Auburn University engineering professor offers expertise on structural integrity of homes in high winds

David Roueche, an assistant professor in the Auburn University Department of Civil Engineering, is an expert in research focusing on the effects of major weather events on communities and damage to the nation’s infrastructure. He specializes in research in the areas of extreme wind loads on low-rise buildings; post-disaster field investigations; performance-based wind engineering; wind resistance of light wood-frame structures; and surge and flood load modeling. Roueche was recently quoted on NPR and in The Wall Street Journal as well as this podcast involving his expertise relating to the March 3 tornadoes that hit Lee County, and below he offers a further Q&A on the topic.

Could you explain the type of research you undertake involving structural damage in weather-induced disasters, and how are you employing that expertise regarding the recent tornadoes in Lee County?

It’s important to remember that weather-induced disasters occur when vulnerable human populations and infrastructure are exposed to naturally occurring weather hazards (e.g., hurricanes, tornadoes). If we can reduce vulnerability before the weather hazard occurs, we can reduce the extent of the disaster and keep people safe. My research primarily focuses on the role buildings play in defining a communities’ vulnerability, and how better engineering can reduce that vulnerability while at the same time maintaining proper balances between other competing interests, such as affordability. My research team studies how wind interacts with buildings and the surrounding terrain through laboratory experiments, numerical simulations, and in the real world through detailed forensic engineering investigations following weather-induced disasters. Since the March 3, 2019 tornadoes, I have been primarily focused on the issue of survivability, seeking to identify the specific factors in buildings that make them vulnerable to injuries and fatalities in extreme events like the EF4 tornado. Ultimately, the goal is to recommend better construction practices and have confidence that they will work and protect lives during nature’s ultimate tests.

When the rebuilding phase begins in the areas hardest hit by the recent tornadoes, what recommendations would you have for replacement structures?

Don’t settle for the building code minimum requirements. For a site-built home, the building code is only intended to keep your life safe in a 115 mph wind event (in non-coastal counties of Alabama). It only costs a few dollars when rebuilding to add metal straps to connections to better tie the structure together, or to use ring-shank nails to fasten the roof deck to the trusses or rafters, or to use engineered wood sheathing (OSB or plywood) instead of insulation board for the walls. These are simple choices that make a huge difference. Look at something like the Fortified® program to help you decide what level of wind resistance you want in your replacement structure. If you are looking to purchase a manufactured home, make sure the installer actually installs the ground anchors. Consider installing the anchorage that would be required for a manufactured home in a coastal Alabama county (typically consists of both vertical and diagonal tiedown straps and more closely spaced anchors). The Manufactured Home Inspection Checklist produced by the Institute of Business and Home Safety (IBHS) is a great resource for knowing what options you have. Don’t let the builder, installer or manufacturer tell you that “increasing the wind resistance doesn’t matter because nothing can survive an EF4 tornado”. Whether the home survives or not, a more wind resistant home will help make sure you survive if you are forced to shelter in your home during a tornado. 

What is the most important thing that homeowners should know in terms of structural integrity and keeping safe during a dangerous storm?

If you were to pick up your home and turn it upside down, would it stay in place? If it’s built properly to resist high winds, it should. Doing so requires a continuous lateral and vertical load path – that’s what we call the chain of building elements (e.g., trusses, wall studs, sheathing, concrete slab) and connections that work together to resist the high forces tornadoes and other windstorms induce. You want every link of that chain to be strong. FEMA, the Fortified® program, and others have many great resources explaining what all is involved in a continuous load path. Depending on the level of wind resistance you choose, it may still be damaged during a direct hit by an EF4 tornado, but it will help protect your life. For ultimate peace of mind, the best option for keeping you safe will always be a storm shelter that is certified as being compliant with the FEMA 320 storm shelter design requirements. There are many different storm shelter manufacturers in Alabama. Check whether they are a member of the National Storm Shelter Association and then check their catalog to see if there are options that are right for you. See the FEMA Recovery Advisory issued after the 2007 tornado outbreak for more information about sheltering options.

The Samuel Ginn College of Engineering recently announced that it is constructing a $22 million Advanced Structural Testing Laboratory. How will this state-of-the-art facility transform how we conduct research and testing to prevent deaths and injuries from natural hazard-induced disaster events? 

The Advanced Structural Testing Laboratory is going to be a huge advancement for Auburn University and the state of Alabama, and the research it will allow us to do will prevent deaths and injuries. Having the capability of conducting highly dynamic experimental testing on full-scale or large-scale structural systems allows us to bring what we see in the real world during our field reconnaissance into the laboratory and test it more accurately. Having a geotechnical chamber available within the Advanced Structural Testing Laboratory also gives us the option to fully explore the interactions between the structure, its foundation, and the ground that supports it. Each of these will help us confirm existing vulnerabilities and develop effective solutions that will protect life and property during future extreme hazard events.