Hurricanes just keep growing stronger. Due to increased greenhouse gas emissions, the air is able to hold onto more moisture, and the oceans are warming, creating the perfect storm. A May 2018 study in the Journal of Climate estimates that if Hurricane Ike—which tore apart Galveston, Texas, in 2008—were to occur in the late 21st century, its would be 34 percent wetter, and its winds would be 13 percent stronger.
So, the testing facilities used to research storms’ effects on engineered structures, like homes and bridges, need to keep up. That’s why the U.S. National Science Foundation entered into a $12.8 million agreement with Florida International University’s (FIU) Extreme Events Institute earlier this year to take the school’s existing Wall of Wind facility up a notch.
Even though it’s the only life-size test facility at a United States university capable of simulating a Category 5 hurricane wind speed, the Wall of Wind just isn’t suitable anymore. In four years, the updated facility should be capable of testing wind speeds of up to 320 kilometres per hour, and contain a new water basin to simulate storm surges and waves.
The current Wall of Wind facility uses 12 fans powered at 8,400 horsepower to simulate winds of 250 kilometres per hour. Water jets mix in a wind-driven rain simulation. The curved wall of fans, each as tall as a person, blows toward a large field so engineers can observe how and where structures fail and debris flies.
FIU will team up with eight other academic partners—ranging from the University of Florida and Oregon State University, to Stanford University and the University of Notre Dame—to design the new facility. The long-term goal is to enable hurricane simulations beyond the current Category 5 designation, combining the effects of extreme winds, storm surges, waves, and overland water flows on buildings, water and energy systems, roads, bridges, and other key infrastructure.
“Climate change is fueling more intense and more dangerous storms, and cutting-edge research and testing capabilities are clearly needed to meet the nation’s evolving risks,” Richard Olson, Extreme Events Institute director, says in an FIU news release. “In fact, and because the famous Saffir-Simpson Hurricane Wind Scale only goes to Category 5, internally we call this our ‘Cat 6 project.’”
For a decade already, the Wall of Wind, located in an airplane hangar in Miami, has served as the most powerful testing facility for engineers. But studies show tropical storms have increased in intensity: Hurricane Dorian hit the Bahamas in 2019 with 300-kilometre-per-hour winds, and Hurricane Patricia in 2015 blasted Mexico with 350-kilometre-per-hour winds.
The Wall of Wind testing grounds allow engineers to “probe for weaknesses in construction and design, track failures cascading through a building, and test innovative solutions in close to real-world storm conditions,” according to an FIU news release. Cameras and sensors capture every moment as buildings, roofing materials, and other items fail—or don’t fail.
FIU says ten years of destructive testing research has helped engineers see that wind penetrating a structure’s weakest point can rip it apart in less than a second. And once a building fails, it creates another issue in terms of flying debris. FIU notes the testing has shown how debris from one building—under continuous winds of over 210 kilometres per hour —can take out another building, which in turn can shred another building.
Roofs present the weakest link due to uplift force and the power of a wind swirl “almost like a corkscrew at a building’s edge.” New designs get tested within the Wall of Wind facility, whether with technology designed to diffuse the wind’s power or shapes meant to deflect wind forces. Testing has shown, for example, that rounded edges—instead of sharp corners—reduce wind pressure. Smaller design changes, such as hurricane straps in the roof truss (metal ties that reinforce your roof’s connection to your house), threaded ring shank nails to grasp wood, and hurricane shutters over windows, can all help your home withstand wind’s destructive power.
Computer modeling can only go so far in helping engineers understand the power of 320-kilometre-per-hour winds. An updated Wall of Wind can provide the real-world evidence, however catastrophic the results may be.