Notre Dame engineers work to build climate-resilient homes
As the nation nears the peak of the Atlantic hurricane season, a Notre Dame team of civil and environmental engineers is working make more homes climate-resilient.
Led by Tracy Kijewski-Correa, professor of civil and environmental engineering and earth sciences and global affairs, the team will work with residents in Lake Charles, Louisiana, to create a new framework for community recovery from natural disasters, educate homeowners on risks and encourage incentives to make necessary upgrades to homes.
But that’s just the beginning. Kijewski-Correa is also the co-principal investigator on a project that will simulate the combined effects of a major hurricane’s force on full-scale structures for the first time.
A summary of Kijewski-Correa’s work in these areas was recently released. Read on for more on current issues with building code regulations, the need for market-based incentives and the detailed planning that goes into creating the nation’s first simulator for combined wind and wave effects.
How will this research help homeowners in the long run?
Coastal homeowners live at great risk right now. Local building codes do not fully protect against damaging hurricanes, creating losses for your home. So, if you want a home you can come back to after the hurricane, you actually have to invest beyond what the building code requires. The first and most important step is helping homeowners understand how to make those choices, and more importantly, how to incentivize them to make those choices. That’s where a lot of the big challenges currently lie.
People don’t realize their local building code doesn’t protect them. Even when they do, many people have a hard time making the difficult decision to invest upfront in protections for an uncertain future hurricane. There’s a lot of incentivization that has to happen in the regulatory and market systems to make this work, whether that’s insurance credits, tax credits or perks of different kinds, including increased valuation of a hurricane-resistant property. That’s what we’ve seen as being the biggest potential incentive — that the real estate appraisal of your home reflects mitigation investments.
A lot of this is seeing what it’s going to take to shift American culture away from reacting to disasters by building back better, and toward proactively building better before being hit by the next hurricane. Because right now, the mounting losses in our coastal communities has bankrupted our insurance systems. We actually can’t keep doing this. It’s not sustainable
The goal of this research is to look at an area that’s getting hit hardest and figure out how to get homeowners to buy into the idea of preparing — because climate change is here. It’s now and the effects are acute. We need to shift out of insurance culture, the culture of waiting for FEMA to come. If homeowners aren’t ready, they’re going to end up out in the cold, literally.
In the last two years, we’ve set records for the number of billion-dollar loss events — a single hurricane, flood or wildfire causing more than a billion dollars in losses. There were a record $22 billion loss events last year. It’s a sobering picture of how the whole country is getting ravaged. We’ve got to get a lot more proactive. Our work has shown that we’ve created a culture of safety netting to manage the symptoms. We’re not really addressing the problem.
Do coastal homeowners know what kind of structural enhancements they need to make to protect against stronger, more intensified climate events?
They don’t. Our research has already shown there are multiple flaws in our national strategy.
The first is the regulatory system. Building codes give a false impression that you’re safe just because you’re built to code. There are two problems with that. First, a building code has to be adopted to be binding and effective. Currently, eight of our coastal states don’t adopt or enforce a building code statewide. So, when you have eight of the 13 states most in harm’s way without a binding statewide building code, that’s a problem.
Approximately every four years, engineers like myself consult on a new set of national building codes — but states have to adopt them. Even the states that do adopt them, like North Carolina, adopt them usually two cycles late — so eight years later. Climate is changing faster than that. By then, those codes are already out of date and homeowners are again at risk.
The second issue that I think most Americans don’t realize is building codes are designed for what is called “life safety.” If your home is in the path of one of these events, that’s why residents are evacuated — we don’t let you stay in your house because we know it’s going to take heavy damage and we are hoping you get out alive. This philosophy created a building code that’s more affordable, but allows major losses. What does it mean that your house passed inspection and was to code? Americans think “OK, I’m built to code,” but that code was set at a threshold that only gets you out alive. What did that code actually give you? No one tells you. Such a code allows not having a place to come home to, and I think most Americans don’t know that. I thought about that as a homeowner myself. The process is too sanitized and lacks transparency regarding the risks we take when we purchase property.
The third issue is building codes only apply to new construction. So even if all 50 states comply, the building inventory in America turns over very slowly. With the current housing deficit, less than 10 percent of buildings in the country are built in a given year. That means 90 percent are outdated. It would take 10 years of everything naturally falling apart and being replaced and cycled out before we would even see change. And there are buildings much older than 10 years on the market. We don’t tear them down on a 10-year cycle, and we don’t have mandatory incentives big enough to force retrofitting of existing buildings to the latest codes.
How realistic is mandatory retrofitting or mandatory building code adoption?
The reality is we cannot get the political will to make sweeping regulatory changes. That’s why we recently focused on market-based incentives, which our research in North Carolina has proven to be viable — and that’s one of the things we’re now exploring in Louisiana.
We’re also focusing on risk communications and incentives messaging. What are states doing to get the word out? What incentives are states putting in place? Are there insurance and/or tax credits for building a safer home? More importantly, does the real estate market advertise and value a safer home? We found the most positive driver of behavior change in North Carolina so far is for people to believe improvements will be valued in the market. They’re investing because they see that as something that will be valued when they sell the house in five years, just like a granite countertop — it’s an investment that will pay returns.
The problem is the market only rewards investments like that at a modest rate. We’re seeing a 1 percent increase in market value for that investment. We’d like to see it treated like when you put in a nice kitchen that is advertised on Zillow. That the first thing that the real estate agent says is this house is hurricane resilient and that adds $50,000 to the market value. We need to push the industry that way, similar to what we do with credits for green building. This is all doable within the real estate industry — but we need the evidence to say that if we do all these things, people will start acting differently, which is where our research comes in. We’re trying to connect with the real estate industry to show the data indicate people will buy houses with these features, and it does a greater good to build safer communities. We hope the real estate industry will start promoting this, and we are working with the Fitzgerald Institute for Real Estate here at Notre Dame to say, “OK, if the laws aren’t going to change at the top, can we drive change in the market at the bottom?”
Does your research address the needs of underserved communities?
We selected Lake Charles, Louisiana, because it’s a very underserved community that took a direct hit from Hurricane Laura. Demographically, it’s much more diverse than the North Carolina communities where we conducted previous studies with respect to both race as well as income. We don’t have the data on these communities to know if they are even movable in their beliefs about the acute threats of climate change.
One aspect of our study looks at whether families even have the bandwidth — not just financially but as well as in terms of time, energy and initiative — to consider these major retrofits or upgrades to their home. If families don’t have the bandwidth, then the messaging and the incentives will mean nothing — and for poor families, we hypothesize that’s going to be an issue.
In doing a recovery scenario for the first time in our research, we will be talking with people who have to rebuild because their house has been damaged or who have had a major wake-up call. We’re engaging people that were hit, or what are called “near misses,” meaning they were very close to being hit.
The idea here is can we couple what’s naturally happening with messaging on rebuilding — so when FEMA, state-level support and home insurers come in after these events, we can get homeowners to make better choices or, again, subsidize, for example, some of the upgrades that are costlier for low-income families. Those families would then have the ability to make their limited dollars go further. There’s a lot of opportunity in a recovery cycle to use that kind of infusion of capital to build back better. Right now, we find that most communities build back the same, because the messaging doesn’t come in time to tell them what to do differently.
Our research through the Structural Extreme Events Reconnaissance (StEER) Network analyzes what went wrong, the damage experienced and how we can use that information to inform messaging in time for the cycle of rebuilding. What incentives might move homeowners to act? If you get the right messages out with the right incentives, then what happens?
This includes helping FEMA understand they should try to reach families that experience what we call a “near miss.” They’ve watched their neighbor lose their whole house. Might you be more primed to messaging and to making those little investments that could improve the resilience of your home?
It’s a chance to change behavior in time for the next hurricane.
So, no one is currently reaching out to “near miss” homeowners and advising them on resilience upgrades to protect their homes for the next hurricane?
Right. There’s general messaging they might hear or see on the news, but in terms of targeted outreach, we’re trying help FEMA and other federal and state partners to capitalize on these teachable moments. Our data will show whether homeowners are actually movable and whether their opinions have been swayed by watching their neighbors’ homes get gutted.
The data we collected in North Carolina tells us that homeowners there believe the climate is changing. They believe that hurricanes are getting stronger. They even believe their house will be hit. But they don’t believe it’ll be damaged significantly. They think even if it is hit, they will be OK. So, we’re wondering … what is the wake-up call to get humans to change behavior?
What have you observed from your experience of doing this research over the years?
There are a lot of good technological advances that die in the last mile because we don’t understand how humans are going to accept or reject that idea. As an engineer, I was really frustrated. We have building codes, and no one adopts them. What is going on? I’ve become increasingly interested in what goes wrong in technology transfer. If we, as engineers, knew upfront what the barriers are, we might approach our research very differently, knowing the constraints and what it takes to sway humans.
If I learn the mitigation investments a family might actually be interested in making, then we know we can stop wasting time on other interventions. Let’s figure out how to make what homeowners are willing to do as easy and as cheap as possible.
A lot of this work that I’ve gotten into is understanding why homeowners aren’t following all this great knowledge engineers are pumping out, the barriers to adoption and the mindset of the stakeholder group at day zero — to understand the problems we should be solving.
Can the study be adopted for other climate events and disasters?
Absolutely. This research is about creating a novel, interdisciplinary approach that can be scaled up. We will be able to do so much more comparative work. Because Texas, compared to Louisiana, will have a different set of norms, different experiences, different regulatory and legal constructs that influence the way people think. We need to study human decision making across the Gulf coast and up the Atlantic seaboard by replicating this going forward.
Kijewski-Correa is co-principal investigator on a $12.8 million project to design a state-of-the-art hurricane simulator. The project is being led by Florida International University and is funded by the National Science Foundation.
Why design this new hurricane simulator?
We are going to be able to put a full-scale house in this simulator and destroy it in a Category Five storm under the combined effects of wind and waves for the first time. We want to push the physical hardware to keep up with where the climate is taking us. We’ve already seen hurricanes that are off the scale. We know that we need to get above the testing capacity of the current facilities here in the United States, in intensity as well as the size of the facility.
We’ll be able to show officials, regulators and stakeholders a video of that test or bring them in to see it for themselves. So, when it comes to convincing building code officials in Calcasieu Parish, Louisiana, for example, that we need to make specific changes to the code, they will see why.
It’s going to change everything.
When we show them the damage via the simulator we can say, this is how vulnerable current practices are, and even more importantly, look at how a home with our new mitigation measures performs in comparison.
What is Notre Dame’s role in designing this simulator?
Notre Dame is part of the leadership team trying to do something that’s never been done before. It’s going to be the first time we are able to simulate a real hurricane in a facility with the water and wind going at once.
We normally approach simulating damage one of three ways. First, we might do a little experiment in a smaller facility, like our current ones in the U.S. where we may put a little house in a big tunnel. But those don’t capture the physics properly due to the small scale of the model.
The second approach is building advanced computer models. But if they’re not calibrated in a way that replicates real life — these models have their own limitations — ultimately, these models must be validated against and calibrated to real-life conditions.
Then we have what I do: field observations. We measure these phenomena and the impact to communities. What you get there is like the snapshot at the end — the before and the after. We’re not there when it’s happening to see what broke off when, how that may have destroyed something else or damaged the next house. We come in and see the pile of chaos, and we document it. So while it is the most realistic, we cannot control this natural laboratory and observe it throughout the storm.
With this project, we want to bring those three different approaches — in the field, simulating storms computationally, running experiments — together for the first time ever.
Once we have calibrated those computational models against experiments in the facility to recreate the conditions for our field observations, we can then use those models to run larger simulations or other scenarios in a cost-effective way. For example, after we test one house, we can reliably build out models for a community of 30 or even 30,000 houses in a computational world — meaning we can simulate the whole community getting hit and explore the return on different mitigation investments. This is only possible once I’ve calibrated the model with a large-scale experiment for the one house, making me confident with replication.
In this case, we’re taking the real measurements of the hurricane wind and waves in the field and we’re using that to drive the machinery in the experiment. We’ll recreate the real conditions on the ground, recreate the damage. When we do that, I could take the data we collected from Hurricane Dorian and recreate Dorian in our simulator with a physical experiment. Then I’ll be able to calibrate a computational model to scale it up over, say, Marsh Harbour in the Bahamas. We can recreate what happened and help the Bahamian government run scenarios to understand how this could be prevented in the future.
That only happens by bringing those three things together for the first time, so that the data is connected, rather than siloed, and Notre Dame has shown leadership in breaking down those silos, which is why we are one of the institutions guiding the facility design.
And there’s nothing like this available in the U.S. right now?
There’s a large facility in South Carolina, which can fit a full-size house, but it does not include any effects of storm surge and waves. We will be able to simulate the combined effects of these hazards, and at a higher intensity than other large-scale facilities. There are also some facilities that have combined wind and water simulations, but at smaller scales for oceanographic research, so they are not able to do destructive testing on buildings and other civil infrastructure.
With this first grant, we have $12 million for just the design. Our team is visiting these and other facilities to gain an understanding of capabilities and pain points — and even use their facilities to generate some preliminary data — so we can design our facility informed by those insights. We’re already building computational models validated against the data they provide us to explore what we think this facility will look like, and how it will work. So instead of designing blind, we’re simulating how it’s going to perform informed by data from existing facilities.
You have to design the physics of the environment to be faithful to nature but realistic for what you can control in a closed facility. We also plan to build a prototype, not to full scale, but at smaller scales by retrofitting some of these existing facilities to get the fans pushing wind at high speed over the water. We want a thoughtful design that ensures the mechanics are working and we’re not making a bad footprint on the environment by consuming lots of unnecessary water and power.
With that comes getting all the field data integrated, building the computational models and the cyber infrastructure that will take the data out of the experiment and create these beautiful visualizations of projected impacts over whole communities. That’s why such a large team is required, including those who’ve built similar facilities, those with fieldwork and computational model expertise. Part of what we’re doing is transforming how we conduct research and develop a future workforce ready to tackle climate change.
We’re thinking about how to teach coastal and wind engineers to conduct research together and train students together. Convergence is a theme — methodologically and disciplinarily bringing together not just coastal and wind engineers, but also social scientists and policy experts. And we’re going to bring in coastal communities from day one and ask, what kind of work should we do in this facility that would best serve you? What would be the requirements to speed these discoveries into policy? We want to define these upfront so we can work on lowering those barriers on day zero during experiments and fast-track that information shaping building codes or zoning policies.
If we bring them in on day one, we’ve got a chance to translate the work into lasting change in these communities.