Think all bridge inspections are the same? They’re not. In this article, we’ll explain five different types and when they should be leveraged.
Why bridge inspections are important
Millions of people cross bridges throughout the United States every day. All of them depend on bridge inspections to stay safe. The recent bridge inspection failure on the Hernando De Soto Bridge near Memphis has pointed to the importance of them in protecting people from catastrophic accidents and failures.
There has been too little infrastructure funding for decades, which has left many of the nation’s bridges and roads in disrepair. And even though it seems likely that Congress will approve funding to improve the nation’s infrastructure, it will take a long time to complete needed repairs and build new structures. In the meantime, countless viaducts will have been left vulnerable to the effects of traffic, the natural environment and time. It is only through regular ongoing inspections that the signs of wear and tear from these things can be identified so preventative maintenance is able to take place. This can help prevent issues that could lead to accidents or failures.
Another benefit of regular inspections is that they can help governments save money while they wait for infrastructure dollars to come in. It allows them to identify issues sooner, when they’re less expensive to remedy. The longer a defect exists, the worse it gets, and the more it will cost to repair. It helps keep them from becoming high-risk, high-cost problems.
Added benefit: In addition to identifying issues that need to be taken care of, regular bridge inspections allow municipalities to maintain current documentation about the bridges in their care. This will help them set priorities and take advantage of federal infrastructure funds as soon as they come available.
Common types of bridge inspections
Of course, no two bridges are exactly alike, and different structures require different types of inspections, depending on their age, condition, and unique circumstances, such as possible damage after being impacted by a natural disaster, such as an extreme wind event, hurricane, wild fire or earthquake.
The purpose of each type of inspection is to identify issues as efficiently and effectively as possible. Here are some of the most common types conducted by civil engineers and licensed bridge inspectors.
Even brand new bridges have to be looked over by trained professionals. Initial inspections are the very first ones conducted on newly constructed and recently rehabilitated bridges. The Federal Highway Administration (FHWA) recommends that initial inspections happen before bridges are opened to traffic.
The primary purpose of initial inspections is to get a clear picture of the condition of the structure when it’s brand new and it’s integrity hasn’t been impacted by traffic. They can also identify construction or engineering problems, along with sections of bridges that may need closer monitoring in the future. Even new bridges can have components that are problematic.
These are the most common types of bridge inspections. They’re conducted periodically to gauge the overall condition of a bridge — or sections of it — and look out for opportunities for improvement and needed maintenance.
The United States Department of Transportation (DOT) recommends that routine inspections be performed every two years. Older or more vulnerable structures may require more frequent inspections. Newer ones with no issues may be allowed to undergo fewer inspections is they receive special approval.
Sometimes routine inspections aren’t adequate to identify elusive structural problems. That’s when an in-depth inspection is necessary. They’re usually handled by two or more licensed bridge inspectors, who often have specialized knowledge or training. If a bridge crosses water, an in-depth inspection may take place below the body of water . Depending on the circumstances, specialized equipment like scuba gear, drones and lifts, like those offered by Bridge Masters, are needed.
In-depth inspections aim to identify structural deficiencies, signs of deterioration and damage that could lead to partial failure or total collapse. Good record keeping can help improve the effectiveness of in-depth inspections because understanding the condition of a structure when it was previously looked at makes it possible to track deterioration and changes of condition.
Emergency inspections, often referred to as damage inspections, are performed right after a natural disaster, accident, human error or other occurrence that could negatively impact a bridge’s structural integrity or ability to function. Often, specialized crews are brought in who have the knowledge and training it takes to identify damage related to these incidents. Bridges are usually closed to the public during these types of inspections to prevent safety issues and protect people. Traffic is only restored when inspections are complete and no dangerous structural issues are found.
A specialized inspection is often necessary when there is a known or suspected issue on a bridge that requires ongoing monitoring while awaiting repairs. These types of things are typically found in the cables, foundation or support structures. When these issues are identified, cameras, detectors and sensors are often installed to monitor structural changes. Traffic can be immediately shut down if dangerous changes are detected.
Until the nation’s bridges are restored to sound working condition, officials need to be prepared to conduct the right inspection for the situation.