A research team, consisting of academic researchers from multiple universities and professional engineers, received a National Science Foundation RAPID Response Grant for Exploratory Research to investigate and gather data about the damage to, and performance of, wood frame structures in the affected areas due to strong winds. The team primarily looked at residential and multi-family apartments, but also reviewed some steel and masonry buildings.
The research team inspected the 5.9-mile affected tornado path in Tuscaloosa on May 2-5 to analyze wood-frame structures that were damaged by wind and windblown debris. Following clearance from FEMA’s Engineering Division, the team inspected more than 150 structures in extensive detail. Collecting more than 3,000 photos of single family homes (one- and two-story) and apartment complexes, the team determined the EF-Scale rating in relation to damage for each structure in order to develop a swath, or contour, map showing the localized intensity of the tornado.
“Through this multi-university and industry collaboration, we can provide valuable research to help design safer homes,” said Dr. John van de Lindt, UA’s lead investigator and professor of civil, construction and environmental engineering. “It is very difficult to investigate the load characteristics of buildings within a tornado path. Developing something we call a dual objective-based design method to better mitigate the effect of tornadoes will reduce damage and save lives.”
“Light-frame wood structures will not be able to withstand the EF4 and EF5 forces in the direct center path of a storm, but the areas on the edges of a storm could see dramatic improvements in safety and overall structure through better engineering design and construction practices,” said Dr. Andrew Graettinger, UA associate professor of civil, construction and environmental engineering. “The results of this study could impact many areas throughout the country by hopefully reducing the amount of damage sustained by the lower wind speeds seen on the edges of tornados.”
Other key conclusions and recommendations from the study include:
• Light-frame wood buildings do not, and will not, have the ability to resist EF4 or EF5 tornadoes. The level of damage to light-frame buildings at lower wind speeds is not acceptable and can be reduced through new engineering design and construction practices. A systematic study needs to be conducted that focuses on the optimal threshold tornado wind speed for which engineers should be designing, likely an effort to provide a uniform-risk design.
• Virtually all buildings in the path of a strong tornado, even along the outer edges where wind speeds are lower, are irreparable based on current design and construction practices. This provides incentive and an opportunity for tornado-resistant design and construction practices which currently do not exist.
• Vertical load paths were not adequate, regardless of the age of the residential structure. Load paths appeared to be better provided on multi-family buildings. The current understanding of tornado loading on structures is not comprehensive or even comparable to that for strong straight line winds because of the high level of turbulence and debris in tornadoes, and the vertical uplift forces in a vortex can be as much as 3.2 times larger than straight wind counterparts.
• Need acceptable and implementable approaches in design and construction to realize damage reduction. Design and retrofit measures should be developed to reduce structural and component damage up to the threshold wind speed. Implementing hurricane region construction practices and products in tornado-prone regions is an excellent starting point, but may not necessarily be an end solution.
• Interior closets and bathrooms provide shelter at lower wind speeds on the edges of the tornado, but they were no guarantee of survival. The concept of a “safe spot” should still be taught, but a safe spot is not a substitute for a safe room or tornado shelter. For wind speeds exceeding the threshold, the alternatives of a shelter or safe room can provide life safety to building occupants.
The research team received the grant because of The University of Alabama’s location to the proximity of the affected areas. The National Science Foundation recognized the urgency with the grant request because this type of data is perishable in that once debris removal begins there is no way to analyze the performance of the wood structures. The grant is being provided to The University of Florida to work in close collaboration with UA and other researchers.
The team consisted of the following researchers:• Dr. David O. Prevatt, principal investigator of the project, assistant professor of civil and coastal engineering, The University of Florida
• Samuel Hensen, branch engineering and technical manager, Simpson Strong-Tie Co.
In 1837, The University of Alabama became one of the first five universities in the nation to offer engineering classes. Today, UA’s fully accredited College of Engineering has nearly 3,100 students and more than 100 faculty. In the last eight years, students in the College have been named USA Today All-USA College Academic Team members, Goldwater scholars, Hollings scholars and Portz scholars.
The University of Alabama, a student-centered research university, is experiencing significant growth in both enrollment and academic quality. This growth, which is positively impacting the campus and the state's economy, is in keeping with UA's vision to be the university of choice for the best and brightest students. UA, the state's flagship university, is an academic community united in its commitment to enhancing the quality of life for all Alabamians.
Mary Wymer | Newswise Science News
New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)
Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences