Featured Research

from universities, journals, and other organizations

Ultrasound Method Diagnoses Stress Before Bridges Crack

Date:
May 14, 1998
Source:
National Institute Of Standards And Technology (NIST)
Summary:
NIST scientists are using ultrasound to measure the change in stresses on pin and hanger assemblies found on bridges. Their goal is to develop a method for assessing the status of these connections.

NIST scientists are using ultrasound to measure the change in stresses on pin and hanger assemblies found on bridges. Their goal is to develop a method for assessing the status of these connections.

In a typical situation, a pin and hanger connection is used to suspend an inner span from an outer support span; it also accommodates thermal expansion. But because the connection is located at the expansion joint, road deicing salts may wash down through the joint and cause corrosion at the pins. If the corrosion is sufficient to lock up the pins, it can cause additional forces on the connection, leading to fatigue cracking and eventual failure.

NIST is experimenting with an ultrasound technique, which has the potential to determine connection stress prior to development of fatigue cracks. To evaluate its method, NIST designed and constructed a pin and hanger simulation facility at its Boulder, Colo., laboratories. Strain gauges were mounted on the hangers, and the strains were measured as load was applied. At the same time, ultrasonic measurements were made at the gauge locations.

Strains were predicted from the ultrasonic data and compared with values measured by the strain gauges. "Overall good agreement was obtained between ultrasonic and strain gauge results," the scientists report.


Story Source:

The above story is based on materials provided by National Institute Of Standards And Technology (NIST). Note: Materials may be edited for content and length.


Cite This Page:

National Institute Of Standards And Technology (NIST). "Ultrasound Method Diagnoses Stress Before Bridges Crack." ScienceDaily. ScienceDaily, 14 May 1998. <www.sciencedaily.com/releases/1998/05/980514080415.htm>.
National Institute Of Standards And Technology (NIST). (1998, May 14). Ultrasound Method Diagnoses Stress Before Bridges Crack. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/1998/05/980514080415.htm
National Institute Of Standards And Technology (NIST). "Ultrasound Method Diagnoses Stress Before Bridges Crack." ScienceDaily. www.sciencedaily.com/releases/1998/05/980514080415.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) 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