Featured Research

from universities, journals, and other organizations

New Penn State Approach Steadies Floors Too Flexible For Comfort

Date:
September 25, 2001
Source:
Penn State
Summary:
A Penn State architectural engineer has developed a less disruptive, more cost-effective, active control approach to steadying floors that move excessively and annoy or frighten people who walk, work, exercise or dance on them.

University Park, Pa. --- A Penn State architectural engineer has developed a less disruptive, more cost-effective, active control approach to steadying floors that move excessively and annoy or frighten people who walk, work, exercise or dance on them.

Dr. Linda M. Hanagan, assistant professor of architectural engineering, says, "People don't think floors should move, and when they do, this motion can be perceived as annoying or even dangerous. This perception of danger can persist, even though no danger is present."

Stiffening or thickening the floors in an existing building to decrease excessive motion is costly and can take months to complete, disrupting the building's occupants, she adds. However, Hanagan's new approach can be more effective than other structural retrofits and often takes less than a week to fix the problem.

Hanagan's approach, for which Penn State recently filed a provisional patent application, uses active control systems installed on the floor or in the ceiling cavity below it to damp the vibrations.

For example, if people are doing the bunny hop, the hop, hop, hop motion can cause a long-span, steel floor to begin to vibrate in response to the up-and-down motion of the dancers. Each time the dancers hop, the regular "beat" can cause the floor's up and down motion to increase. Hanagan says, "This happens because a component of the ‘beat' is in resonance with the natural frequency of the floor."

The researcher's solution is to use strategically placed "smart" counterweights that sense the magnitude of the floor's motion and move to apply opposing forces to damp or diminish the vibrations. The active control system detects when the floor is moving up and down and when to react in the opposite direction to counter the movement.

The Penn State architectural engineer notes that her active floor vibration control system is similar in concept to the tuned mass damper (TMD) approach that is sometimes used to correct floor motion. Both Hanagan's approach and TMD rely on a moving mass to dissipate the energy in the floor system. The advantage of the active system, which uses floor velocity measurements to generate the amount of force needed to damp the floor motion, is that it requires less moving mass to get the same degree of control as a TMD system. One study showed that a TMD system would have to weigh 30 times more than the active control system.

"When TMDs have been ruled out as a repair option because the existing structure can't support the additional weight, the active system could be the only viable option," Hanagan adds.

The active system is cost effective too. "As recently as a few years ago, 20 pounds of force cost about $30,000 to generate. Today, thanks to the improved capabilities of commercially available linear motors, we can generate 500 pounds for about $50,000," she notes. The Penn State researcher is currently working on a non-exclusive basis with a commercial partner to apply her approach. She also measures and assesses floors on a consulting basis. In addition, she conducts research to provide design engineers with better tools to predict vibration behavior and prevent vibration problems before a building is constructed.

Hanagan's early work on active control of floor vibration was supported in part by the National Science Foundation. The active control approach has been described in publications including Experimental Implementation of Active Control to Reduce Annoying Floor Vibrations in the Engineering Journal, fourth quarter issue, 1998. Other publications are noted on Hanagan's website at http://www.engr.psu.edu/www/dept/arc/server/faculty/hanagan.htm


Story Source:

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


Cite This Page:

Penn State. "New Penn State Approach Steadies Floors Too Flexible For Comfort." ScienceDaily. ScienceDaily, 25 September 2001. <www.sciencedaily.com/releases/2001/09/010925071423.htm>.
Penn State. (2001, September 25). New Penn State Approach Steadies Floors Too Flexible For Comfort. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2001/09/010925071423.htm
Penn State. "New Penn State Approach Steadies Floors Too Flexible For Comfort." ScienceDaily. www.sciencedaily.com/releases/2001/09/010925071423.htm (accessed September 1, 2014).

Share This




More Matter & Energy News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
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