[music playing]
NARRATOR: Is Los Angeles prepared for a 7.5
magnitude quake?
Could emergency agencies and workers
cope with the damage, injuries, and deaths
that would inevitably occur?
And which buildings and structures would be
able to withstand the shaking?
To understand what would happen to structures,
engineers at the University of California at San Diego's
Englekirk Center have created the world's
most powerful shake tables.
These are special platforms that subject
building materials and even buildings to simulated quakes.
This is the shake table that moves back and forth
to simulate the ground motion.
You wouldn't want to be here during an actual test
because it would be like being at the epicenter
of an earthquake, a pretty frightening experience,
for sure.
[music playing]
NARRATOR: This seven-story building
was constructed on the world's only outdoor shake table.
Engineers use structures like this to see how buildings would
hold up during an actual quake.
In another section of the university,
at the Powell Structural Research Laboratories,
other shake table tests are being conducted.
FRIEDER SEIBLE: What we are testing here
are components which are being used to protect our structure
against earthquakes.
We call it our seismic response modification devices,
like big rubber bearings, big sliding bearings, big dampers
like oversized car shock absorbers,
which we build into our big structures
like bridges, or dams, or buildings
to protect these structures against the seismic load input.
[buzzer]
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NARRATOR: Tests like the ones conducted at UC San Diego aid
structural engineers and ultimately help shape
California's building code.
[swoosh]
In Los Angeles, Nick Delli Quadri, engineering bureau
chief at the Department of Building and Safety,
helps to enforce the code.
- 211. - Right.
[swoosh]
NARRATOR: He also has his concerns
about the possible effects from a Puente Hills earthquake
on LA's older buildings.
NICK DELLI QUADRI: We've developed standards
with the engineering community for strengthening
nonductile concrete buildings.
We work with those engineers.
We use those standards whenever we have the opportunity
for a building that's going to be changed to a different type
of use or remodel.
[swoosh]
NARRATOR: Downtown LA is experiencing an economic boom,
and many older commercial buildings
are being remodeled, restored, and converted
to residential use.
NICK DELLI QUADRI: This is an historic hotel that's being
converted to residential lofts.
As you can see, it looks like-- it's a brick facade on it,
but it's actually a concrete building.
They're adding strengthening to this building
by putting in concrete shear panels between the columns
and the floors.
There's an example of it here with reinforcing steel.
[music playing]
NARRATOR: The Retrofit Project is aimed at preventing
a collapse during a quake.
Not every building can be retrofitted.
After the Northridge Earthquake, Parker Center,
the LAPD's downtown headquarters,
was found to be beyond retrofitting.
It's scheduled for demolition.
Meanwhile, a new emergency operation
center is being built to the latest
seismic safety standards.
NICK DELLI QUADRI: It uses a based isolation system, which
reduces the earthquake forces that go into the building,
and reduces some of the design requirements on the building
itself.
NARRATOR: Base isolators act as shock absorbers
so that during an earthquake the movement of the ground
is dissipated into the base isolators, not the building
above them.
NICK DELLI QUADRI: The emergency operations center is
supported on 64 base isolators.
There are 64 of these pendulum based isolators that are used
to-- to support the building.
NARRATOR: As for LA's steel frame high rises,
there is currently debate in the scientific community
as to how they would perform in a 7.5 quake.
During the Northridge Earthquake,
more than 120 such buildings had joint failures,
but does that mean they would collapse?
The key issue is whether the building will fall,
or whether it will endanger the occupants.
And our feeling--
I'm talking about an industry feeling
based on even the performance of the steel frame buildings
during the Northridge Earthquake--
is that we will not experience collapses.
NARRATOR: But not everyone is so sure.
During a 7.5 earthquake, the ground surface in downtown LA
could actually move anywhere from 5 to 10 feet
relative to the Earth below.
[swoosh]
And though tall buildings are designed
to sway like the proverbial palm tree,
beyond certain parameters, there could be a breaking point.
[swoosh]
TOM HEATON: The majority of steel frame buildings,
we'd see some fracture of the welds--
welded connections.
What would happen next?
We're not quite sure.
Some of the simulations say that it's feasible
that some of the steel frame buildings
could actually collapse.
NARRATOR: For the time being, the debate
will continue, and won't be resolved until the earthquake
actually occurs.
It will cause a lot of destruction.
And so we have to deal with a major disaster,
and we have to be prepared for that.