Hello and welcome to the physics world weekly
podcast. I'm Hamish Johnston.
Earlier this year, the world watched in horror.
As the Francis
Scott key bridge
collapsed after being struck by a large container
ship.
6 people were killed in the disaster, which
occurred near Baltimore Maryland
in the Us.
In this episode, Physics World's Margaret Harris is
in conversation with Aaron Bell. A university of
New Hampshire engineer who specializes
in the structural design and dynamics
of bridges.
She explains why the Bridge C apps and
talks about what can be done to avoid
future catastrophes.
Joining the conversation later on apps is Bell
new Hampshire engineering colleague,
Martin W,
who specializes in fluid flow.
Together, they talk about the living bridge project,
which looks at how bridges can become more
integrated
international
infrastructure.
By doing things like generating
renewable
energy using water turbines.
Here's that
conversation.
1 of the first things we learn about
is physics students is static forces,
so forces that act an objects at rest.
These forces are straightforward compared to the ones
we meet in general longevity and quantum mechanics,
which is why we learn about them first,
but this apparently is simple behavior, can give
rise some surprisingly complex and even terrifying events,
especially when those forces suddenly cease to be
static.
As tragically happened in March when a container
ship struck a bridge near Baltimore in the
Us. Here's tell us more about bridges in
the science of how they stay up or
ball down is Aaron Bell, a professor of
Civil and an environmental engineering at the university
of New Hampshire and an expert in bridge
health.
Hello, Aaron. Welcome to the podcast.
Hi. Good morning. Thanks for having me. What
actually happened on that night of March 26.
On March 20 sixth, the around
12:45 or just past midnight,
the dolly, which is the, vessel
left its port. It was
led by tug out of its birth and
then released and about 01:20
in the morning,
it lost power,
and luckily, the captain about 01:27
put out a may day call that he
had lost power and notifying that the a
collision was well that allowed the Maryland state
police to actually shut the bridge to traffic.
It was, you know, obviously very early in
the warnings.
The lost power power was able to come
back on, and then they lost power again,
and then just about 90 sec seconds after
the May day call, it was the impact
to the bridge, and it's actually struck the
southwest
pure of the central large trust span.
And it was traveling at relatively high speed.
It was at 8 knots
which,
9.2 miles per hour may not seem like
a lot but 8 knots is if any
listeners are nautical a. It's pretty fast, the
data, it was troubling about 8 knots or
a little bit above 8 knots when it
impacted the collision, and it broke the bridge
itself. Into several parts
because of the energy impact into the pier,
which if energy comes into it a object
there's really 3 things that can happen, either
the object can absorb the energy, the object
has damage due to the energy or the
object has movement.
And I think what we saw was movement,
which then caused damage, which had led to
our cascading gaining failure.
Now, what did this bridge look like before
it collapsed? How is it designed? Tell us
a little bit about the bridge itself? So
this was a through truss bridge?
Which
meant that the trust structure itself spanned over
multiple peers or supports,
and then those spans
weren't
independent, they were interdependent. And I think that
now when you watch the video of that
cascading failure, that inter dependency
makes a little bit more sense.
So if you look at the bridge, it
may look very... It looks like a trust...
It's a trust bridge, and it can also
look like a can bridge, which is maybe
if you think of the fear the fourth.
Or some of the other bridges here in
the United States where the spans itself almost
satellite out from the pier.
But then when they meet in the middle
that meeting in the middle is almost like
a fuse, so you wouldn't have a cascading
failure across where this through trust sits on
the piers, and then they rely on their
adjacent spans for distributed load. So a through
trust can be smaller members,
so it can use less material,
but then we have a little bit less
redundancy in the system.
And 1 of the things as bridged designers
when you're looking at,
protecting your bridge. It's not always making the
members bigger. It's adding redundancy,
to anything that could happen to them. So
a bridge, like, the Francis Scott Key, which
is in a very busy,
water way was designed in 19 77,
and it had... It did have pure protection,
but it was obviously woe fully under size.
So if you look at some of the
videos, you see very, they look they look
very small next to the container shipped
protection tool called the dolphin, which is a
sac official concrete
pure basically pure that supports nothing, but is
structurally independent, and meant to be sac
so that a container ship would hit it,
absorb some of the energy or potentially actually
change of course.
If you see the modern
dolphins since then they are much, much larger.
And part of the reason for that is
in the United States in 19 80,
the Sun sunshine Sky bridge in Florida
had a vessel collision, and there was a
loss of, I think, 35
lives,
and post post that collision, the, federal highway
administration which manages all of our bridges,
funded study to look in the design codes
for a specifically vessel collision. And in 19
91
Asha, which is the American Society of State
and Highway transportation officials publishes, the first guide
specification for vessel collision,
That's a collision design for highway bridges.
And that code obviously comes out 14 years
after this bridge has been constructed.
I think that over the year over the
coming months and years we'll really look at
what was the decision making in Maryland?
That led
no retrofit to this protection,
especially as if you think about the the
container ship that was used in 19 77,
versus the container ship that's used in 2024,
it's about 10 times larger and weighs about
10 times more
So whatever was,
a, a adequate peer protection system or vessel
collision protection system in 19.
77
clearly is not now. So 1 of the
things that I think will be evaluated. And
I think this is this will be beyond
bridge design, but it really will be systems
design. So there's only so much we can
do with physics.
Because we just can't build something
big enough in a real way to absorb
the energy. This is that kind of first
locks thermodynamics, energy can neither be created or
to destroyed I think that's thermo. So if
you think of all of the energy coming
into that coming with that ship, thermo that
energy just caused that huge deflect deflation of
the trust structure
off of the peer cap, and then that
that large deflect deflation or large defamation was
just too much for the system to absorb
and and led to a cascading failure.
So I think that in the Us, we
will see changes not only to evaluating
if a vessel,
collision protection system is adequate,
but related to the bridge. So if it's
a redundant peer
appear that has enough inertial force to absorb,
the energy impact, it will also be the
sac superficial elements, whether it's a fend system
or the islands around that have those separate
structurally independent kind of tips that then can
be damaged that meant to be damaged
or the dolphins, but also how we support
navigation in the waterways.
When do we use tug boats
I think 1 of the big questions being
asked is that that vessel being so large,
and it did have Tug assist. And getting
out of dock? Why didn't have tug assistance
all the way through the port. And I
I think they'll be... It won't just be
1 solution. It will really be multiple
checks
and the end, you know, checks throughout the
whole process of of, these ships have to
move through these ports,
that's how the economy functions, and then how
can we support them because as structural engineers,
you know, it's not meant to be gl,
but it's true that if you build it,
they will hit it, and that's everything,
whether it
and, unfortunately, after 09:11 in 2001, it became
plain impact. But if you looked at any
type of bridge structure,
you really thought about it, and we still
do. You think about... If you if you
think of a cable state bridge, we really
think about what if you lost 3 cables
due to a...
Tractor trailer collision with them, can the bridge
stay standing. We think about those things of
having redundancy in the system being able to
have
redistribution of forces
and also, how how we use the... How
we use these systems. And so I think
this will be an additional, very large, very
impact full data point of how we look
at the overall design of not just the
bridge itself, the surrounding areas and then how
we support the use of it that it
it has redundancy,
and I think, 1 of the things going
back to the tug vote is, you know,
a ship of that size would have multiple
tug,
but guiding it through the water way, and
so you wouldn't have a loss of engine
power that would be a single point of
failure. You actually have multiple
tug that would be available. So I know
here in new England, our our ports are
much... Smaller, and our waterways are much narrower.
So all ships that come in. It's not
a Us coast guard
requirement, but all ships that come into any
ports in New Hampshire or Maine or even
Massachusetts. They come under not their own power,
but by Tug boats to guide them, and
those tug bolt pilots are very familiar with
the currents,
with the the symmetry of the, water way
with the peers with the obstruction
because I think we have to remember. A
bridge is an obstruction
to a nav water way. We have to
get a permit to be there at least
in the Us, you have to get a
permit because you are in obstruction as a
bridge the sea faring traffic really takes precedence.
And so working with that as a system,
not necessarily just the stand building a behemoth
of a bridge that that could take anything,
but really looking at the system and that
distribution of risk. It's across multiple multiple parts
that play a role in, the safety of
the traveling public both from a naval
standpoint and also the he standpoint. It's interesting
that you focus on the fact that the
bridge is the obstruction here because I think
in the immediate aftermath, we saw a lot
of analyses about, oh, what's this gonna mean
for highway traffic, You know, people are using
this bridge to commute between different parts of
Baltimore around that's... It's part of the the
city's belt way, I think. But actually the
more importance
obstacle caused by the bridge disappearing is actually
the fact the bridge is in the water
or was in the water and it's blocking
the channel. There's this this navigation channel.
Yeah. The the bridge itself has a very
local impact in terms of its inability to
be used for a passage for vic... Killer
traffic. So you see a very local impact
from that, but the fact that it's blocking
a water away of 1 of the big
busiest ports in the Us has a global
impact.
So there's a broader view from this that
has to be looked at, and I think
that's, you know, when, people ask me how
long it will take to
rebuild this bridge. And there really is going
to be a almost like a gated
review of how this is going to go
because the first the first top priority is
getting the port open.
So getting the the debris out of the
water. And then the next thing I think
will be evaluating the peers.
1 of the things that that I think
will be evaluated is can those peers now
with new technology
to have longer spans be moved further outside
of the shipping lane. So I... It's it's
all of those pieces that reduce the risk
of impact. Do we move it, you know,
outside of the shipping lane coming being again
here from New England. We have a bridge,
the Maurice j To bridge, which is Big
bridge in downtown Us and people were very
concerned about that. But those peers are so
outside the shipping lane that I'm pretty sure
a vessel would go ground before it would
hit peer.
And that's, I think what you also wanna
look at is do you have
protection just from the of your port?
That will help you on your... So using
everything that's available to you. But if you
are a resident of Baltimore,
that traffic is the first thing you think
about And there's also a confidence
that happens or a lack of confidence of
traveling these roadway or these bridges that are
a necessity,
Our bridges are our links
across either waterways or other highways that link
communities together. So just like after the Sunshine
high way There was a lot that the
bridge community had to do to build confidence.
I think that will happen here
as well. I mean I think we know
more about bridge behavior way but I think
this is 1 of those things there's still
a lot for us to learn,
and we will learn about,
the redundancy and robustness of... For, this specific
type of bridge design kind of moving forward,
and it still is a valid bridge design,
but maybe we look at anchorage in a
different way or maybe we look at protection
of, that energy impact as a different way.
Maybe there's some absorption,
energy... You know, some absorption tools that we
use or along there, but I do think
that the the traffic is an impact.
The vessel traffic is the bigger impact. So
you... Obviously, you want to rebuild the bridge
as quickly as possible, but as quickly as
possible has to take into the fact that,
you know, maybe you don't wanna build as
well... Actually, you will certainly don't wanna build
a bridge that's exactly the same as what
came before because that bridge had
as we've now seen tragically with the loss
life and the the damage to the bridge.
It had 2 little redundancy and structure. Its
peers were not not necessarily as well protected
by these these dolphins you talk about and
it was maybe not as well coordinated with
the
so the the the water shape of as
as it could have been. I think a
big decision will be... And I think... Will
really impact the cost is if they reuse
those peers
with additional protection because the biggest cost to
building a bridge getting out of the water.
Will that's the number. I mean, it's really
hard to build in the water. So if
you can reuse peers or you can limit
the construction,
1, that you limit the environmental impact, the
less you disturb the water, especially the bottom
that really limits your cost.
And a a great example is we have
2 vertical lift bridges here in the port
of Ports smith in the Pis River way
and 1 bridge was replaced in 2013,
and the cost was about 80000000,
but they rehab and reused the peers.
So the construction underwater was really minimal
because that the peers were reinforced and then
the second 1, the opening was so small.
That a Panama max ship couldn't go through
it. So they changed the opening and that
bridge cost about a 660000000.
So your cost and your timeline really changes
depending on your usage, but as you kind
of pointed out,
there will be a lot of I eyes
and a lot of thought into is reusing
these peers the right thing or is there
a totally different form of bridge that that
we could produce. And I think, again, if
you look at Florida, they totally went from
a trust bridge to a cable state bridge
when when it was finally,
rebuilt and and could that really kind of
changed our look. This the state of Delaware
is in the middle of a vessel collision
protection project
for the Delaware Memorial bridge. So there'll be
a lot of
consideration about how did Delaware make the decision
that it needed to up its game in
terms of vessel collision for a November... I
think the project started in October or November,
but Maryland did not. And I think,
you know, Sunday, Monday morning quarterback,
is something we do a lot because there's
so there's only so many resources, and there's
so many assets that need to be managed.
And we saw this after hurricane Katrina when
it was well why weren't those levi, the
ones that was fixed. Why wasn't... You know,
so we really do our best to predict
where we're going to need the at... Where
with the resources,
and and then, unfortunately, sometimes,
those predictions just are not as accurate as
we would like them to be.
Yeah. Yeah. We're talking about the collapse of
this bridging in Baltimore,
in part because it's unusual It's unusual that
a brings collapse at all. Yeah. And it's
unusual that it clasp because a a great
huge ship ran into it rather than some
more mundane,
cause?
What are some of the more common causes
of bridges
failing.
So a lot of people ask about that...
Says this bridge was actually inspected,
the last inspection had it as a fair.
So we don't know. Fair sounds okay. It's
not great, but I don't think the structural
condition of this bridge had anything to do
with its. Collapse. I mean, I think any
any bridge with that much energy coming into
it,
where there was really no dis disposition
mechanism
besides the damage.
If you think back to the 2007
collapse in Minneapolis
Minnesota, the I 35 bridge collapse, it was
a buckled gus plate that then had a
cascading failure. And since then, we've really looked
at, this idea of the fracture critical bridge
or the... The... Those bridges that have the
element that if that element fails, there's no
redundancy in the system and you'll have progressed
of collapse. Single point of failure sort of
things. Yeah. Yeah. You have a point of
failure where there's just no catch. There's nothing
that catches have
the the load that red distributes the load.
So we really do look at more robust
systems, but the I 35 bridge collapse in
2007,
and and that really was a failed gus
plate and gus plates are the connectors.
Again, for the physicists, not the engineers, gus
plates are what allows steel members to change
direction because we have straight members are coming
in. If we want them to take a
right hand turn. You you sandwich them in
between a gus plate and then bolt everything
together. So that allows our straight members to
change direction, whether it's a right hand turn
or diagonal for a truss. So those elements
prior to 2007,
in our bridge inspection protocols, those were considered
unexpected quantities.
They weren't considered in our bridge inspection protocols.
And obviously, since 2007,
we've had a lot of publications about how
do you evaluate gus plates.
And even looking at bridges and can we
with new technology,
can we,
remove gus plates?
And actually, the the Memorial bridge that I
mentioned that we reuse the peers in Ports
smith has a gus list trust connection, which
is part of that bridge was actually designed
in 2012,
just 5 years after that collapse.
So I think we, you know, if we
go back to the 19 forties with the
Tacoma narrow bridge collapse, there was just a
lack of understanding of bridge air aerodynamics because
we were just pushing the limits of long
span bridges
that are lighter and narrower.
And, really, you know, if you think about
it more elegant,
and when you translate that
methodology that was being used in New York,
where had big traffic
huge lanes, heavy bridges and you move it
to Washington State that only needs 2 lanes,
so it's much much lighter. There was just
a lack of understanding, that that change was
going to change the dynamic
signature because as you kind of started out
talking about everything equals 0 in the structural
engineering world, everything supposed to equal 0,
you know, some of the forces should equal
0. And when the some of the forces
don't equal 0,
or we have dynamic effects, that's something that's
out of the ordinary for us as
as structural engineers, and we have to think
about really specifically, how can we make sure
that that's
something that we account for, and and we
do that much better now, part of it
is because of the collapse at the Tacoma
narrows, or you could look at in 19
67, the silver city bridge collapse in... Oh,
I think it was Ohio.
When we didn't do routine bridge inspection prior
to that. And that bridge collapse and it
was a fracture of a pin and hanger
that the the crack had probably...
Been there for years,
the bridge collapse, there was a loss of
life, and the response then was we we
should be looking at our bridges, and we
should be looking at them frequently.
So it's usually...
It's it's rare that we have a design
that causes a collapse. We saw that in
Florida with the Pedestrian bridge.
At Florida international,
designed by, fig engineers, which are a very
well known bridge engineering firm,
but the the,
Pedestrian bridge over a highway was meant to
be a
cable state bridge
due to a construction sequencing issue, the deck
went in and and collapsed, and and there
was a loss of life, So each 1
of these,
it's rare that it's a design flaw now
that we know things, but it's a it's
not necessarily the design flaw. It's a use.
An understanding of how it was going to
be used or what it was going to
experience, and I usually tell the students that
we... As designers, were always thinking of the
demand what we're asking,
the structure to do and its capacity. The
capacity is pretty easy.
The demand is what's really hard.
Because you think about... I may design it
for XYZ, well, what happens when Abc happens?
What happens when an extreme event happens? And
how does it behave because... We may design
for when to come from the north, but
what if it comes from the northeast.
And when doesn't do what we would like
it to do? When does what it wants
to do? Just like an earthquake or just
like AAA
hurricane or a a heavy rain or a
snowfall,
So we do our best with historic information
about the risk and the, the
category
or the...
Magnitude of the event that we think is
going to happen in that geographic region where
we're putting this... Whether it's the structure or
the bridge
or or whatever system is there. And,
usually, we do a pretty good job. And
then when we don't, that's when we learn,
and we realize okay, What can we do
about that? And I think we saw that
even with the earthquake in Taiwan with Taipei
01:01 and and the ball doing exactly what
it was supposed to do.
And those... So really,
1 of the things I think that's exciting
about engineering is that we use... The principles
of the natural world, the physics principles, the
mathematical equations that describe those principles to do
our best to predict the future.
And the predict future part that's the hardest
part is what kind of demand are are
they gonna experience over their life?
And that's a vessel collision of this size
or,
natural disaster is really thinking about what's the
worst thing that could happen to this structure.
And can it withstand it. And we almost
look at it in tears.
And really that first tier
is that you wanted to stay open that
people can get you know, people can get
off it safely, that you have enough warning,
the... Or that you know, hopefully, that it
stays open and minimal damage. If you have
a critical...
If the... If your critical is very high.
For example, if it's a 1 path, out
of an area. If your 1
path for first responders, you know, you're really
going to put a lot of effort to
make sure not only can that bridge
survive a storm, but stay open during a
storm.
And then, you know, can it survive the
store, maybe it can't be open during it,
but it can survive it or survive with
minor repairs, and then the worst case scenario
there the can't that you have either collapse
or a replacement. At But,
given resources available, it's usually that tiered of
what what kind of risk can we accept.
And you know, obviously, we do our best
to make sure that the loss of of
life is that is protected as best as
as we can. With with are the knowledge
that we have.
So you talked about various different, sort of
bridge collapse mechanisms you like that have happened
historically in the lessons we've learned from there.
Whether... Whether it's the the fire, the Gus
plate in Minneapolis or in this case, with
the Baltimore bridge, the key bridge,
and you know, a poor inadequate defense and
possibly design contributions.
What do you think is the
next lesson we will hopefully learn without having
a tech catastrophe. What's the thing with is
sort of missing that you haven't patched up
yet?
I think a lot of what we're learning
it about is the
impact of repeated
fatigue use, and we're we're learning more about
that, taking better care of the bridges, realizing
that, not only if we take better care
of the structural actual side. But if we
take better care of how they're used.
So really monitoring
not... And I know people get a little
squirrel about structural if we're monitoring kind of
your your vehicle weight, they're in, you know,
in the United States, especially in New Hampshire,
our armada is live free or die. So
nobody likes, to be monitored,
but from a bridges use standpoint,
most of our vehicles are communicating all the
time to communicating how much they weigh they're
communicating if they're anti like breaks are in.
So I think with that data, we use
it for traffic management.
To be able to bring that into asset
management, so we have a better sense of
the history of use.
So we can get in front of some
of these fracture failures. I think we're already
seeing that
because people are very lea if we were
using that to give citations for overloaded vehicles.
But if we're using it just for the
public safety of, this bridge is actually getting
overloaded multiple times.
I think that's almost like a better use.
Of the data,
I think and and I think that we...
You know, when you see that the the
bridge collapse, I think it was in Indonesia
and it was a 10 year old suspension
bridge. Am Might be having the wrong country.
But it was because it was constantly being
overloaded
because their their major
export was timber.
So lack of management of the the use.
So I think that because
we have cars that are communicating everything else
everything out about them at all times.
And we're using that data in a lot
of different ways, and we like that data
because that tells us it's 6 minutes to
the airport. Or 12 minutes and we're using
that mostly by communication either from the car
or cell phones in the car, but you
have a sense of the use So I
think we're going to... And I'm hoping
that using that data
will help us with actually how the bridges
are being used.
And we can use that as better input
for that demand.
Sorry, and and again, I'm not an Ai
person. I know it exists I don't know
how to use it. But I feel like
there's a lot of that's using machine learning
and machine vision as we're bringing in that
demand data that is just coming in in
drove.
I... When I talk with, my colleagues in
computer science, I think I have big data
and they're like, you you do not have
big data.
Like, Google's buying data is big data. Your
data about the the temperature and the stream
effects on a bridge is is not big
data, but I can still use those tools.
So I can predict the effect of the
bridge during,
different weather weather conditions. I think that's where
we'll have a lot of learning because we'll
have such a better...
Handle on the demand that the bridge is
experiencing.
I'm gonna bring your mechanical engineering colleague Martin
Was now because the 2 of you C
lead a project called the living bridge that
focuses on understanding the stresses and strains. Bridges
face under everyday conditions, and therefore, hopefully, once
you understand those conditions you can prevent those
bridges from failing. Martin, what's that project involve?
But So the living bridge project
is is called that because we instrument
a bridge to
have it talk to us on on how
it senses loads,
also feed its feeds itself was locally available
renewable energy, which case in this case is
title energy, and hence the living rich product.
So it is sensing how it is doing.
It is talking to us, and that it
feeds itself with with renewable in energy. What
do you mean feeds itself? I mean, how
how does that work?
This is some... The bread we chose is
the
memorial bridge in downtown ports,
which is the bridge over title est. Bridges
over title est are typically built at narrow
locations
with the currents are very fast.
And hence, these are good locations to actually
convert some of the available kinetic energy in
the tides as they move in and out,
they flown in both directions.
With tidal turbines to, provide electric energy for
bridge operation and sense sensors bridge operation and
actually turn bridges into internet power producers, net
power plants in general. What the bridge does
with the energy is to basically power its
sensors. And and make sure that that... That's
going on rather than using solar electricity or
or wiring it up? Yes. It that it's
used for sensors and more,
many cases. Solar panels might be an easier.
Choice just to power sensors, of course, but
there's quite a bit of title energy available
in in fast moving est, so this might
like be an opportunity need to combine
transportation infrastructure with title energy
installations to actually have
small title power plants under a bridge. So
what have you learned from the project so
so far? What has the bridge told you?
My part of this project is underneath everything.
Above the water. Martin's part is everything below
the water or below the bridge I should
say. So from our side, this bridge is
a gus list steel trust bridge and it's
a movable bridge. So that means that the
vertical lift span, which weighs about a million
pounds
gives me a really
impact load
every half an hour from our Memorial Day,
which is in May till labor day in
August so all summer long. So I have
these really nice high impact loads. That give
me,
response data on how these gus list trust
connections are behaving. Also, the bridges is very,
s
So it's again a very elegant
profile, and 1 of the things we're looking
at is how is that vibration affected
by the fact that it was a much...
Broader, and much wider bridge, tower and now
it's much narrower tower. So we're... We collect
that data,
we're actually learned about this gus list trust
connection
its behavior in the field is really surpassing
all
expectations.
It's, a very robust connection. It allows for
load
distribution. We have matched that with data in
our lab where we have a, half... Scale
or a 1 to 2 scale model of
this gus list connection, which uses bent steel
fl
welded to a a web, a steel web,
and we put about 2000000 cycles at about
a hundred thousand pounds of tension, and nothing.
We saw no change in behavior.
We did very mean things to this connection.
We go out the wells on, 6 inches
on either side of the web We drilled
holes in areas that you don't want holes
in, and we're still seeing force
redistribution across.
That which gives the redundancy and me... Means
that that connection is a very robust connection.
That's probably from our side, the biggest,
takeaway has been, but, 1 of the other
things we've seen is we've seen no change
in behavior
when we added the title turbine and 1
of the big concerns that bridge owners had
when we started this project 10 years ago
is the bridge has so many demands on
it. What additional demand is this turbine going
to create. Am I going to have another
maintenance
issue is this going to put more demand
on my peers and what we've really seen
is that the force impact of having even
an operational termite
attached to this bridge pier is really in
the noise
of design elements in the... Other
demands that the bridge experiences. So that kind
of opens the door for as Martin had
mentioned, looking at these bridges as being opportunities,
for renewable energy
installations
because especially if you think of either a
wind turbine or a tidal turbine, the the
structure of that turbine
is meant that it shouldn't move. And the
bridge really has 1 really big job don't
move. So if you attach a turbine to
a bridge pair that's not supposed to move
anyways,
and we can put it in a location
where maybe it's not grid level energy, but
this distributed
energy
conversion system,
where instead of the bridge as Martin said
being something that's pulling power off the grid
something that's either putting power back in the
grid just depending on the array of turbines
that you have to deployed there, or at
least self sustaining. And I think our,
1 of our goals when we started this
project because we started this project right around
when super storm Sandy had hit New York
and New Jersey was that if we
had this... The title turbine that's installed at
the bridge,
If we had an extreme event where you
lost power that the energy created
by that turbine would be able to power
1 lift and this kind of goes back
to what we were talking about before that
bridges our obstruction to vessel traffic.
So really,
And in an extreme event, you would need
that bridge to be open to allow for
vessel traffic and,
a 1 way to harden our infrastructure,
not from a structural standpoint, but just from
a use a usability standpoint
and
that they have to allow for all different
traffic and That's what we've learned from the
bridge piece. Also, Martin has been able to
collect data about the the tides that are
running in. And some of the characteristics of
the water the water below, which was a
unique aspect of this project as well.
Martin, you wanna tell me a bit more
about, about
what you've learned from this project below below
the surface?
Yeah. Sure. Happy to. Just just to emphasize
the the... Drilling and guarding holes into the
steel that was in a model, not not
on the actual bridge. That wasn't the way
to clarify. Good to clarify.
Lab. So from from a title energy conversion
perspective,
we
have basically created a platform of opportunity where
we can, test turbines and do all sorts
of other important measurements about high
conversion and how it impact the environment. So
we've had a title turbine in there since,
2018.
We've got gathered
a lot of data on this in terms
of power and loads.
We've also done measurements
with acoustic sensors to see how much noise
this turbo adds to the to the aquatic
environment and it's x actually
much quieter than than the noise that's already,
in, this location due to it being, fairly
busy port So that was found to not
be a problem. We've also looked at, possible
interactions with with fish,
we haven't seen any.
That does not mean that they don't
can't occur, but we have not observed any
which is which is which is a good
thing now,
fish generally tend to stay away from,
these kind of structures and high turbulence areas
when when the currents are running fast,
and that's the only time this treble is
actually... It's actually rotating. It's rotating fairly slowly.
So the the... All we have in there
right now road rotate at about maybe 22.
30 Rpm. So we think it's a fairly
benign way to actually, convert some of the
kinetic energy. We've learned a lot about challenges
the debris and in the water and how
that interacts was true turbines and platforms.
And we've we've,
I guess, demonstrated enough
good things with this installation that it is
now becoming a a scaled title test site
funded by the department of Energy. 1 thing
we're working on currently is like a much
more instrument version of of a term building
a new that will go in
likely later this year or early next year.
Actually And that is in collaboration with several
national labs, Sand National laboratory,
National Noble Laboratory and Pacific Northwest National laboratory.
So this a lot of interest in understanding
how how this... How tight energy works, and
and then looking at in what locations, it
can actually be
could be built out, and and then be
implemented.
Our s is is a
comparatively small, but very energetic as tree, so
it's great for testing these things.
It is not a probably not a good
location to try to build this out to
larger installation
however, as you're put in new bridges,
you
should consider whether that makes sense to actually
cooperating.
You know, arrays of of these turbines under
the bridge in certain locations. And, Aaron and
I actually studied that with a number of
students a few years ago, and it it
turns out that if you
If you do this in a very modular
fashion and then have
once you get up to certain number of
devices install outside of the shipping lanes, it
actually is is
not such a terrible economic proposition anymore more
either.
Generally speaking,
any marine energy will be more expensive than
land based energy just because you're dealing with
this, you know, challenging environment that's cor,
and and you have to debris and other
another issues, so
possible flooding of of of electrical components and
such. So you have to look at the
value that it actually adds to having that,
which is in the case of tile energy.
It's its predictability and and having another energy
source that is available when, for example,
solar wind is is not
So do you think that this sort of,
living bridge project is is scalable Is it
something you'd like to see applied to other
bridges, you know kind of replacing the idea
that bridge inspection,
is,
is just something you do every 6 months
or every 6 years or whatever the regulatory
environment says. It's and also replacing the idea
that ab bridges a static thing that that
doesn't do anything other than conveyed traffic with
the idea that a bridge might be part
of... A solution should generate energy and might
least be self supporting in that sense. Is
that really scalable? Can you be... You imagine
it being implemented in other bridges around the
world around the country?
I would say I can. It is just
a question of how do you set this
up to to minimize the effort involved and
looking after. The same goes for for
ongoing bridge measurements. Right? So you can we
can put all the senses we want on
there and they give us great information. How
do you maintain that infrastructure you know, 10:20,
30 is down the road when you have
to upgrade systems? And can you really... Can
you really provide what a sort of a
good way to provide long term
structural health monitoring measurements and and and
and in the same vein, what is a
good way to provide
some long term
energy
addition to to title
to to est bridges
that does not require a
an immense amount of maintenance, which was sort
of, in, you know, kind of make it
make it not not so feasible way. So
that's all that's that's... Those are the hard
questions to to
to address
on how to actually make this work.
Aaron you would add to that? Yeah. I
think that 1 of the things that I
hope
as we see,
this last administration
actually created an office of transportation and energy.
So that was the first time we had
that,
where we see, you know, usually the secretary
of transportation and the secretary of energy is
actually a combined office. The goal of that
office was really about
electrification for electric vehicles, but I do hope
that that expands so that we, at least
in the United States and hopefully crossed the
world. It that we... That we get away
from that siloed use of of our different
assets, especially our public assets, so that our
transportation asset
could actually be, a, benefit to our... In
in our energy assets or in our communication.
We we do see that where you'll have
a bridge that will carry a water line
or it carries power lines or it carries
Dsl lines
from there. So really, that... That more intense
integration that actually happens not as an after,
kind of an aftermarket
integration, but something that happens during the planning
stages.
And that's
where this particular bridge, we were
we were aware. The the designer was aware
of our intent, but because the bridge was
AAA
replacement due to structural deficiency, the they... The
original bridge had been closed to structural deficiency,
So it was a very fast paste project
for its replacement.
We didn't have the opportunity to actually integrate
this turbine idea into the design to but
I think as Martin mentioned, if we are
integrating into the design, there's an opportunity that
it's not an add on to appear that
is. Actually integrated into the peer design,
so that if we're investing these this money
that we need to invest
because our our population needs to be able
to travel to have access to goods and
services
and,
work and school and all of those things.
That looking at those elements that are not
only a huge
resource in terms of dollars, but also environmental
impact
and have those those assets actually do more.
And I think 1 of the things is
being a support for a renewable energy installation
1 of the other things that, Martin and
I do with this project is this is
the only,
bridge across that particular river connecting Ports smith
and Kin. That has pedestrian access. So we've
done a lot of outreach with local schools.
Next week, we actually have 80 seventh grade
students coming in and we'll be talking about
a part of that discussion for them will
be about the bridge project. We have these
really,
great elements that are in,
our everyday lives. We cross bridges all the
time and really taking the time to explain
to that citizen engineer citizen scientists
what are the advances that are happening there
to really
promote that study of math and science? Whether
you're in middle school or high school or
becoming either a scientist or engineer as your
profession. And I think that's something we miss
out on a little bit, And, I mean,
who doesn't love bridges, really?
Well, Aaron Bell, and Martin Was, thank you
for in sharing your love of bridges and
and bridges fine, and the things you could
do with them with our audience. It's been
a real pleasure. Thank you. You know, Martin
didn't use to love them. He's learned to
love them. Yes. Learned got news. Yes. Fine
It's our pleasure. Thank you very much for
having. Thank you very much. Yeah.
I'm afraid that's all the time we have
for this week's podcast.
Thanks to Aaron Bell,
Martin Was. And Margaret Harris for a fascinating
discussion.
This podcast was produced by Callum J and
Fred Isles
So a special thanks to them both.
If you're a regular listener to the podcast,
you've probably noticed that we have a new
theme tune.
It's called 137,
and it was composed and performed by the
physicist
Philip Mori.
He talks about the significance of that number
and the creative process
involved in making the music
over on the Physics World stories podcast,
which you can listen to on the Physics
world website or at your favorite podcast
provider.
Just look for the headline
swift earthquakes
and new podcast
music
inspired by the fine structure constant.
And yes, we are talking about Taylor swift
and the seismic
activity
surrounding her concerts
with Jacqueline
Kaplan Hour ba, a s,