Drones hover over C- infrastructure


Drone-based civil infrastructure inspections

Aging infrastructure is a worldwide challenge, and the United States is no exception. The 2021 report card from the American Society for Civil Engineering (ASCE) gave America’s infrastructure a C- for condition and performance. This poor grade is the result of an infrastructure that continues to deteriorate with age, increased use, and insufficient investment. In addition, protecting infrastructure under such extreme events as hurricanes, floods and earthquakes has become increasingly important.

Since the beginning of the COVID-19 pandemic, surveying infrastructure safety with remote-sensing technologies has become more prevalent. This approach is beginning to replace the traditional practice of manual inspection by specially trained professionals, which often is costly and inefficient, and sometimes is risky — making it not ideal for the huge amount of U.S. infrastructure.

We really need to introduce more remote-sensing and cutting-edge technologies like unmanned aerial vehicles (UAVs) into infrastructure inspection. UAVs equipped and integrated with different types of sensors offer many advantages over traditional technologies, such as easy accessibility, remote controlling, and high accuracy and efficiency. More importantly, with UAV remote sensing, we do not need to block traffic, as is required when we inspect manually.

Think about what happened in Florida last fall. After Hurricane Ian roared through the state, leaving a trail of destruction, we urgently needed to know the condition of such things as bridges and roads, which had become difficult or impossible to access. Drones made it easy to fly over and get closer to the infrastructures, take multiple pictures, and send all the information back to professionals remotely to identify and assess conditions.

Aerial photo shows massive destruction in Fort Myers Beach, Florida, in the aftermath of Hurricane Ian.

Small UAVs are very popular now, and are being used to inspect bridges, buildings, tunnels and so forth. Typically, one operator flies the drones and measures the structures. The measurement work includes taking RGB images (RGB stands for the primary colors red, green and blue, which are used to reproduce a variety of other colors to sense, represent and display an image) of the surface; infrared images of the components; and 3D point clouds (sets of data points in space).

All these data can be saved onboard or sent back to the control hub wirelessly. Using customized post-processing algorithms, we can detect whether there is damage, and if so, determine its location and severity.

My research lab is developing novel sensors and damage detection algorithms that can be integrated with UAVs. This work includes collaborating with researchers from my previous institution, East Carolina University, who are working on a North Carolina Department of Transportation-supported project.

Purdue and its Institute for Control, Optimization and Networks (ICON) also are pushing forward to enhance drone technology development. ICON integrates interdisciplinary expertise to tackle fundamental challenges in complex, connected and autonomous systems. ICON-affiliated faculty across Purdue collaborate with one another and with industry, government agencies, and leaders and experts in the field. Weekly webinars and networking events help to build this teamwork among researchers.

To better apply UAV technologies, one critical issue that needs to be addressed is policy. The Federal Aviation Authority (FAA) currently restricts drone usage under the visual line-of-sight policy, which limits the deployment of drones for large-scale infrastructure inspections.

Also, most inspections are conducted during the daytime and under normal weather conditions. We need more research into how to use drones at night and in strong-wind or low-temperature conditions. Through increased automation, we can preconfigure UAV flight paths and detect damages automatically, which will further reduce human error.

C- or not, things are looking up — for the first time in 20 years, the grade given by the ASCE Report Card for America’s Infrastructure rose from the D range. And Congress in November 2021 passed the Bipartisan Infrastructure Law (Infrastructure Investment and Jobs Act), to ramp up the focus on improving the nation’s bridges and roads, ports, airports, rail, power transmission and distribution, and other infrastructure.

There are a lot of potential benefits for the various stakeholders in the effort to rejuvenate our infrastructure through increasing use of remote sensing via UAVs. Given the national trend and ongoing innovation, I envision more and more UAV-based inspections, leading to more accurate and timely decisions about replacing or better maintaining and repairing infrastructure.

Shanyue Guan, PhD, PE

Faculty Contributor, Institute for Control, Optimization and Networks (ICON), College of Engineering

Assistant Professor, School of Construction Management Technology, Purdue Polytechnic Institute

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