Featured Research

from universities, journals, and other organizations

Engineers simulate large earthquake on curved bridge

Date:
September 28, 2011
Source:
University of Nevada, Reno
Summary:
Six full-size pickup trucks took a wild ride on a 16-foot-high steel bridge when it shook violently in a series of never-before-conducted experiments to investigate the seismic behavior of a curved bridge with vehicles in place. The 145-foot-long, 162-ton steel and concrete bridge was built atop four large, 14-foot by 14-foot, hydraulic shake tables.

Laboratory technician Chad Lyttle makes adjustments to sensor cables in final preparations for earthquake engineering tests at the University of Nevada, Reno's Large-Scale Structures Lab. The first-ever tests on a bridge with truck traffic will help improve design regulations and standards and assure safer bridges during large earthquakes.
Credit: Photo by Mike Wolterbeek, University of Nevada, Reno.

Six full-size pickup trucks took a wild ride on a 16-foot-high steel bridge when it shook violently in a series of never-before-conducted experiments to investigate the seismic behavior of a curved bridge with vehicles in place. The 145-foot-long, 162-ton steel and concrete bridge was built atop four large, 14-foot by 14-foot, hydraulic shake tables in the University of Nevada, Reno's Large-Scale Structures Earthquake Engineering Laboratory.

"We took the bridge to its extreme, almost double what we planned at the outset," Ian Buckle, professor of civil engineering and director of the large-scale structures lab, said. "Preliminarily we see that in low amplitude earthquakes the weight of the vehicles actually helps the seismic effects on the structure, while at higher amplitudes the trucks hinder considerably the bridges ability to withstand an earthquake."

The trucks bounced and swayed as the four-span bridge's concrete columns deflected more than 14 inches in each direction, the steel girders twisted and the floor of the lab shook from the energy applied to the bridge. The bridge, with 80 feet of curvature, filled the cavernous high-bay lab on the University of Nevada, Reno campus from end-to-end.

A 3-minute video featuring the largest motion applied to the bridge can be viewed by clicking on this link http://imedia.unr.edu/media_relations/VNR_shake_trucks_2b.mp4.

"Whether you saw the experiment in person or watch the video, remember that this is a 2/5 scale model, and the movement you see would be two and a half times greater on a full-scale bridge," Buckle, principal investigator of the research project, said. "It would be scary to be driving under those conditions."

"Currently, bridges are not designed for the occurrence of heavy traffic and a large earthquake at the same time," he said. "With increasing truck traffic and frequent congestion on city freeways, the likelihood of an earthquake occurring while a bridge is fully laden is now a possibility that should be considered in design. But there has been no agreement as to whether the presence of trucks helps or hurts the behavior of a bridge during an earthquake, and this experiment is intended to answer this question."

The complete answer will come after months of examining the many gigabytes of information gleaned from the 400 sensors placed on the bridge and trucks. The results of this work, titled "Seismic Effects on Multi-span Bridges with High Degrees of Horizontal Curvature," will be used to frame changes to current codes and lead to safer bridges during strong earthquakes.

The four, 50-ton capacity shake tables simulated more than twice the strength of the 1994 Northridge, Calif. earthquake, which resulted in 33 deaths, 8700 injured and $2 billion damage in southern California. The ground acceleration of that quake was one of the highest ever instrumentally recorded in an urban area in North America, measuring 1.7 g (acceleration) with strong ground motion felt as far away as Las Vegas, Nev., more than 270 miles away. Through computer programs, the recordings of the quake control the hydraulically driven shake tables to simulate the seismic event in the University's lab.

Six different configurations of the curved bridge will be tested in the experiment that will continue for several more months, without the trucks, to examine different components, including column design, abutment design, seismic isolation systems. The bridge was designed by a team of eight graduate students under the supervision of Buckle and two other professors, Ahmad Itani and David Sanders, in the civil and environmental engineering department. The team includes Project Manager Kelly Lyttle, and graduate research assistants Moustafa Al-Ani, Michael Levi, Eric Monzon, Ahmad Saad, Danielle Smith, Chunli Wei, Joe Weiser, and Hartanto Wibowo.

The California Department of Transportation is one of the agencies sponsoring the live load portion of the experiment. The testing of this model is part of a larger project, investigating seismic resilience of highway systems, funded by the Federal Highway Administration.

The University of Nevada, Reno earthquake simulation facility is managed as a national shared-use Network for Earthquake Engineering Simulation equipment site created and funded by the National Science Foundation to provide new earthquake engineering research testing capabilities for large structural systems.


Story Source:

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


Cite This Page:

University of Nevada, Reno. "Engineers simulate large earthquake on curved bridge." ScienceDaily. ScienceDaily, 28 September 2011. <www.sciencedaily.com/releases/2011/09/110923104224.htm>.
University of Nevada, Reno. (2011, September 28). Engineers simulate large earthquake on curved bridge. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2011/09/110923104224.htm
University of Nevada, Reno. "Engineers simulate large earthquake on curved bridge." ScienceDaily. www.sciencedaily.com/releases/2011/09/110923104224.htm (accessed September 22, 2014).

Share This



More Earth & Climate News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Hundreds of Thousands Hit NYC Streets to Protest Climate Change

Hundreds of Thousands Hit NYC Streets to Protest Climate Change

AFP (Sep. 22, 2014) Celebrities, political leaders and the masses rallied in New York and across the globe demanding urgent action on climate change, with organizers saying 600,000 people hit the streets. Duration: 01:19 Video provided by AFP
Powered by NewsLook.com
Inside London's Massive Sewer Tunnel Project

Inside London's Massive Sewer Tunnel Project

AP (Sep. 22, 2014) Billions of dollars are being spent on a massive super sewer to take away London's vast output of waste, which is endangering the River Thames. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Washed-Up 'Alien Hairballs' Are Actually Algae

Washed-Up 'Alien Hairballs' Are Actually Algae

Newsy (Sep. 22, 2014) Green balls of algae washed up on Sydney, Australia's Dee Why Beach. Video provided by Newsy
Powered by NewsLook.com
Was The Biggest Climate March In History Underreported?

Was The Biggest Climate March In History Underreported?

Newsy (Sep. 22, 2014) The People's Climate March in New York City drew more than 300,000 people, possibly a record-breaking number. Was the march underreported? 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:
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