[music]
Miles O’Brien: We’re a couple of hours away
from low tide.
[scraping]
Miles O’Brien: It’s time to get in the water.
[scraping]
Miles O’Brien: It’s deployment day
for this team from the University of Florida.
They’re attaching six water pressure sensors
to a bridge along Florida’s Atlantic coast,
an area often in the cross hairs of a hurricane.
Jennifer Bridge: These are oftentimes
the only way that people can evacuate those regions
and that emergency services can get into those regions,
so they’re really important from that perspective.
Miles O’Brien: With support from
the National Science Foundation, civil engineer Jennifer Bridge
and her colleagues want to understand
how to make bridges safer and provide an early warning
if a bridge has been damaged by a storm.
To do it, they’ve developed this bridge-
mounted sensor system to collect data at the source
and transmit it back to their lab in real time,
during a hurricane.
Jennifer Bridge: There have been lab studies
to look at wave and surge loads on bridges,
but to date, there hasn’t really been anything on bridges,
especially during storm events.
Miles O’Brien: They’re particularly interested
in looking at concrete bridges vulnerable
to hurricanes in low-lying coastal areas.
Jennifer Bridge: These are the type of bridges
where we saw failure during Katrina and Ivan
and previous hurricanes where you would see the deck
kind of came off the supports of the bridge.
Student: 21 right now…
Miles O’Brien: The day before the deployment,
the team did some final tests on the sensors back at the lab.
Grad student Carlos Soler Ayoroa showed us the inner workings.
Carlos Soler Ayoroa: So, this is the actual pressure
sensor that’s inside the PVC enclosure
that’s going to be attached on to the bridge.
Miles O’Brien: The next morning,
they loaded up their truck
and hit the road early, headed for the coast.
Jennifer Bridge: We’ve put a lot of effort
into identifying structures throughout the state
that are vulnerable,
that are appropriate, that are accessible,
so that we can go in directly ahead of a storm
and try to get the data we need.
Miles O’Brien: Eventually, they plan
to rapidly deploy in front of approaching storms,
to wire-up bridges immediately in harm’s way.
Jennifer Bridge: Right now,
we’re still operating in the mode of,
‘Let’s just put it up for the hurricane season
in as many locations as we can and cross our fingers.’
Miles O’Brien: Data from water pressure sensors
can tell them a lot about what’s going on at the bridge
during a hurricane,
like water levels and storm surge measurements.
They’re also gauging “impact loads” -
forces generated by water pounding the bridge
from the side every time a wave hits.
Jennifer Bridge: And in order to capture
the impact forces on the bridge piers,
we’re measuring pressure, the water pressure,
both on the front of the pier and the back of the pier,
and by looking at the difference between those two pressures,
we can get that horizontal force.
Miles O’Brien: Cables connect the sensors
to a solar-powered hub located up on the bridge deck.
Here the data is recorded
and also streamed back to the University wirelessly.
They’re tackling a difficult hardware and software challenge
to put together a system robust enough
to keep operating under hurricane conditions.
Jennifer Bridge: We do have storage
in our system on site, so should we lose communication,
we can go back in later and try to extract that data.
Now, that’s assuming that the brains of our sensor system
haven’t also been washed away.
The way that we try to prevent that happening
is that system is up on higher ground.
So, we try to put that in a less vulnerable location.
Miles O’Brien: At the end of the day,
they still had some work to do tying down all those cables.
They went back a few days later and finished the job.
Jennifer Bridge: What we’re measuring right now
is the wave and the water loads on the structure.
What we’re not measuring right now
is how the structure is responding to those loads,
so the types of sensors we may add in the future
will be sensors
that can actually capture the response of the structure.
Miles O’Brien: Engineering more resilient
infrastructure,
understanding better what’s happening with coastal bridges
when they ride out a storm.
For Science Nation, I’m Miles O’Brien.