Featured Research

from universities, journals, and other organizations

Increase in tornado, hurricane damage brings call for more stringent building standards

Date:
August 8, 2011
Source:
Oregon State University
Summary:
Researchers have examined some of last spring's massive tornado damage and conclude in a new report that more intensive engineering design and more rigorous, localized construction and inspection standards are needed to reduce property damage and loss of life.

Researchers from a team funded by the National Science Foundation have examined some of last spring's massive tornado damage and conclude in a new report that more intensive engineering design and more rigorous, localized construction and inspection standards are needed to reduce property damage and loss of life.

As one of the nation's most destructive tornado seasons in history begins to wane, and hurricane season approaches its peak, experts are working to determine if old, tried-and-true approaches to residential and small building construction are still adequate, or if it's time to revisit these issues.

"Modern building codes are not what we would call inadequate, but they are kind of a bare minimum," said Rakesh Gupta, a professor of wood engineering and mechanics at Oregon State University, and one of the members of the NSF team that traveled to such sites as Tuscaloosa, Ala., and Joplin, Mo. -- where a massive EF5 tornado in May killed more than 150 people and caused damage approaching $3 billion.

"Beyond that, in the actual construction process, buildings are often not built precisely to codes, due to inadequate construction work or code enforcement," he said. "We can do better. The damage didn't have to be as bad as it was. We can design and build structures more rigorously that could withstand wind forces up to 140-150 miles per hour, which would help them better resist both tornadoes and hurricanes."

In their research, the scientists and engineers found that even in the most catastrophic tornadoes, the path exposed to the most extreme winds is very narrow. In the Joplin example, buildings less than one-half mile away probably faced winds in the 130 mph range, which often destroyed them because they lacked appropriate fasteners, tie-downs, connectors, or adequate number of sheathing nails.

"Another thing we need to consider more in our building practices is the local risks and situation," said Arijit Sinha, an OSU professor in the Department of Wood Science and Engineering.

"Just as cities like San Francisco adapt their building codes to consider earthquake risks, many other towns and cities across the nation could be creating local codes to reflect their specific risks from hurricanes, tornadoes, high winds or other concerns," Sinha said. "A national building code may be convenient, but it isn't always the best for every single town in the country."

Among the findings of the new report:

  • It's not possible to economically design wood-frame structures that could resist damage from the highest winds in extreme tornado events, such as EF4 or EF5, but irreparable damage from lesser winds could and should be reduced.
  • Tornadoes and hurricanes apply different types of forces to buildings, and what will adequately protect from one type of storm event isn't identical to the other. Implementing hurricane-region construction practices in a tornado-prone region is a good start, but not an end solution.
  • Vertical uplift, one of the special risks from tornadoes, is often not planned for in traditional construction approaches.
  • Interior closets and bathrooms can provide some protection at lower wind speeds, but more consideration should be given to construction of "safe rooms" that can save lives in major events.

Cost will always be an issue in either new construction or retrofitting of existing structures to better resist these violent storms, the researchers said, but in new construction some of the costs are fairly modest. Thicker plywood sheathing, closer stud spacing such as 12 inches on center, tighter nailing schedules, and more consistent use of inexpensive metal connectors such as "hurricane ties" and anchor bolts could accomplish much to improve safety and reduce damage, Gupta said.

Retrofitting of existing homes is much more costly, but still something many homeowners should consider, he said. And although tornadoes and hurricanes have different types of impacts on buildings, the wind speeds of a moderate tornado and major hurricane are similar.

Even where cities and towns don't have more stringent building codes, Sinha said, individuals can and probably should have their blueprints or structures reviewed by licensed engineers to plan adequately for damage from hurricanes, tornadoes, earthquakes or other extreme forces.

For reasons that are not clear, 2011 has been one of the most destructive tornado years in history, even in regions of the Midwest and South that experience these storms with regularity.

One of the largest outbreaks of severe weather in U.S. history occurred on April 27, including a tornado that hit Tuscaloosa County in Alabama, destroying or severely damaging 4,700 homes. The new report was based on lessons learned from that event.

The report was done by a study team supported by the National Science Foundation and the International Associations for Wind Engineering that included researchers from OSU, the University of Florida, University of Alabama, Applied Technology Council, South Dakota State University, and private industry.

Report and damage map.


Story Source:

The above story is based on materials provided by Oregon State University. Note: Materials may be edited for content and length.


Cite This Page:

Oregon State University. "Increase in tornado, hurricane damage brings call for more stringent building standards." ScienceDaily. ScienceDaily, 8 August 2011. <www.sciencedaily.com/releases/2011/08/110808124248.htm>.
Oregon State University. (2011, August 8). Increase in tornado, hurricane damage brings call for more stringent building standards. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2011/08/110808124248.htm
Oregon State University. "Increase in tornado, hurricane damage brings call for more stringent building standards." ScienceDaily. www.sciencedaily.com/releases/2011/08/110808124248.htm (accessed September 20, 2014).

Share This



More Earth & Climate News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins