Climate Change Threatens U.S. Bridges

Key Findings from a Recent Study

A recent study published in PLOS ONE, authored by Susan Palu and Dr. Hussam Mahmoud, highlights the growing vulnerability of deteriorating U.S. bridges due to climate change. This research, conducted at Colorado State University, focuses on how rising temperatures and clogged expansion joints could jeopardize the structural integrity of thousands of bridges across the country.

The Researchers Behind the Study

Susan Palu was a master’s student in civil engineering when the study was conducted, bringing fresh academic insight into the challenges of aging infrastructure. Dr. Hussam Mahmoud, a professor at Colorado State University and the George T. Abell Professor in Infrastructure, is a renowned expert in sustainable infrastructure and community resilience. With a Ph.D. from the University of Illinois at Urbana-Champaign and over 300 publications to his name, Mahmoud’s research focuses on making infrastructure systems more resilient to natural hazards, including climate change​.

The Aging U.S. Bridge Infrastructure

As U.S. infrastructure ages, many bridges are approaching or exceeding their intended design life. Approximately 40% of U.S. bridges are over 50 years old, with around 54,560 classified as structurally deficient. While bridges have been inspected and maintained regularly, this study sheds light on a specific issue: malfunctioning expansion joints, small but critical components responsible for allowing bridge expansion and contraction during temperature changes.

Impact of Climate Change on Bridges

he study examines the effects of climate change on steel-span bridges, which were mass-produced during the highway boom of 1950s to 1970s, when the interstate highway system was being developed. These bridges, when subjected to higher future temperatures, are at risk of developing dangerous levels of thermal stress, especially when their expansion joints are clogged.

When debris builds up in these joints, it prevents the bridge from expanding as temperatures rise. This blockage causes axial pressure on the girders, which, combined with the weight of vehicles, could lead to structural fatigue, cracks, and even failure.

Researchers also studied how temperature changes during bridge construction impact their strength.
They looked at four scenarios: building bridges in winter, spring, summer, or fall. They found that:

  • If built in winter, 100% of bridges might be too weak.
  • If built in spring, 97% might be too weak.
  • If built in summer, 83% might be too weak.
  • If built in fall, 95% might be too weak.

Most Vulnerable Regions

The study identifies bridges in the Northern Rockies, Upper Midwest, and Northwest as the most vulnerable, particularly in states like North Dakota and South Dakota. These regions are likely to experience more severe temperature variations, exacerbating the effects of clogged joints and adding stress to already aging structures.

A Call for Action

With over 89,000 simply supported steel girder bridges analyzed, the study advocates for immediate attention to maintaining and clearing bridge expansion joints. It emphasizes that neglecting to address these climate-related challenges could lead to substantial economic and social costs. Prioritizing repair and maintenance will be essential to ensure the safety and longevity of U.S. infrastructure in the face of climate change.

Summing Up

This groundbreaking study, conducted by Susan Palu and Dr. Hussam Mahmoud at Colorado State University, offers critical insights into how climate change is accelerating the deterioration of U.S. bridges. Without intervention, the impact on national infrastructure could be catastrophic. Policymakers, engineers, and transportation authorities are urged to take immediate steps to mitigate these risks and protect public safety.

By staying ahead of these challenges, the U.S. can safeguard its infrastructure from the growing threat of climate change.


Source: Palu, S., & Mahmoud, H. (2019). Impact of climate change on the integrity of the superstructure of deteriorated U.S. bridges. PLOS ONE, 14(10), e0223307. https://doi.org/10.1371/journal.pone.0223307.

Green Horizons: Biden’s Economic Blueprint for Sustainable Growth and Resilience

Civil engineers at construction site. Photo by John Kakuk via Pexels.
Civil engineers at construction site. Photo by John Kakuk via Pexels.

Legislative Milestones and Economic Goals

Between November 2021 and August 2022, President Bident signed into law three significant economic policy laws: the Bipartisan Infrastructure Law (BIL), the Inflation Reduction Act (IRA), and the Creating Helpful Incentives to Produce Semiconductors (CHIPS) Act. These laws aim to significantly boost U.S. investments in clean energy, manufacturing, and infrastructure and thereby create millions of new jobs while also laying the foundation for sustainable economic growth and environmental resilience.

Impact Analysis: Job Creation and Sector Growth

The February 2024 report Labor supply, labor demand, and potential labor shortages through new U.S. clean energy manufacturing and infrastructure laws by Jeannette Wicks-Lim and Robert Pollin, professors at the Political Economy Research Institute (PERI), University of Massachusetts Amherst, considers the BIL, the IRA, and the CHIPS Act in relation to their employment impacts within the U.S. economy.

Construction and manufacturing sectors stand to gain immensely from these policies, with substantial investments earmarked for infrastructure projects, renewable energy initiatives, and semiconductor manufacturing. The service sector is also poised for growth, benefiting from increased demand and investment in green technologies and services.

Occupations in engineering, construction, renewable energy, and technology are witnessing the largest increases in labor demand. These high-demand occupations vary in job entry requirements, offering opportunities for workers with diverse skill sets and educational backgrounds.

Overcoming Labor Market Challenges

While these policies are set to boost job creation, they also pose challenges in terms of labor supply, potentially leading to shortages in certain sectors. A detailed analysis of sectoral and demographic composition highlights the need for strategic interventions to address these gaps.

To mitigate labor shortages, the focus has shifted towards apprenticeships, job training programs, and enhancing the role of community colleges and unions in workforce development. These measures are crucial for equipping workers with the skills needed for the jobs of tomorrow.

Economic and Social Ripple Effects

The ripple effects of enhanced job creation are vast, impacting regional economies and contributing to narrowing demographic disparities in employment. These policies are instrumental in promoting economic equity and social mobility across the United States.

The evolving job market presents both challenges and opportunities for the U.S. workforce. Adapting to new job requirements and investing in upskilling and reskilling are imperative for workers to thrive in this new economic landscape.

Comparative Analysis with Previous Employment Trends

A comparative analysis with previous administrations reveals the significant impact of government policy on job creation and economic growth. The Biden administration’s proactive approach marks a notable departure from past trends, emphasizing long-term investments over short-term fixes.

Final Thoughts

The Biden administration’s economic policy reforms signify a bold step forward. By fostering job creation, stimulating growth, and addressing environmental challenges, these policies are setting the stage for a prosperous and sustainable future. As these policies unfold, their full impact on employment and economic dynamics across the nation will become increasingly clear, heralding a new era of prosperity and resilience for the American workforce. Continuous monitoring of these initiatives’ impact on the job market and the broader economy helps ensure that the benefits are felt by all Americans.

Michigans Dam Failures, a Small Part of America’s Aging Infrastructure Problem

https://youtu.be/pltqZfxwHdo

More than 15,000 of the 90,000 dams listed in the national inventory are designated as having high hazard potential. If they break, the resulting catastrophe is likely to cost lives. If a dam fails catastrophically, huge amounts of sediment can be washed downstream, clouding the water and moving contaminants.

“Dams like that shouldn’t be failing.”

“They should be properly maintained and upgraded. Unfortunately, in many cases they’re not.”

–Mark Ogden, coauthor of an American Society of Civil Engineers 2017 Infrastructure Report Card

Source: Popular Science