February 16, 2024
Rust on bridges poses a significant challenge to infrastructure durability and safety, as it can compromise the structural integrity of these vital components of our nation’s transportation system. As bridges play a crucial role in connecting communities and facilitating everything from delivering goods to the average worker’s daily commute, addressing the issue of rust becomes imperative for ensuring public safety and maintaining the longevity of these essential structures.
This blog delves into just that — the causes of rust formation on bridges, its detrimental effects, and how to prevent rust. Understanding the complexities of rust on bridges is essential for engineers, policymakers, and the general public alike, as it sheds light on the ongoing efforts to enhance the resilience and reliability of our infrastructure. Before we can learn how to prevent rust on metal, it’s important to understand why it happens in the first place.
What Causes Rust on Bridges?
Rust formation on bridges is primarily caused by the exposure of metal components, such as steel, to environmental elements. The process of rusting, scientifically known as corrosion, occurs when iron or steel reacts with oxygen and moisture in the presence of electrolytes, such as salts.
Being outdoor structures and by their very nature near water, bridges are constantly exposed to varying weather conditions, including rain, snow, and humidity. All of these environmental factors accelerate the corrosion process, leading to the development of rust on the metal surfaces of bridges. Additionally, pollutants in the air, such as industrial emissions and salt used for de-icing roads in colder climates, can further contribute to the corrosion of bridge materials.
The cumulative effect of these factors poses a significant challenge to structural integrity of bridges. Proactive measures to rid these critical infrastructure components of rust is vital.
What Risks Are Associated With Rusty, Corroded Bridges?
Rusty and corroded bridges pose a range of serious risks that can compromise both public safety and the structural integrity of the bridges themselves. These are some of the key risks associated with rusty, corroded bridges.
Structural Weakness
Rust weakens the metal components of bridges, reducing their load-bearing capacity and overall structural strength. This can lead to a higher risk of collapse or failure, particularly under heavy loads or adverse weather conditions.
Completely shutting down a bridge that is found to be so weak that it’s become a danger is a serious matter. Bridges are critical components of transportation networks, and the closure or restricted use of a bridge due to corrosion-related concerns can disrupt the flow of traffic, impact commerce, and even hinder emergency response efforts.
Safety Hazards for Vehicles and Pedestrians
Corroded bridges that are so far gone they have flaking rust and weakened supports pose a hazard to vehicles and pedestrians. The potential for falling debris or structural failures such as a collapse can result in accidents, injuries, and fatalities.
Increased Maintenance Costs
Regular maintenance and repair costs escalate when dealing with rust-related issues. The battle against corrosion after it has taken hold of a metal structure requires substantial financial resources to address and rectify. We’ll discuss this in more detail further on in this blog.
Investing in the resilience of bridge infrastructure is crucial to ensuring the safety and reliability of transportation systems for communities at large. Addressing these risks requires a proactive approach to bridge maintenance, including regular inspections and the implementation of corrosion prevention measures.
How To Prevent Rust on Bridges
It is absolutely essential to prevent rust on metal bridges, and thankfully it isn’t that difficult to do either. Preventing rust on bridges can be effectively achieved through the application of a cold galvanizing compound. Cold galvanizing is a process that involves applying a zinc-rich coating to the surface of metal structures, providing a protective barrier against corrosion.
Of course, you’re going to want to choose a high-quality cold galvanizing compound that contains a significant percentage of zinc. Zinc acts as a sacrificial anode, corroding in place of the underlying steel and providing corrosion protection. For this reason, the application of a cold galvanizing compound can provide a durable and effective protective layer against rust on bridges, extending their service life and minimizing the need for frequent maintenance and repairs.
If you’re in charge of a bridge, we encourage you to implement a routine inspection schedule to monitor the condition of the bridge and determine when it’s time for a new cold galvanized coating. Touch up any damaged or worn areas promptly to maintain the effectiveness of the protective barrier.
The Cost of Doing Nothing
The American Society of Civil Engineers (ASCE) regularly assesses the nation's infrastructure and provides a comprehensive report card. In their 2021 Infrastructure Report Card, the ASCE gave the overall infrastructure a grade of C-, a grade that hasn’t risen since. The report estimated that there is a cumulative infrastructure investment need of $2.59 trillion over the next 10 years. Their report estimated costs in different sectors, including $125 billion needed for America’s bridges to bring the infrastructure to a state of good repair by 2030.
The price tag of addressing America's infrastructure problems is substantial, yet it costs significantly less to properly maintain bridges and keep a coat of cold galvanizing compound on them to prevent rust on metal. Regular maintenance and upkeep not only saves lives and keeps our transportation system running smoothly, it also costs much less than letting a bridge fall into disrepair. For additional information on the cost of using ZRC versus letting rust take over a metal structure, we broke it all down into hard dollar figures for you. Download our free guide, The Total Cost of Corrosion: Comparing Using ZRC vs. Replacing the Metal Structure, to dig deeper.