IF THE PROSPECT of a mega-earthquake
has you quaking yourself—fear not, because
UC San Diego engineers are making sure our
world will withstand the rumble. Researchers
at the Jacobs School of Engineering are
preparing to mitigate the effects of a large-scale earthquake by testing a six-story, lightweight steel-frame building to determine
how it will fare during a tremor and fires
that may follow.
The structure, the tallest cold-formed
steel-frame structure to undergo tests on
a shake table, was built to represent a multi-family residential condominium or apartment. It was placed through a series of
simulated temblors of increasing intensity
that mimicked actual earthquakes.
As a better way to determine stress on
the materials, the building’s performance
was captured by an extensive array of more
than 250 analog sensors, as well as digital
cameras and aerial drones. Structural
engineering professor Falko Kuester, who
leads UC San Diego’s DroneLab, used
unmanned aerial vehicles (UAVs) to capture
both the seismic and fire testing and create
a high-resolution 3-D model and video of
observed damage. Engineers can use virtual
reality (VR) to zoom in to see the tiniest
details, such as cracks and changes in shape
“This is big VR for big data and big
science,” says Kuester.
As for the building? “It could have been
easily repaired,” said structural engineering
professor Tara Hutchinson. “The occupants
would have gotten out safely.” Hutchinson
believes the structure fared well because it
is lighter than a concrete building and has
less mass to generate damaging forces.
Fire was less kind to the structure,
however. Plastic fixtures and hardware
melted, as did several video cameras
installed to capture the fire’s progression.
Simulated quakes occurring after the fire
tests further weakened the structure’s
floors, bringing it close to collapse.
All the better to learn these effects in a
test environment, however. The combination
of these technologies— a one-of-a-kind
outdoor shake table and powerful data
visualization methods—allows structural
engineers at the Jacobs School to produce
an incredibly detailed digital model of the
structures they test. This in turn allows
them to make recommendations to improve
design methods and building codes around
the nation and around the world for when
the Big One, or maybe the Mega One, hits.
12 years strong
The table has been shaking things up
since 2004 and supports up to 2,000
tons—about 400 elephants (or 11 of the
Stuart Collection's Bear sculptures.)
It can replicate the ground
motion of the world’s largest
earthquakes, including California’s
6.7-magnitude Northridge earthquake (1994), the 7.2-magnitude
Cape Mendocino earthquake
(1972) and the 8.8-magnitude
Maule, Chile earthquake (2010).
The table is located just off the
I- 15 highway and Pomerado Road
(though you’d never notice without
a bright green building on top.)
Structural failures are recorded
for analysis—watch the walls
come tumbling down at
Did you know UC
San Diego is home to
the world’s largest
outdoor shake table?
Here’s some more
facts to be aware of:
Data from sensors, digital cameras and
aerial drones allowed for an incredibly
detailed digital model of the building.