Featured Research

from universities, journals, and other organizations

Independent Study Of The I-35W Bridge Collapse Results Parallel NTSB Report

Date:
November 20, 2008
Source:
University of Minnesota
Summary:
Preliminary results of the University of Minnesota's independent academic study of the I-35W bridge collapse suggest that lack of robustness in the bridge's original design, additional load from bridge improvements over the years, weight from construction materials and stresses induced by temperature changes contributed to the collapse of the I-35W bridge on Aug. 1, 2007.

The Interstate 35W bridge collapse on the Mississippi River in Minneapolis, Minnesota.
Credit: iStockphoto/Lawrence Sawyer

Preliminary results of the University of Minnesota's independent academic study of the I-35W bridge collapse suggest that lack of robustness in the bridge's original design, additional load from bridge improvements over the years, weight from construction materials and stresses induced by temperature changes contributed to the collapse of the I-35W bridge on Aug. 1, 2007.

Related Articles


The preliminary results of the yearlong study by civil engineering researchers at the University of Minnesota were released last night to a crowd of about 400 people attending the university's Institute of Technology public lecture "Investing in Infrastructure." The university's findings are consistent with the National Transportation Safety Board's final report summary and the report prepared by Wiss, Janney, Elstner Associates (consultants retained by the Minnesota Department of Transportation).

Highlights of the U of M academic study revealed the following:

  • Some of the gusset plates in the I-35W bridge were not designed to withstand the design loads with an acceptable safety factor.
  • Construction on the bridge in the 1970s and 1990s, including the addition of thicker road beds and guard rails, added significant weight on the bridge. The resulting forces stressed these gusset plates beyond acceptable limits.
  • Additional weight from the construction on Aug. 1, 2007 produced substantial additional forces on the already compromised critical gusset plates. The construction material and equipment most likely initiated the collapse.
  • Temperature changes on the day of the collapse, coupled with partially frozen bridge bearings, may have also introduced additional stresses to the gusset plates.

"The gusset plates at the time of collapse were in a state of instability. In essence the demand on them was equal to their capacity, and they simply gave way," said civil engineering professor and department head Roberto Ballarini.

Researchers involved in the study include civil engineering faculty Roberto Ballarini, Taichiro Okazaki, Ted Galambos and Arturo Schultz.

The researchers conducted their study of the gusset plates in two stages. In the first stage, they created two-dimensional and three-dimensional computer models representing the whole bridge. The second stage consisted of applying the forces calculated in these models to a detailed computer model of the node of the bridge that involved the suspected gusset plate.

"Our computer simulation shows a pattern of very high stresses within the gusset plate that are consistent with the locations and directions of the tears observed in photos of the fractured gussets," Ballarini said.

The researchers plan to publish their final results in an academic research paper within the next six months. The University of Minnesota study was funded by a grant from the National Science Foundation, the university's Center for Transportation Studies and the university's Department of Civil Engineering.


Story Source:

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


Cite This Page:

University of Minnesota. "Independent Study Of The I-35W Bridge Collapse Results Parallel NTSB Report." ScienceDaily. ScienceDaily, 20 November 2008. <www.sciencedaily.com/releases/2008/11/081120122207.htm>.
University of Minnesota. (2008, November 20). Independent Study Of The I-35W Bridge Collapse Results Parallel NTSB Report. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2008/11/081120122207.htm
University of Minnesota. "Independent Study Of The I-35W Bridge Collapse Results Parallel NTSB Report." ScienceDaily. www.sciencedaily.com/releases/2008/11/081120122207.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA's First 3-D Printer In Space Creates Its First Object

NASA's First 3-D Printer In Space Creates Its First Object

Newsy (Nov. 26, 2014) The International Space Station is now using a proof-of-concept 3D printer to test additive printing in a weightless, isolated environment. Video provided by Newsy
Powered by NewsLook.com
Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Blu-Ray Discs Getting Second Run As Solar Panels

Blu-Ray Discs Getting Second Run As Solar Panels

Newsy (Nov. 26, 2014) Researchers at Northwestern University are repurposing Blu-ray movies for better solar panel technology thanks to the discs' internal structures. Video provided by Newsy
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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