CU Boulder partners with Notre Dame to improve housing resilience

After the 2023 Lahaina Fire devastated Maui's historic town, killing 102 people and destroying more than 2,200 structures, two longtime friends teamed up to study housing resilience-an idea they first discussed in graduate school.

Abbie Liel, a professor of civil, environmental and architectural engineering at the University of Colorado Boulder, and Susan Ostermann, an assistant professor of global affairs at the University of Notre Dame, are exploring solutions for building homes that can withstand disasters like hurricanes and fires, each approaching the issue from different perspectives.

Liel, a structural engineer, brings expertise in buildings and their hazard and climate-related vulnerabilities. Ostermann, a political scientist and attorney, studies how to achieve desired outcomes, such as resilient housing, through a combination of regulatory and non-regulatory means. Both are exploring how their research findings can inform policy recommendations.

"Everybody wants safe, resilient housing," Liel says. "Many communities in America have building codes to support that. But, in some places, it doesn't work very well."

New beginnings
Their idea to collaborate fully emerged during the pandemic when Liel and Ostermann discussed how regulations impact the building industry. The two saw an opportunity to combine Liel's engineering expertise with Ostermann's background in political science and law, which led to an NSF proposal that outlined their collaborative vision.

Their Maui study is part of a larger National Science Foundation-funded project on housing resilience that also includes Alaska and Puerto Rico. Alaska experienced an earthquake in 2018 and several high-wind events that resulted in significant damage, while Puerto Rico was struck by Hurricanes Irma and Maria in 2017 and earthquakes in 2014 and 2020.

"In Alaska, regulations don't work very well because there's strong pushback against them," Liel says. "There's no resistance to safe, resilient housing. But there's a strong resistance to a system that says you must do it, and you must do it in a specific way."

The two are exploring which aspects of regulations are effective. Despite extensive building regulations, surprisingly little research has been done on their impact, Liel says.

One of the problems Liel identifies is the complexity of building codes and regulations.

"I believe in regulations as a mechanism. But they're this," she says, pulling out several heavy, thick regulation books from her shelf. "And there's a bunch of other books that go with them. Regulations support the goals of safe, resilient housing, but they can also get in the way. We need to understand how culture and local building practices interact with regulatory processes and determine what needs to be tweaked about that system to support resilient housing.

"Builders want to provide safe, resilient houses. However, regulations frequently change. Do they really need three-inch nail spacing or would six-inch spacing be enough? Because using six-inch spacing might be much easier to construct."

Different but same
Puerto Rico, Maui and Alaska each have distinct local building practices but share similarities, Liel notes. All three locations are remote and expansive and have significant indigenous populations. Residents in all three areas recognize the uniqueness of their communities and face challenges distinct from more centrally located areas.

"Understanding the differences and similarities between the three locations helps us understand what's going on across America," Liel says.

Maui faces distinct hazards, such as wildfire risk, in addition to high winds and earthquakes. Hawaii's regulatory context, compared to Alaska, shows a more general acceptance of building codes and regulations. While Maui residents may feel these regulations don't always serve them well, the emphasis is on improving them rather than dismissing them entirely.

"I'm generalizing from many interviews, but it seems that with a more effective regulatory process-or even non-regulatory approaches- we could achieve better outcomes, enhance hazard management and gain fresh perspectives," Liel says.

Strengthening research through collaboration
Essential to the project is a team of student research assistants, including three CU Boulder civil engineering graduate students and five Notre Dame undergraduates representing a variety of majors ranging from global affairs to psychology to mechanical engineering.

As part of the three-area study, the team identified key building safety characteristics crucial for protection from windstorms and earthquakes, then compared how homes in different areas varied in terms of walls, roof shapes, number of stories and the presence of large garages.

Brianna Clark, a CU Boulder master's student who graduated in 2024, worked on the Alaska portion of the project, using drone imaging to assess the impact of regulations on construction. She compared areas with plan reviews and inspections to those without, to better understand how regulations influence building practices.

Diego Valdivieso, a CU Boulder graduate student from Chile, has been researching ways to support wood frame construction in his home country. In Puerto Rico, he and others explored the shift from timber to reinforced concrete-a material that increases embodied carbon and presents seismic vulnerabilities though it offers more safety in hurricanes. Their research investigates how timber could still serve as a viable, hurricane-resistant building option.

"Residents want to avoid roofs blowing off during storms, and it is preventable," Liel says. "Our goal is to promote knowledge on building hurricane-resistant roofs and support safer construction practices."

Through regular meetings, CU Boulder and Notre Dame students connect, and Liel and Ostermann engage with students from both universities. For example, Ostermann was on Clark's master's thesis committee.

"The students support each other and share their perspectives, creating a rich learning environment," Liel says. "Instead of working in isolation and combining efforts later, we collaborate on all aspects of the project, ensuring an interdisciplinary approach.

"We learned a lot from past disasters like the Marshall Fire, but my dream is to gain this knowledge before disasters strike. As we build communities, it's crucial to understand not just safe construction, but also the processes supporting it. We shouldn't wait for the next disaster to figure out how to ensure safety and resilience."

One example is in Alaska, where the team is exploring how to provide real estate buyers with information to assess a property's resilience before purchase.

"The 2018 earthquake near Anchorage, showed that some homes withstood the event well, while others did not. Regulations are meant to set a baseline for safety and quality, but in areas where they are absent or poorly enforced, buyers may struggle to gauge a property's true condition. We're exploring ways to improve transparency in the home-buying process to address this."

Next steps
The team will analyze more than 100 interviews completed in Puerto Rico, Alaska and Hawaii, for a comparative study. Next summer, the researchers plan to explore interventions that address the challenges they've identified. In Alaska, for example, they might focus on improving building information disclosure, while in Puerto Rico, the team will be exploring how providing information about hurricane straps-how they connect roofs to walls and their availability-could encourage their use.

"This project highlights the power of interdisciplinary collaboration," Liel says. "Everyone listens and is open to learning from each other."

The University of Notre Dame contributed to this report.

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