accurate aerial imagery that can be analyzed using photogrammetry software to identify the boundaries of tree canopy penetrating the imaginary (but very real) instrument or visual approach surface. An example of the typical results can be seen in this effort. https://www.dropbox.com/s/iw4vabrcszm5w1s/B21_17%20End%20P4D%20Ani.mp4?dl=0

How it works: while following an autonomous flight plan the drone takes hundreds of georeferenced high definition photos. Photogrammetry software accurately stitches these photos together by matching thousands of key points within adjacent photos. This creates a full orthomosaic of the entire surveyed area and produces a very accurate three-dimensional model or point cloud that can be measured and examined thereby allowing engineers and airport owners to see exactly where runway obstructions exist.

This is but one use for a drone at airports. The technology is evolving very quickly and is limited only by our imagination.