Featured Research

from universities, journals, and other organizations

Virtual Research On Earthquake Resistant Structures

April 12, 2007
University of California - San Diego
The powerful earthquake struck suddenly, shaking the seven-story building so hard it bent, cracked and swayed in response.

Movies created by SDSC visualization experts using data from a sensor-equipped building give UCSD engineers a powerful tool to explore structure performance from different perspectives in full-scale earthquake shake table experiments.
Credit: Amit Chourasia, SDSC Visualization Services

The powerful earthquake struck suddenly, shaking the seven-story building so hard it bent, cracked and swayed in response.

Related Articles

But this was no ordinary earthquake. In a groundbreaking series of tests, engineering researchers from UC San Diego’s Jacobs School of Engineering jarred a full-size 275-ton building erected on a shake table, duplicating ground motions recorded during the January 17, 1994 Northridge earthquake in Los Angeles, California.

To record the impact on the building, the structure was fitted with some 600 sensors and filmed as the shake table simulated the earthquake, yielding a flood of data including stress, strain, and acceleration -- so much information that engineers were having a hard time making sense of it all.

That’s where visualization experts from the San Diego Supercomputer Center (SDSC) at UC San Diego came in.

“By recreating the shake table experiment in movies in a virtual environment based on the observed data, this lets engineers explore all the way from viewing the ‘big picture’ of the entire building from a 360-degree viewpoint to zooming in close to see what happened to a specific support,” said SDSC visualization scientist Amit Chourasia. “Integrating these disparate data elements into a visual model can lead to critical new insights.” 

Added José Restrepo, a professor of structural engineering at UCSD, “These visualizations give us an intuitive way to see how the building behaves in our shake table experiments -- this tool will be very valuable in helping us understand the tests in ways we can’t from traditional approaches, and also in sharing this research with other engineers and the public.”

The costliest quake in U.S. history, the magnitude 6.7 Northridge event prompted calls for more scientific evaluation of structural elements, leading the engineers to conduct the building tests on one of the world’s largest shake tables at UCSD’s outdoor Englekirk Structural Engineering Center.

A paper by Chourasia describing the project was published in a special graphics issue of ACM Crossroads, the student journal of the Association for Computing Machinery.

In addition to helping engineers understand the earthquake’s impact on the building, the visualizations can also give researchers a tool to do “what if” virtual experiments.

“We found that the recorded motion aligns very well with the movie we created,” said Steve Cutchin, director of Visualization Services at SDSC. “This is important because knowing the model is accurate means it can be used to take simulated earthquake data and predict the sensor values -- you can ask, ‘What if a larger 7 point earthquake hits?’ and simulate how the building will shake in response.”

To make the visualizations more useful and provide a rich visual context, the researchers wanted to incorporate recognizable elements from the surroundings, which meant integrating features from the actual video footage recorded during the test. “Our goal was to have fidelity not only in rendering quality but also in visual realism,” said Chourasia. In addition, the integrated video would let the researchers validate this virtual reconstruction visually.

Once Chourasia and his colleagues had developed the building model and animated the deformation caused by the shaking, they worked to align the virtual camera and lighting with the real world video camera so that the scene would match in the recorded footage and the virtual version.

“However, when we tried to composite the actual video footage, we found that the instruments had sampled the data at 50 Hz but the video was recorded at 29.97 Hz.,” Chourasia explained. “And there wasn’t any timing synchronization between the building sensors and camera.” This posed a serious hurdle for compositing.

“After viewing the video footage, we noticed that the recording also contained audio data, because the moving building and shake table make noise, and this proved to be the key.” By “listening to the building” and analyzing the audio and sensor signals, the researchers were able to synchronize the video and instrument data for the visualization.

In the future, the visualization researchers plan to develop lighting models for more realistic rendering and to find automated ways to match the real and virtual cameras. They are also distilling lessons learned from this study into requirements for a visualization workbench for analysis of the dissimilar types of data that come from structural and seismic experiments.

In addition to providing visualization services for the shake table experiments, SDSC is also home to the NEESit Services Center (NEESit) which is developing and maintaining a state-of-the-art grid to meet the cyberinfrastructure needs of the earthquake engineering community, including the UCSD facility and 14 other collaborating experimental sites across the nation.

This research was supported by the National Science Foundation.

Story Source:

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

Cite This Page:

University of California - San Diego. "Virtual Research On Earthquake Resistant Structures." ScienceDaily. ScienceDaily, 12 April 2007. <www.sciencedaily.com/releases/2007/04/070411135030.htm>.
University of California - San Diego. (2007, April 12). Virtual Research On Earthquake Resistant Structures. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2007/04/070411135030.htm
University of California - San Diego. "Virtual Research On Earthquake Resistant Structures." ScienceDaily. www.sciencedaily.com/releases/2007/04/070411135030.htm (accessed December 19, 2014).

Share This

More From ScienceDaily

More Matter & Energy News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
3D Printed Cookies Just in Time for Christmas

3D Printed Cookies Just in Time for Christmas

Reuters - Innovations Video Online (Dec. 18, 2014) — A tech company in Spain have combined technology with cuisine to develop the 'Foodini', a 3D printer designed to print the perfect cookie for Santa. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
First Etihad Superjumbo Flight in December

First Etihad Superjumbo Flight in December

AFP (Dec. 18, 2014) — The first flight of Etihad Airways' long-awaited Airbus A380 superjumbo will take place later in December, the Abu Dhabi carrier said Thursday, also announcing its first Boeing 787 Dreamliner route. Duration: 01:09 Video provided by AFP
Powered by NewsLook.com
Ford Expands Air Bag Recall Nationwide

Ford Expands Air Bag Recall Nationwide

Newsy (Dec. 18, 2014) — The automaker added 447,000 vehicles to its recall list, bringing the total to more than 502,000. 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.


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


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