Transportation Troubleshooting: America Uses 50-Year-Old Guidelines To Inspect Bridges in 21st Century
Every government experiences a “feel good” moment upon announcing infrastructure spending plans. President Joe Biden’s proposed infrastructure budget, like previous infrastructure plans, includes significant funding for “transportation infrastructure” such as bridges.
True enough, statistics point to an increasingly grave situation concerning the U.S. bridge network. The 2021 Bridge Condition Report produced by the American Road and Transportation Builders Association (ARTBA) states that according to the latest federal data analysis, 220,000 bridges in the United States—36 percent of bridges in the country—need repair, while another 79,500 bridges require replacement. This doesn’t take into account county bridges and smaller bridges in individual neighborhoods.
Statistics such as these often are quoted to emphasize the need for more federal funding. But the reality is that colossal budgets already are being spent, year after year, on inspection, repair and maintenance of America’s aging bridge system. In fact, all major bridges in the national bridge inventory system, which amount to more than 600,000, are scheduled to be inspected every two years.
Then why are bridges continuing to deteriorate and collapse despite all the money spent repairing them? The reason is stark and undeniable: America’s bridges are collapsing not due to a lack of budget, but to persistent use of obsolete bridge-inspection methods.
While advocating repair and maintenance of bridges, policymakers continue to ignore the need for technology-based bridge inspection. And it’s nothing if not tragic that the technology is readily available, but the United States continues to rely on subjective judgements of manual inspection methods at least 50 years old.
Processes Old and New
More than 50 years ago, U.S. federal and state guidelines for bridge inspections focused on what was seen through the naked eye and discovered by pinging the bridge’s surface with a hammer or dragging a chain across the bridge surface. And all the while, traffic would be continuously speeding along an open lane a few feet away, hindering accurate diagnosis.
Yet inspections are critical to understand the health of bridges, as various factors contribute to weakening their serviceability and shortening their lifespan, including material deterioration, fatigue, vibrations, foundation-integrity issues, design flaws, and consistent loads and overloads on the bridges. Moreover, extreme weather conditions exacerbate underlying issues. Intense heat can warp concrete and steel, while salting of bridges in harsh winters corrodes steel.
While archaic manual inspections can only expose problems conspicuous on the exterior, the issues, by that time, would have become dangerous and expensive, sometimes even too late to fix. By then, the entire structure often has to be replaced at tremendous cost.
On the other hand, robotics can detect issues early in the bridge lifecycle, and nondestructive testing technology (NDT) can penetrate the interior of a bridge structure, uncovering what’s invisible to the naked eye. Technology can record quantitative data that are invaluable to bridge inspectors to analyze bridge conditions in real time. The slightest anomaly will draw attention to a condition that may not yet have turned into a problem. The data recorded will pinpoint the exact location where a problem is in the making, which will allow inspectors to use their extensive knowledge and experience to brainstorm viable options to arrest the problem at a fledgling stage.
Moreover, when deterioration is discovered early in the bridge lifecycle, asset managers can budget more efficiently, prioritize early repairs—with public safety in mind—and extend the service life of the structure, saving billions of dollars in untimely replacements.
Blazing the Trail
With this goal, a Florida-based robotic engineering firm, Infrastructure Preservation Corporation (IPC), has trailblazed technology-based bridge inspection methods that directly contrast with the ancient ones currently in use.
IPC engages NDT in robotic systems to identify deterioration in concrete and other structural material at the initial stages. In fact, IPC has taken modern technology to another level by producing custom-built robotics that enable quantitative results. With these results, IPC can provide an action plan for repairs before deterioration spreads and compromises the safety of bridges.
Moreover, IPC has shown how robotic devices can provide precise quantitative data for an entire bridge, not just for sections of it. And the data obtained are decisive enough to expose any problem minutely, cluing in on anything irregular, even before the issue becomes a problem.
Despite this, Doug Thaler, the president of IPC, is frustrated by the apparent refusal of federal and local authorities, as well as large companies, to incorporate technology in inspections. “How can you repair something when you don’t understand what is wrong to begin with?” he asks.
As Thaler has observed, manual inspections are so subjective that 10 different inspectors could give 10 different reports upon inspecting the same bridge.
Thaler explains that modern technology and robotics provide more quantitative data for less money and exceed the requirements of Federal Highway Administration (FHWA) and American Association of State Highway and Transportation Officials (AASHTO), the two agencies that set the standards for these inspections.
“Typically, and unfortunately, change only takes place after a catastrophe,” adds Thaler. “After the I-35 collapse of 2007 in the United States, new regulations were released.”
In the I-35 bridge collapse of 2007, 13 people died, 145 were injured and 111 vehicles were destroyed. Investigations revealed a design anomaly in the bridge that went unnoticed because locating design errors isn’t standard practice for manual bridge inspections. Yet it was an accident waiting to happen since the bridge opened for business, because what should have been the strongest part of the bridge, was, in fact, one of its weakest.
Many years later, in Genoa, Italy, in August 2018, a bridge popularly known as “Ponte Morandi” after its structural designer, Riccardo Morandi, and an engineering and architectural landmark since its construction, collapsed, killing 43 people.
The list of similar disasters is lengthy, and the damage to human life, adjacent homes, vehicles and the economy is unfathomable.
If instead of manual inspections, engineering firms used advanced robotic systems, engineers would be instantly alerted by abnormal data in specific areas. Immediate action could be taken, well ahead of any catastrophe. Further, ground-penetrating radar (GPR) is a geophysical locating method employing radio waves to capture underground images in a minimally invasive manner.
And all this is possible with existing Department of Transportation budgets. What’s needed isn’t more funds, but a fundamental change in perspective.
Currently, engineering firms have no incentive to replace man hours with modern technology, because the federal government funds man hours. The more hours billed; the more funds received. This makes it imperative that the entire concept of inspection changes immediately. Otherwise, tax dollars and safety will continue to be compromised.
The money currently spent on bridges is bad economic management. America’s bridges can be meaningfully repaired and maintained only by understanding what goes on within the bridge. Such quantitative data can only be obtained by employing technology.
About Rajika Jayatilake
Rajika Jayatilake is a journalist currently engaged in research and writing on issues facing the national construction industry; email: [email protected].
