Hurricane simulator ‘Cat 6’ with 200 mph winds

Howling Category 6 hurricane winds are accelerating to 200 mph in Miami, pounding a two-story wood-frame home mercilessly until the roof rips and slamming windows explode.

And a towering 20-foot storm surge spawns pounding waves, flooding the structure and pushing it off its foundation like a doomed dollhouse.

Looks like a scene from a sci-fi disaster movie.

But with real-world Atlantic hurricanes pushing the limits of Hurricane Saffir-Simpson’s wind scale, Florida International University researchers envision a future mega-wind-water simulator that tests how components of the building under Category 6 conditions.

The FIU’s Extreme Events Institute already operates the 157-mph Wall of Wind hurricane simulator, where experimental results have been applied to the Florida Building Code. Today, the school is leading a $12.8 million partnership with the National Science Foundation to design a larger national test facility capable of generating 200 mph winds.

In destructive tandem, this Cat 6 project will incorporate a water basin that can produce up to 20 feet of storm surge.

“We used the 200 mph mark because there are more and more events lately that they call stronger than Cat 5,” said Ioannis Zisis, co-director of the FIU Wind Engineering Research Laboratory. .

“It’s a very ambitious project in terms of combining different hazards. So we want to do the wind, but we also want to add the storm surge, the water component,” Zisis said.

“So it’s a very complex project, a very complex installation – which is also going to be very expensive,” he said.

CRF’s academic partners on the project: University of Florida, Oregon State University, Stanford University, University of Notre Dame, Georgia Institute of Technology, University of Illinois at Urbana-Champaign, Colorado State University and Wayne State University. Aerolab, a Maryland wind tunnel company, is the industry’s premier partner.

Design work began in January on the future simulator, technically named NICHE (National Full-Scale Testing Infrastructure for Community Hardening in Extreme Wind, Surge, and Wave Events).

Zisis said the researchers will spend the next four years designing the massive facility – and it’s “essential” they make a series of key decisions in the first six months. Other construction details, such as funding sources, remain unknown.

Should we create a category 6 hurricane?

Richard Olson is director of the CRF’s Extreme Events Institute. In a FLORIDA TODAY 2019 guest column, he pushed for the creation of a new Category 6 hurricane – with fearsome sustained wind speeds of 180 mph or more – at the top of the Saffir-Simpson wind scale. Five-level Hurricane Wind Scale.

Olson pointed to historic storms such as the 1935 “Great Labor Day Hurricane” in the Florida Keys (sustained winds of 185 mph), Hurricane Allen in 1980 (190 mph), Hurricane Wilma in 2005 (185 mph) , Hurricane Irma in 2017 (180 mph) and Hurricane Dorian in 2018 (185 mph).

“Opening a discussion on at least one category 6 for storms in the Atlantic basin presents a certain urgency. Climate change scientists are making the case for an increasing number of more intense storms in the coming decades,” Olson said in his 2019 column.

“That is, storms with sustained wind speeds of 180 mph should no longer be considered extremely rare,” Olson said.

Federal Emergency Management Agency Administrator Deanne Criswell touted the FIU project during a commencement address at the National Hurricane Center on April 13 in Orlando.

“What if we could simulate a Category 6 hurricane? Criswell asked the audience.

“This kind of cutting-edge research, this kind of testing capacity, is exactly what we need to deal with the country’s ever-changing risks. To help us adapt to future conditions. And to help us protect life and property,” she said.

Criswell said FEMA projects U.S. communities that adopt modern building codes will avoid paying $132 billion in storm damage by 2040 — but 65% of counties, cities and towns have not adopted. modern building codes.

CRF 157 mph wind wall

The CRF Wind Wall is a warehouse-like facility that can create Category 5 hurricane conditions with winds of up to 157 mph. Researchers blow up test structures equipped with sensors – such as simulated small houses, roofing materials, windows, traffic lights and solar panels – and create three-dimensional computer models measuring wind forces.

The 8,400 horsepower wind wall is powered by a dozen yellow circular fans, each measuring 6 feet in diameter and weighing 15,000 pounds.

The water outlets also mimic cascading rainfall amounts of up to 8 to 9 inches per hour.

Last year, the NSF awarded CRF a $5.62 million grant to continue scientific research on the wind wall through September 2025. However, unlike the wind wall, Zisis said the future category 6 hurricane simulator will be large enough to accommodate normal sized homes.

“We’re looking at putting a two-story building in front of the fans, on a hub,” Zisis said.

“Right now, we can test a smaller structure. We can test building components, solar panels, things like that. But the actual structure that we can put up in front of the wind wall looks like a 10 x 10 x 10 cube,” he said.

“Over the past 30, 40 years, most of the things we have in building code and wind tunnels have come from small-scale studies. And they are very, very useful. Very scientific, and they are very important. But when we test on a large scale, we learn even more,” he said.

“Right now, we are focusing more on component testing in the Windwall as we are limited by size. We cannot see how the wind load is transferred from the exterior of the building to the foundation. It’s something we’re looking at doing with a new facility,” he said.

So how big should FIU’s Cat 6 simulator be? The Miami New Times reported that it could be comparable in size to a small football stadium, while The Washington Post reported that the wave pool could be 200 feet long.

No one knows at this early stage, Zisis said. During the $12.8 million design effort, Zsis said the researchers would build a smaller-scale simulator prototype at CRF to test and validate their hypotheses.

“The small-scale replica of this huge facility will be more or less of a similar size to the wind wall,” he said.

FEMA: Expect extreme weather events

During his speech at the National Hurricane Conference, Criswell said the United Nations Climate Science Panel fears that unless global greenhouse gas emissions peak by 2025 and are reduced by 43% by 2030, the world is likely to experience extreme weather events.

“Now, does this information make us fall back into our seats? Perhaps. But I encourage all of us in this room to embrace this information and not take it as alarmist,” Criswell told the audience.

“We have the best climate scientists in the world working hand in hand, nation to nation, to arm us with the best information and data available to help us save lives and protect property. So we need to take advantage of this data and take action,” she said.

“Let us use it to inspire collective change towards a future-oriented mindset at all levels of government and in all of our communities nationwide. Let’s use it to anticipate, plan and mitigate risks that are 10, 20, 30 years in the future,” she said.

Jim Bell is director of operations for the National Storm Shelter Association. A former resident of Fort Lauderdale, he was president of the Gold Coast chapter of the Door and Hardware Institute when he served on a committee that helped strengthen Florida’s building code after Hurricane Andrew hit in 1992. .

“The most intriguing part is the storm surge. Because it’s even more violent than the winds,” Bell said of FIU’s upcoming Cat 6 simulator.

“When we talk about the wind speed they’re looking at, you’re going to have to do more with windows and doors and such. Because once the wind gets inside the building, the building gets pressurized — and it blows the roof off or blows out the windows,” Bell said.

“As the pressure builds, it looks for another place to push. That’s what creates the damage, the explosion effect,” he said.

Hurricane Saffir-Simpson Wind Scale

Wind-scale structural damage details from Hurricane Saffir-Simpson, according to the National Hurricane Center:

Category 1: 74 to 95 mph. “Well-built frame homes could have damage to the roof, shingles, vinyl siding, and gutters. Large tree branches break and trees with shallow roots can be knocked over. Extensive damage to power lines and poles will likely result in power outages that could last anywhere from a few to several days.

Category 2: 96 to 110 mph. “Well-built frame homes could suffer significant roof and siding damage. Many trees with shallow roots will be broken or uprooted and block many roads. Near total loss of power is expected with outages that could last from several days to several weeks.

Category 3: 111 to 129 mph. “Well-constructed frame homes can experience significant damage or removal of roof decking and gables. Many trees will be snapped or uprooted, blocking many roads. Electricity and water will be unavailable for several days to several weeks after the storm has passed.

Category 4: 130 to 156 mph. “Well-constructed frame homes can suffer severe damage with the loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and utility poles knocked down. Fallen trees and utility poles will isolate residential areas. Power outages will last for weeks or even months. Most of the area will be uninhabitable for weeks or months.

Category 5: 157 mph or more. “A high percentage of frame houses will be destroyed, with total roof failure and wall collapse. Fallen trees and utility poles will isolate residential areas. Power outages will last for weeks or even months. of the area will be uninhabitable for weeks or months.