Visualization experts from the San Diego Supercomputer Center are collaborating with structural engineers from UCSD’s Jacobs School of Engineering to make groundbreaking advances in the field of virtual research on earthquake-resistant structures.
Powell Lab employees such as Giri Rajaparthy work in conjunction with the UCSD Englekirk Center to examine how earthquakes and other phenomena affect buildings.
In their most recent experiment, engineering researchers Jose Restrepo and Marios Pangitou jarred a full-size 275-ton building erected at UCSD’s Englekirk Center, which works in collaboration with the Charles Lee Powell Structural Engineering Laboratory in Earl Warren College.
The center, which houses the largest hydraulics-powered shake table in North America, allowed the researchers to duplicate the seismic activity recorded during the 1994 magnitude 6.7 Northridge earthquake near Los Angeles.
The seven-story structure, fitted with over 600 sensors, was filmed as the shake table simulated the quake, yielding a flood of data including calculations of stress, strain, displacement and acceleration.
The sheer amount of information provided by the test made it difficult for the engineers to make sense of the overwhelming flood of data; that’s where SDSC visualization researchers began their work.
“”Our role at the SDSC is to help scientists by using graphic tools to convert their data and calculations into a visual representation that demonstrates the effects of seismic activity on the building,”” SDSC visualization scientist Amit Chourasia said. “”It is difficult to look at a series of data and figure out what’s really going on with a building. Showing a person the values for the amount of stress on a particular part of the building or the displacement really doesn’t mean much to the average person, but a visual representation of the building does.””
The visualization experts worked with the data from the shake table experiment to create 3-D images and animated movies of the building as it endured seismic activity. The images and videos now serve as a powerful tool for engineers to explore the structural performance of buildings from multiple perspectives that they could never access before.
“”Before conducting experiments with the shake table and visual analysis, engineers didn’t have a way of knowing how their buildings would react to an earthquake until one actually happened,”” Visualization Service Manager Steve Cutchin said. “”Simulations based simply on logical analysis can be wrong, and that is why it is so important for scientists to get the physical data from the shake table and visualization experiments as well.””
Cutchin added that although a small discrepancy in the actual displacement, as compared to the predicted displacement, or stress on the building may hardly seem like a significant problem, it can mean the difference between a structure standing or collapsing during an earthquake.
Fortunately, with the innovative visualization technology of SDSC, engineers are much less likely to have such problems predicting how a building will respond in the event of a disastrous quake.
“”By focusing one or two or even multiple cameras on a building, as was the case before, we only had a limited view of what was going on,”” Chourasia said. “”With our technology, however, we can view the big picture from all 360 degrees, or we can zoom in on specific parts of the building during the earthquake to figure out the particular strain on a certain area of the structure, giving us critical new insight about the behavior of the building.””
According to Cutchin, the visualizations produced by SDSC can also give researchers tools to do virtual hypothetical experiments in addition to helping engineers understand the earthquake’s impact on the building. The building’s motions align well with the movies created from the sensor data, allowing researchers to make close predictions of the building’s hypothetical sensor values.
Engineers can then ask, “”What if a larger earthquake hits?”” and simulate how the building will shake in response to the quake.
In addition to the revolutionary victory in earthquake research that SDSC and the Jacobs School of Engineering achieved, Chourasia also said that this development means a great triumph for the field of engineering as a whole.
“”As this project demonstrates, engineering is becoming an increasingly collaborative field,”” Chourasia said. “”Instead of being the isolated discipline that it once was before, engineering is combining with several other disciplines such as visualization and computer science, as well as many other fields in order to pioneer new methods to keep structures safe in the face of earthquakes.””