One year after the Key Bridge collision in Baltimore, a team of Johns Hopkins students has helped identify which major bridges might be next.

On March 26, 2024, a container ship accidentally struck the Francis Scott Key Bridge in Baltimore, causing a collapse that killed six people. At the time, Michael Shields, a HEMI fellow and associate professor at Johns Hopkins University, described the collision as “a wake-up call.” If a Baltimore landmark like the Key Bridge, which had carried more than 30,000 vehicles across the Patapsco River each day, was so vulnerable to collapse, what did that mean for other American bridges?

With the help a Rapid Response Research grant from the National Science Foundation, Shields immediately got to work forming a team of students to help him assess the country’s bridges and develop new risk models.

Now, a year later, the team has grown to 13 students and two other faculty members. The undergraduate and graduate researchers are responsible for a wide variety of crucial tasks, including analyzing dozens of bridges, writing programs to collect data from the Internet, and building a virtual portal to report the project’s findings. All of this allows the team to consolidate vast amounts of information to calculate the current stresses on major American bridges and pinpoint the most vulnerable ones.

“I’ve guided the direction—steered the ship, if you will—but the students have done a tremendous amount of the work,” Shields says. “They are the lifeblood of the project. Without them, we can’t accomplish what we need to accomplish.”

So far, Shields’s team has identified 19 major American bridges that can expect a collision strong enough to cause catastrophic damage or collapse within the next 500 years, including San Francisco’s iconic Golden Gate Bridge and Maryland’s Chesapeake Bay Bridge. This is dangerously high, especially since bridge design standards stipulate that the risk be closer to once every 10,000 years.

These are findings with serious implications that Shields hopes will inspire real-world change, all thanks to the work of student researchers.

As the nation’s first research university, JHU puts an emphasis on giving students opportunities to get involved in research projects. According to graduate researchers Damir Akchurin and Promit Chakroborty, who manage the undergraduate researchers on Shields’s team, being involved in a project like theirs is a key part of the Hopkins experience. Eighty percent of undergraduate students leave the university having contributed to research.

“At this particular institution, it is kind of inevitable,” Akchurin says. “There are so many opportunities coming up every semester. … The only thing that you need to do is make one small step by reaching out to the professors and asking.”

Adds Chakroborty: “Most research projects require tasks at all levels of expertise. There’s always something that can be found to fit your tastes and your niche.”

Shields’s team meets every Friday afternoon to discuss that week’s findings and assign new tasks. Student researchers of all levels present new breakthroughs in their work.

One of these researchers is junior Diran Jimenez. Despite having little experience, Jimenez says that his ideas and input are always valued by the group.

“I’ve gotten to do a lot of really high-level stuff,” he says. “When I say we shouldn’t do X because of Y, that’s taken into account. That’s real input that you can see the results of in the future. And a lot of the numbers I’ve put together are relied on by everyone, which is really rewarding because I’ve really contributed to this project.”

Senior Natalia Dougan, another undergraduate researcher on the team, echoed Jimenez. She added that being part of a research project gave her new insights into what she wants from her career.

“This experience definitely changed what I thought that I was looking for,” she says. “I had no intention of ever pursuing any research position or academia. …. Now I’m more inclined to want a position where the research process is part of my day-to-day.”

According to Shields, revelations like Dougan’s are common among undergraduate researchers. After all, it happened to him.

“I decided to become a professor and a researcher professionally because of my experiences as an undergraduate researcher,” he says. “When I was an undergraduate, I had an opportunity to spend a couple of years as an intern at Argonne National Laboratory, and that really shaped my career trajectory. … Having those types of opportunities for undergraduate students can really be life-changing. Even for students who may not want to be a researcher long-term, the abilities that they develop to ask probing questions and to think critically are going to be helpful for them.”

This story by Claire Goudreau originally appeared in The Hub.

New analysis by Johns Hopkins researchers finds some bridges are likely to sustain catastrophic hits within the next few decades

Ships are highly likely to collide with major bridges across the United States, with potentially catastrophic collisions happening every few years, according to preliminary findings of an urgent assessment of the nation’s bridge vulnerability following the 2024 Key Bridge collapse in Baltimore.

Though ship strikes should be extremely rare—and bridge design standards stipulate that the annual chances of a bridge collapse from ship collision should be less than 1 in 10,000—some of the nation’s busiest bridges will likely be hit by ships within our lifetime, according to the findings released today by Johns Hopkins University. The most vulnerable bridges, including the Huey P. Long Bridge outside New Orleans and the San Francisco-Oakland Bay Bridge, are likely to be hit by a ship within about 20 years, the study found.

“With this investigation we wanted to know if what happened to the Key Bridge was a rare occurrence. Was it an aberration? We found it’s really not,” said Michael Shields, a HEMI fellow and Johns Hopkins engineer specializing in risk assessment and lead investigator of the National Science Foundation–supported study. “In fact, it’s something we should expect to happen every few years.”

A year ago, Baltimore’s Francis Scott Key Bridge collapsed after a direct hit by a massive container ship. Believing chances were high for another such incident, and that risk to the Key Bridge amid modern shipping traffic had been underestimated, Johns Hopkins engineers immediately launched a risk assessment for U.S. bridges.

The team aimed to estimate the actual chances a large ship would hit the country’s most significant bridges.

They collected and mined 16 years of U.S. Coast Guard data—logs detailing the precise location, heading, speed, and status of every ship traveling through the country’s waters on a minute-by-minute basis. They cross-referenced the geolocated shipping information, hundreds of millions of data points, with port data and bridge data from the National Bridge Inventory to determine which large ships passed under bridges.

Using this traffic data, along with ship aberrancy rates adopted from the American Association of State Highway and Transportation Officials, the researchers estimated the probability of very large ships colliding with the piers of major bridges across the U.S.

The results revealed stark vulnerabilities for many bridges. Several bridges could expect a major ship collision—a collision strong enough to cause catastrophic damage or collapse—at least once every 20 to 50 years. Many others are likely to sustain a ship strike within 100 years.

The Key Bridge would have been among the 10 most vulnerable bridges in the country, according to the team’s calculations. They predicted it would have likely been hit by a ship within 48 years. The bridge was 46 years old when it fell—and it had sustained a minor hit from a ship previously.

“To keep our bridges safe and operational, we want the chances of a collision strong enough to take down the bridge to be less than one in 10,000 in a given year, not one in a 100. One in 100 is extremely high,” Shields said. “If I look at the San Francisco Bay Bridge, we’re likely to see a major collision once every 22 years. That is huge. We want that number to be thousands of years. That’s tens of years.”

According to preliminary results, the most vulnerable bridges are:

• Huey P. Long Bridge, Louisiana: Collision expected once every 17 years
• San Francisco–Oakland Bay Bridge: Collision expected once every 22 years
• Crescent City Connection, New Orleans: Collision expected once every 34 years
• Beltway 8 Bridge, Texas: Collision expected once every 35 years
• Hale Boggs Memorial Bridge, Louisiana: Collision expected once every 37 years
• Bayonne Bridge, N.Y./N.J.: Collision expected once every 43 years
• Fred Hartman Bridge, Texas: Collision expected once every 47 years
• Martin Luther King Bridge, Texas: Collision expected once every 64 years
• Sunshine Bridge, Louisiana: Collision expected once every 71 years
• Rainbow Bridge, Texas: Collision expected once every 71 years
• Veterans Memorial Bridge, Louisiana: Collision expected once every 74 years
• Chesapeake Bay Bridge, Maryland: Collision expected once every 86 years
• Talmadge Memorial Bridge, Georgia: Collision expected once every 88 years
• Veterans Memorial Bridge, Texas: Collision expected once every 94 years
• Delaware Memorial Bridge, Del./N.J.: Collision expected once every 129 years
• Dames Point Bridge, Florida: Collision expected once every 152 years
• Horace Wilkinson Bridge, Louisiana: Collision expected once every 198 years
• Verrazzano-Narrows Bridge, New York: Collision expected once every 362 years
• Golden Gate Bridge, California: Collision expected once every 481 years
• John A. Blatnik Bridge, Minnesota/Wisconsin: Collision expected once every 634 years

Some bridges with considerable traffic from large ships did not make the list because their piers are safely on land, away from the passing ships. Those include Minnesota’s Duluth Lift Bridge and the Vincent Thomas Bridge in California.

Because no two bridges are the same, what happens in the event of a collision is very different from bridge to bridge, Shields said. While a large ship collision would not necessarily result in a bridge collapse, Shields said it would almost certainly cause irreparable damage and very likely cause at least a partial collapse.

“If one of these massive ships hits a bridge, it’s catastrophic,” he said.

To lower the risk for these bridges, the critical thing is to keep ship traffic away from the piers, and to outfit them with robust protections including dolphins and other structures that keep ships from approaching the piers.

“There’s still a lot of uncertainty in predicting the frequency of ship collisions, even with the best data we have,” Shields said. “But the important point is not whether it will occur every 17 years or every 75 years. It’s that it’s happening way too often.”

The team included structural engineer Ben Schafer, the Willard and Lillian Hackerman Professor; Rachel Sangree, a structural engineer and teaching professor with bridge inspection experience; Promit Chakroborty and Damir Akchurin, PhD students in Civil and Systems Engineering; Adwait Sharma, postdoctoral fellow in Civil and Systems Engineering; Johns Hopkins undergraduate and master’s students Diran Jimenez, Natalia Dougan, Yile Wang, Jenna Halpin, Diana Arizmendi, Lemon Doroshow, Yun Tang, JunYup Kim, Alek Ding, and Ololade Akinbamilowo; and Morgan State undergraduate Esther Ezeigbo.

This story by Jill Rosen originally appeared in The Hub.

Johns Hopkins structural design and resilience expert Thomas Gernay says fire-resistant building designs are key to protecting communities from increasingly destructive wildfires

The Eaton and Palisades fires recently destroyed or damaged more than 12,000 structures—including the iconic Malibu restaurant Moonshadows, the Palisades library, and the Palisades Charter High School—across Los Angeles County. Tens of thousands of residents have been displaced.

As firefighters continue to battle wildfires in the area, municipal leaders are starting to think about rebuilding efforts. Thomas Gernay, a HEMI fellow and assistant professor in the Department of Civil and Systems Engineering at Johns Hopkins University, has spent years studying fire-resistant buildings.

Here, Gernay offers insights into how California should approach rebuilding.

What are your observations of the California wildfires?

We examine these disasters to understand how we can change the built environment to prevent them from happening again. There are more than 10,000 structures that have been destroyed so, of course, there are immediate questions and economic policy aspects. But from the engineering perspective, it’s also, how are we going to rebuild? What kind of design decisions can we make on the built environment so that this kind of disaster does not happen again and in other communities?

Some aspects of these fires have to do with the layout of the communities or the interaction with the vegetation. California already had mandates, such as cleaning up vegetation around houses, but obviously they were not sufficient. Because there are such strong interactions between different structures, if one neighbor takes measures to harden their own house, it decreases the odds of an ignition for the surrounding houses. Inversely, if one homeowner does not implement proactive measures, it defeats the purpose for everyone.

What do engineers need to consider when designing buildings to prevent this?

Civil engineers need to think about how to harden structures so that they don’t catch fire in the first place. Sometimes we will lose a few structures, but we hope they don’t generate those embers that spread the fires. The choice of materials, for things such as roofing, decks, vents, and windows, will influence the chances that the house gets ignited and escalates the fires.

If you were to make a recommendation to the L.A. County government, what would it be?

We don’t have all the solutions, but I would recommend that we have to have a shift in thinking about these disasters. When conditions are extreme, such as they were in California, with wind and drought, it’s really hard to rely on fire suppression and suppressing emission. So there is a component of it that is about urban configuration. We need to think about what happens if a wildfire starts and gets into the community.

As we rebuild, we need to think about building materials, construction practices, layout of the communities, and more. Of course that’s upstream and not something that’s easy for the local government to do, but I don’t think it’s sufficient to work only on ignition suppression. There is work to do on the built environment, similar to what has been done for decades against earthquakes in California.

What technological advancements are helping architects design safer buildings?

We developed a software, called SAFIR, that simulates the response of the structural part of a building under fire. A user can input a fire scenario and the software will compute the temperature elevation in the structure, and then the deformation or collapse.

But some of this knowledge is not applicable to wildfires because what is important for wildfires is whether it will catch fire, more than the structural response. So some aspects of the software we are looking at are heat transfer, which is useful, but there are new, important developments that are needed if we want to look at how fires spread in communities.

With climate change increasing the frequency of events like this, how do you see this field evolving over the next 10-20 years?

I think a lot of advances will happen against wildfires. Traditionally, the field has been investigated by ecological science and forest management, but there is a blind spot in terms of how those fires spread in cities, so we don’t have models that are simulating how fires, such as in Palisades, spread. Those models would be very important during fires to support better evacuation, allocation of resources, and to prepare pre-fire.

If we have simulation capabilities for wildfires, we can study scenarios before they happen. You can take a city, such as Los Angeles, and say, “OK, what would happen if we have a fire that starts here?” Then, you can run it again if a community takes some of the protective measures, such as cleaning up the vegetation, making sure vents are closed, or changing construction materials.

In those scenarios the software can evaluate losses, damages, and people that are displaced. You can then evaluate the impact of different measures—not only for policymakers, but for insurance companies and more.

So there is research happening in that space, but we aren’t there yet. It requires complex physics. I think we will have great advances in those kinds of tools, and that will equip us better to mitigate against these wildfires as they are becoming more frequent and more destructive.

This article originally appeared on Hopkins Bloomberg Center website.

Believing chances are high for ships to hit United States bridges, like the catastrophe in Baltimore, Johns Hopkins University engineers have begun what they consider to be an urgent assessment of the country’s bridges, particularly the larger ones near major ports of entry.

“We need to know now, not five or 10 years from now, whether there is an outsize risk to bridges across the country so that critical investments—which will take years—can begin immediately if they are needed,” said team leader Michael Shields, a Johns Hopkins engineer specializing in risk assessment. “The Key Bridge collapse was a wake-up call.”

With a National Science Foundation Rapid Response Research grant and the help of an “army” of students, the team will attempt to modernize risk prediction models, as the nature of shipping, particularly the prominence of massive cargo vessels, has increased considerably in the decades since most of these bridges were built.

“Clearly the risk to the Key Bridge was very different in 2024 than it was in 1977 when the bridge opened,” Shields said. “But we don’t currently understand that risk.”

The team hypothesizes that the risk of the Key Bridge collapse was underestimated and that the probability of another catastrophic collision in the United States is likely “much higher” than current design standards presume.

The team will try to answer questions including:

• What is the probability that a ship the size of the Dali would stray from its path and collide with the Key Bridge?
• What are the chances for similar bridge collisions across the country ?
• Have we underestimated the probability of collision and ultimately the probability of failure of critical U.S. bridges?

The team will mine global shipping data, develop modern risk models, and then attempt to identify which critical U.S. bridges are vulnerable to a catastrophic ship collision. Using the shipping data, they will build models to determine the probability of a ship deviating from course and hitting a bridge in or around major ports.

“Preliminary findings already challenge prevailing assumptions,” said team member Rachel Sangree, a structural engineer and former bridge inspector. “The U.S. has seen 17 incidents of major bridge collapse between 1960 and 2011, averaging one every three years. Between the exponential growth of mega freight ships and the surge in global shipping traffic, many of our bridges simply weren’t built to withstand the pressures of today’s maritime landscape.”

The findings will help policymakers prioritize infrastructure improvement spending.

“The team’s findings will be crucial in reassessing and potentially redefining the safety standards for transportation infrastructure,” said structural engineer Ben Schafer, the Willard and Lillian Hackerman Professor of Civil and Systems Engineering. “Given the estimated $1.7 billion to $1.9 billion cost to rebuild the Key Bridge and the potential billions needed to retrofit existing bridges, accurate risk assessment is vital to ensure the sustainability of society’s critical infrastructure.”

The team has already begun its investigation and hopes to share some preliminary results with stakeholders by the end of the summer, with the full study taking approximately one year to complete.

This story originally appeared in The Hub.

Stavros Gaitanaros’ innovative research focuses on the mechanics of “architected materials” – a a class of materials with exceptional mechanical, acoustic, and thermal properties and unlimited potential in a variety of applications, from space structures and energy storage devices to biomedical implants.

In the interview below, the assistant professor in the Department of Civil and Systems Engineering, fellow in the Hopkins Extreme Materials Institute and the Johns Hopkins Center for Additive Manufacturing and Architected Materials (JAM²), and leader of the Extreme Mechanics of Architected Materials group, shares thoughts on his field, his research program, and the future.

What are the most important problems in your field today?

A wide range of global challenges, from space exploration to modern infrastructure and health, require the design and discovery of new materials with multiple functionalities that provide resilience and sustainability.

Which of those problems are you tackling through your research, and why did you choose them?  

My research focuses on novel lightweight materials with excellent combinations of mechanical, acoustic, and thermal properties, that are derived by the underlying material architecture – a combination of geometry and distribution of matter. Architected materials are characterized by their mesostructure, meaning their morphological features are larger than the atomic scale but still small enough to be classified as a material (one can think of a sponge). Varying the geometric features of this mesostructure and combining them with any typical solid leads to a plethora of material systems with distinct behavior, in a similar manner to material scientists using chemistry and the periodic table to create new alloys. It is actually a concept that nature employs to generate all of its essential structures, from honeycombs and bone to wood and plant stems. It is this unique combination of geometric design and mechanics, applied to both biological and engineered materials, that drew me to this field.

Does your current research seek to answer a fundamental question in science, or does it have potential practical ramifications? Tell us more about that.

My research group is particularly interested in the extreme mechanics of architected materials, which entails their response under large deformations–how they fail, how much energy they can absorb under impact loads, how waves propagate through them, or how they collapse under high temperatures. Our work aims to advance our fundamental understanding of architected materials and develop the necessary computational tools that will enable their systematic design and analysis. Our findings have a far-reaching impact on a broad spectrum of engineering applications, from resilient space structures to soft scaffolds for tissue engineering.

How is your approach to the problem better, more innovative, more promising, or just different than the approach others in your field are using?

The effective blend of different techniques including geometric design, additive manufacturing, computational modeling, theory, and, as of recently, data-driven methods, defines the identity of our group and our unique approach to solving these complex problems.

What has been your most significant finding so far? How about your most surprising finding?

Quantifying significance is tough so I will borrow a passage from Leo Tolstoy’s diaries instead: “There is only one significance, you are a worker. The assignment is inscribed in your reason and heart and expressed clearly and comprehensibly by the best among the beings similar to you. The reward for doing the assignment is immediately within you. But what the significance of the assignment is or of its completion, that you are not given to know, nor do you need to know it. It is good enough as it is. What else could you desire?”

A surprising finding, or at least counterintuitive at first, is that a certain amount of disorder in materials is almost always beneficial (the philosophical extrapolation is rather amusing…).

What other engineer or scientist in your field has influenced you? How?

If I had to choose one, it would be Theodore Von Karman for his enormous body of work in fluid and solid mechanics, and the way he integrated (if not transcended) engineering, applied mathematics, and physics. He is mostly known for his work on aerodynamics but his studies on the mechanics and instabilities of thin plates and shells are, in my opinion, equally important. I would urge any engineering student to find his paper “The engineer grapples with nonlinear problems” or even better read one of his books (if the 5-volume collected works of his seems too heavy of a task).  Von Karman is also an academic ancestor of mine, so I have to acknowledge some level of bias in my choice.

Do you expect to continue working on the same problem five years from now? How about 10? If not, what other research avenues do you anticipate exploring?

My long-term to-do list involves a bunch of diverse problems, from seismic metamaterials and plant mechanics to physics of bubbles, that I really hope I’ll get to explore in the future.

Anything else you want to add?

This Q&A was harder than I initially thought, like a Marcel Proust questionnaire tailored for scientists!

This Q&A was excerpted from the Department of Civil & Systems Engineering. You can read the complete story here.

Lori Graham-Brady, HEMI associate director and professor in the Department of Civil and Systems Engineering and KT Ramesh, the Alonzo G. Decker Professor of Science and Engineering and director of HEMI, were awarded best papers by the Journal of the American Ceramic Society. On October 11, 2022, their winning papers were presented at a special awards symposium at the Materials Science and Technology Technical Meeting and Exhibition in Pittsburgh, Pennsylvania.   

Graham-Brady’s paper is titled, “Fragmentation and Granular Transition of Ceramics for High Rate Loading,” and included co-authors Amartya Bhattacharjee and Ryan Hurley of Johns Hopkins University. 

“Models for the Behavior of Boron Carbide in Extreme Dynamic Environments,” is the title of K.T. Ramesh’s winning paper. Co-authors included: Lori Graham-Brady, Ryan Hurley, Mark Robbins, Amartya Bhattacharjee, Qinglei Zeng, Weixin Li, and Nilanjan Mitra from Johns Hopkins University; William Goddard, California Institute of Technology; Andrew Tonge, DEVCOM Army Research Laboratory; Joel Clemmer, Sandia National Laboratories; and Qi An, University of Nevada, Reno. 

Both papers were the result of research conducted in the Center for Materials in Extreme Dynamic Environments(CMEDE), a center within the Hopkins Extreme Materials Institute. Funded by the DEVCOM Army Research Laboratory, CMEDE research has developed a materials-by-design process for protection materials which have military armor applications.    

After a two-year delay due to COVID-19, the International Conference on Multiscale Materials Modeling (MMM) was held in October 2022 in Baltimore, Maryland. Johns Hopkins University’s Jaafar El-Awady, professor of mechanical engineering, and Somnath Ghosh, M.G. Callas chair and professor of civil and systems engineering, served as chair and co-chair respectively. 

A forum for researchers from academia, national laboratories, and industrial research facilities worldwide with interdisciplinary research backgrounds including mechanics, materials, biomechanics, mechanobiology, advanced manufacturing, mathematics, and computational sciences, the MMM conference is held biennially. It was first held in 2002 in London and the location rotates sequentially between North America, Europe, and Asia.  

The MMM conference is highlighted by four distinguished plenary speakers and eight semi-plenary speakers. The technical program includes 27 technical symposia as well as a dedicated poster session. More than 750 individuals participated in the conference. Conference sponsors included: Johns Hopkins University, George Mason University, Georgetown University, the University of Maryland, and the Hopkins Extreme Materials Institute.  

Congratulations to the recipients of the 2022 HEMI Seed Grants: Prof. Yayuan Liu, Dr. Chao He, and Prof. Dimitris Giovanis!

Liu is an an assistant professor in the Department of Chemical and Biomolecular Engineering and an associate faculty member in the Department of Materials Science and Engineering. Her accepted proposal is titled “Designing Vascularized Porous Electrodes with Enhanced Ion Transport for Battery Extreme Fast Charging.”

He is an associate research scientist in the Department of Earth and Planetary Sciences. His accepted proposal is titled “Spectral signature of prebiotic molecules in Titan’s surface materials.”

Giovanis is an assistant research professor in the Department of Civil and Systems Engineering and Fellow within HEMI. His accepted proposal is titled “Data Driven Uncertainty Quantification for Energetic Materials.”

Each HEMI Seed Grant awards $25,000 to each recipient for the effective award period of September 1, 2022 to August 31, 2023. They are given each year to fund research in fundamental science associated with materials and structures under extreme conditions. All faculty and researchers at the Johns Hopkins University, as well as Applied Physics Laboratory (APL) staff, who can serve as Principal and Co-Investigators are eligible to apply. Learn more about the program here.

Somnath Ghosh, HEMI Fellow and Michael G. Callas Chair Professor in the Department of Civil and Systems Engineering, has been awarded the 2022 Raymond D. Mindlin Medal by the American Society of Civil Engineers (ASCE). Given annually, this medal recognizes an individual’s outstanding research contributions to applied solid mechanics.

Somnath was honored for “outstanding novel contributions to the field of computational mechanics of materials through development of fundamental concepts in spatio-temporal multi-scale, multi-physics modeling of metals, composites and multi-functional materials, and bridging the mechanics and materials communities through strong interdisciplinary leadership.”

Somnath’s research focuses on computational engineering and sciences integrating computational mechanics, computational materials science, and integrated computational materials engineering, with an emphasis on multiscale multi-physics modeling, materials characterization, machine learning, and uncertainty quantification.

He has been invited to accept this award in person at ASCE’s annual Engineering Mechanics Institute Conference, to be held in Baltimore from May 31 through June 3.