good evening how many potholes have you
run over in the past week or debris that
you had to maneuver your car around to
try to stay safe or that construction
zone that’s been under construction for
the past year well we know we have a
serious problem today I’m going to talk
to you about our nation’s infrastructure
particularly our bridges and how myself
a structural engineer is working to
engineer sustainable bridges we have
more than 600,000 bridges in the United
States however the state of them is
under concern the average bridge is
approximately 43 years old so if we
break that down that means four out of
every ten bridges is approximately 50
years old there are a hundred over a
hundred and eighty eight million trips
that are taken daily across deficient
bridges it makes you at wonder and beg
the question how many of you have driven
over them in 2016 the data show that 9
percent of the nation’s bridges were
structurally deficient where we defined
structural deficiency as one or more
deficiencies that a bridge might have
that needs special attention so the way
things work is that once every two years
a bridge is inspected to make sure that
it’s okay
what we’ve noted that there are some
serious problems in California alone we
see the largest number in an urban
environment with structurally deficient
bridges more than 87% of these bridges
in California are structurally deficient
so what does that look like well let’s
take a look at our infrastructure report
card for America I know you see a lot of
season deeds what if you brought home a
report card to a parent or someone who
is funding your education it definitely
raises the question so we for the survey
for the infrastructure report card we
see aviation earned a grade of D where
US airports serve 2 million passengers
daily
a degrade wastewater D+ knowing that the
demand of wastewater and treatment
plants will grow more than 23 percent by
2032 dams D schools D plus where 53
percent of schools need improvements to
reach good conditions so now we move on
to the bridges C – again 10% of these
bridges are rated to be structurally
deficient where America’s overall grade
is a d+ that definitely raises a concern
to me so this is where you come in our
current user pays about eighteen point
four cents per gallon for gasoline and
twenty four point four cents per gallon
for diesel this translates to that we
have this highway tax fund that we’re
trying to increase these prices because
we know that the investment in our
infrastructure is in sufficient and this
is where you come in so we talked about
these bridges and we see every year we
put these de-icing salts on our roadways
and we know that these the icing salts
will corrode these bridges we know
chemically that when we put salts on
roads that lowers the freezing point for
any fallen snow or rain such that it
would not freeze so it makes you wonder
we build these bridges we put these
socks on them to make them deteriorate
and then we have to repair them again
does that make sense well I thought the
same thing too so how do we move forward
to address this issue well we know it’s
going to take more funding we know it’s
going to take leadership we know it’s
going to take proper planning and
moreover it’s going to take innovation
and that’s where one day I said Monique
how can we make our bridges better to me
it doesn’t make sense we build tear it
down me more money have to build it
again so I said there has to be a better
way that we can use engineering to
design or bridges better so that’s what
I did so close your eyes for a
it can you imagine a bridge without
steel and you can open your eyes well
that’s what I did I got some funding for
research to really look at bridges and
how we can design them better using
composite materials these composites are
made out of fibers and resin that are
pulled treated together to be really
strong in fact just as strong as steel
they have advantages of being more
flexible stronger and more durable
because the main issue is if we put
these salts on the road it goes down and
affects the steel that are within these
concrete structures the deteriorates and
the repeat this cycle so if we have
something that is corrosion resistant
where in the bottom left shows a picture
of these bars that are like rods that
can replace the steel if we can replace
them and engineer them in a way that
they can work just as well we can look
at longer life spans for these bridges
longer than 50 years so yes the
investment using these composite or
fiber reinforced polymer FRP bars cost a
little bit more money on the front end
but in the lifecycle cost it would be
more manageable and we won’t be
replacing bridges every 5-10 years and
at the rate we’re going where we’re
already a hundred and twenty three
billion dollars in the hole of where we
need to be to keep up with repairs so
the concept is for bridge deck if you
think about on the red those are what
you would typically see for the steel
bars that they’re inlaid in there to
make sure that it carries the tension
where steel is very strong and touching
and we have it coupled with the concrete
which is very strong and pressure
compression when you squeeze on it so my
whole idea was nothing novel but let’s
just use these composite bars on the
inside of a bridge deck lay on like a
lattice structure or a matrix on top of
each other pull on some of them so that
they’re really strong in their optimal
capacity and tension then pour the
concrete in and see how these things
perform there are some challenges with
any good system we have to look
critically at how the whole system works
but these bars themselves have a high
strength to self-weight ratio about 10
to 15 times that of Steel like
said their conversion resistant
non-magnetic and non-conducting it’s a
no-brainer is what I thought they also
have excellent fatigue characteristics
in other words if you cycle them back
and forth they can go for longer periods
of time which is ideal for the bridge
environment so the whole concept is we
have these bridge decks we put them
together like Legos we connect them with
concrete to tie it all together but to
way in which we have to use this system
in the long ways on the bridge deck we
actually pull the bars in tension so
where we have there the dead end that’s
where we actually lock in the bars on
that one end and pull from the other end
which is called the live end to stretch
out these bars you can think of it like
a rubber band we stretch it really
really taut and then we pour the
concrete in to basically seal it all
together to make it this one great
system
another advantage in which the Federal
Highway is also moving towards is what
we call these prefabricated bridge
elements and systems in other words
these panels are perfect in the sense
that we can put them make them off-site
in a lab or a manufacturing plan or a
precast plant and then put them on a
truck take them to the bridge site and
then lay them in like Legos and then
connect it all with a concrete so the
idea that it would take less time for
construction and also be very efficient
so with these bars we also learn that
there are some thermal plastic
properties that make these bars great so
one of the challenges with having these
bars or composites we know they’re
flexible but will we be able to bend
them like we can steel so that we can
make hooks well yes you can we can heat
it up we can hit on it with a slight
loss of the cross sectional area and
then we can bend it so what advantage
does this have well it’s a significant
advantage in that we can have these bars
also serve as hooks when we put the two
panels together and need to connect it
with a concrete in between so right here
you’re seeing a picture
on the inside view of looking at these
bars that are these stirrups or hooks
that we need to connect these bridge
decks together and tie them together
with either a grouse or high performance
concrete so the question becomes will
build this system how will it work well
that’s what we did through the research
that I got through NSF we were able to
test this bridge deck system so it’s
about 10 feet by 12 feet a nice sized
bridge deck where you can see the yellow
bars in the long direction or sticking
out and those are the ones that were
pulled really really strong
the other ones perpendicular to it were
laid to give that lattice structure so
in doing so we actually loaded down on
the bridge deck just how we would mimic
the loads from a truck on a bridge where
we looked at several different cases I
mainly focus on low cases one where we
have two wheels or a truck load wheels
behind each other and also low case 5
which is on the outer edge or what we’re
considering there overhang in other
words with that load simulates is if you
have a barrier on a concrete bridge and
then you have either impact from a truck
or something what’s that overturning
moment or that force that needs to be
resistant so we tested these we had our
control specimen that was made out of
steel that was embedded in the concrete
as well as of the bridge deck system
what you saw which actually had the
fiber bars that were pre-stressed or
just pulled like a rubber band as well
as the other bars going perpendicular to
that so the solid line shows the aramid
fiber reinforced polymer specimen or the
composite specimen and then the control
specimen is the one that’s the dotted
line we see that we were looking at just
load in the vertical axis versus
displacement on the horizontal axis that
the composite a FRP specimen actually
took larger loads it was quite strong
quite durable we were very pleased with
that and that was for low case one and
we had the loads on the inside of the
bridge or the top bar right picture
where you can actually see that not only
were the stresses on the loads
transferred nicely but it took a larger
load
that’s a win-win in my book we took a
step further and looked at the case
where we actually have low case five
showing here where we have the control
specimen as the dotted line and then the
solid black line as the composite
specimen so this is the worst case
scenario that if you were to have a
truck or something that go off the edge
how much resistance would you get by the
system we see that the FRP specimen the
fiber reinforced polymer composites
didn’t do too badly we see this because
the bars are quite flexible this
softening system where it still exceeds
that minimum threshold for the load of
200 kilonewtons so we had successful
results with a bridge deck and like I
asked earlier when I was thinking how
can we do this better I extended it from
bridge decks to also working on now
let’s put these FRP bars into a column
to kind of go with this whole notion of
this semi medalists bridge system so we
can address this major issue of
corrosion so at Morgan State University
I’ve had several students and doctoral
students working on this work where
we’ve taken it a step further that
innovation piece where we have these
bars that are addressing the issue of
corrosion check got that but we also
know that in several environments these
columns must also take some type of
lateral loads or may be loads induced by
earthquakes which is a significant issue
we actually know that two of the largest
earthquakes that happen in the United
States happen in 1811 and 1812 in New
Madrid Missouri right that’s not on the
west coast the second one in 1886 in
Charleston South Carolina we have
different types of earthquakes on the
East Coast so while we are dressed also
this issue of corrosion I thought let’s
also take it a step further and how we
can build columns that are resistant to
also absorb energy and can rock but at
very low levels but still also be
resistant so that’s what we’re doing at
Morgan State University we’re innovating
we’re engineering systems to make them
better and more sustainable to help
America’s infrastructure that’s the
first phase
the second phase is that we’re going to
shake it up a little bit we have a shake
table that allows us to simulate
earthquakes the table is about 9 feet by
9 feet we can mathematically input
equations into the driving system and
make this thing shake as if it were like
a magnitude 8 or 9 earthquake at Morgan
State University so we’re really excited
to expand this research on this step
further to look at the dynamic loads so
that we can put this all together and
model it so this is a picture of what
the physical lab looks like in real real
time with our strong floor and strong
wall for which we’ll push and pull to
simulate that softer rocking for that
column and then in the face – we’re
going to put it on the table and shake
it to also see its performance so the
question becomes how do we really move
forward I have this idea to be
innovative and to really try to engineer
a more sustainable solution but the fact
of the matter is it takes time and it
takes a paradigm shift especially with
the construction industry to accept
these different practices and say yes
this is something that’s more
sustainable because we all can agree I’m
sure that if we build something use your
taxpayer money to put salt on it then
have to build it back up just doesn’t
make sense but we know we have a long
way to go but the hope is that as we
move forward that will address these
issues and also look at issues of asset
management not only as we inspect the
bridges and figuring out which bridge
needs more help but also to prioritize
well which one needs more help first so
we don’t see bridge collapses like we’ve
seen in the past or significant lives
were lost
thirdly we also need to work on
converting research to practice of
having more implementation projects
where we’ve had full-scale projects in
the laboratory but also having more
field demonstrations which would also
help to move this forward as well as
policy so with that I thank you and I
just I’m glad to have shared my
experience on how we’ve engineered
better bridges thank you
[Applause]
run over in the past week or debris that
you had to maneuver your car around to
try to stay safe or that construction
zone that’s been under construction for
the past year well we know we have a
serious problem today I’m going to talk
to you about our nation’s infrastructure
particularly our bridges and how myself
a structural engineer is working to
engineer sustainable bridges we have
more than 600,000 bridges in the United
States however the state of them is
under concern the average bridge is
approximately 43 years old so if we
break that down that means four out of
every ten bridges is approximately 50
years old there are a hundred over a
hundred and eighty eight million trips
that are taken daily across deficient
bridges it makes you at wonder and beg
the question how many of you have driven
over them in 2016 the data show that 9
percent of the nation’s bridges were
structurally deficient where we defined
structural deficiency as one or more
deficiencies that a bridge might have
that needs special attention so the way
things work is that once every two years
a bridge is inspected to make sure that
it’s okay
what we’ve noted that there are some
serious problems in California alone we
see the largest number in an urban
environment with structurally deficient
bridges more than 87% of these bridges
in California are structurally deficient
so what does that look like well let’s
take a look at our infrastructure report
card for America I know you see a lot of
season deeds what if you brought home a
report card to a parent or someone who
is funding your education it definitely
raises the question so we for the survey
for the infrastructure report card we
see aviation earned a grade of D where
US airports serve 2 million passengers
daily
a degrade wastewater D+ knowing that the
demand of wastewater and treatment
plants will grow more than 23 percent by
2032 dams D schools D plus where 53
percent of schools need improvements to
reach good conditions so now we move on
to the bridges C – again 10% of these
bridges are rated to be structurally
deficient where America’s overall grade
is a d+ that definitely raises a concern
to me so this is where you come in our
current user pays about eighteen point
four cents per gallon for gasoline and
twenty four point four cents per gallon
for diesel this translates to that we
have this highway tax fund that we’re
trying to increase these prices because
we know that the investment in our
infrastructure is in sufficient and this
is where you come in so we talked about
these bridges and we see every year we
put these de-icing salts on our roadways
and we know that these the icing salts
will corrode these bridges we know
chemically that when we put salts on
roads that lowers the freezing point for
any fallen snow or rain such that it
would not freeze so it makes you wonder
we build these bridges we put these
socks on them to make them deteriorate
and then we have to repair them again
does that make sense well I thought the
same thing too so how do we move forward
to address this issue well we know it’s
going to take more funding we know it’s
going to take leadership we know it’s
going to take proper planning and
moreover it’s going to take innovation
and that’s where one day I said Monique
how can we make our bridges better to me
it doesn’t make sense we build tear it
down me more money have to build it
again so I said there has to be a better
way that we can use engineering to
design or bridges better so that’s what
I did so close your eyes for a
it can you imagine a bridge without
steel and you can open your eyes well
that’s what I did I got some funding for
research to really look at bridges and
how we can design them better using
composite materials these composites are
made out of fibers and resin that are
pulled treated together to be really
strong in fact just as strong as steel
they have advantages of being more
flexible stronger and more durable
because the main issue is if we put
these salts on the road it goes down and
affects the steel that are within these
concrete structures the deteriorates and
the repeat this cycle so if we have
something that is corrosion resistant
where in the bottom left shows a picture
of these bars that are like rods that
can replace the steel if we can replace
them and engineer them in a way that
they can work just as well we can look
at longer life spans for these bridges
longer than 50 years so yes the
investment using these composite or
fiber reinforced polymer FRP bars cost a
little bit more money on the front end
but in the lifecycle cost it would be
more manageable and we won’t be
replacing bridges every 5-10 years and
at the rate we’re going where we’re
already a hundred and twenty three
billion dollars in the hole of where we
need to be to keep up with repairs so
the concept is for bridge deck if you
think about on the red those are what
you would typically see for the steel
bars that they’re inlaid in there to
make sure that it carries the tension
where steel is very strong and touching
and we have it coupled with the concrete
which is very strong and pressure
compression when you squeeze on it so my
whole idea was nothing novel but let’s
just use these composite bars on the
inside of a bridge deck lay on like a
lattice structure or a matrix on top of
each other pull on some of them so that
they’re really strong in their optimal
capacity and tension then pour the
concrete in and see how these things
perform there are some challenges with
any good system we have to look
critically at how the whole system works
but these bars themselves have a high
strength to self-weight ratio about 10
to 15 times that of Steel like
said their conversion resistant
non-magnetic and non-conducting it’s a
no-brainer is what I thought they also
have excellent fatigue characteristics
in other words if you cycle them back
and forth they can go for longer periods
of time which is ideal for the bridge
environment so the whole concept is we
have these bridge decks we put them
together like Legos we connect them with
concrete to tie it all together but to
way in which we have to use this system
in the long ways on the bridge deck we
actually pull the bars in tension so
where we have there the dead end that’s
where we actually lock in the bars on
that one end and pull from the other end
which is called the live end to stretch
out these bars you can think of it like
a rubber band we stretch it really
really taut and then we pour the
concrete in to basically seal it all
together to make it this one great
system
another advantage in which the Federal
Highway is also moving towards is what
we call these prefabricated bridge
elements and systems in other words
these panels are perfect in the sense
that we can put them make them off-site
in a lab or a manufacturing plan or a
precast plant and then put them on a
truck take them to the bridge site and
then lay them in like Legos and then
connect it all with a concrete so the
idea that it would take less time for
construction and also be very efficient
so with these bars we also learn that
there are some thermal plastic
properties that make these bars great so
one of the challenges with having these
bars or composites we know they’re
flexible but will we be able to bend
them like we can steel so that we can
make hooks well yes you can we can heat
it up we can hit on it with a slight
loss of the cross sectional area and
then we can bend it so what advantage
does this have well it’s a significant
advantage in that we can have these bars
also serve as hooks when we put the two
panels together and need to connect it
with a concrete in between so right here
you’re seeing a picture
on the inside view of looking at these
bars that are these stirrups or hooks
that we need to connect these bridge
decks together and tie them together
with either a grouse or high performance
concrete so the question becomes will
build this system how will it work well
that’s what we did through the research
that I got through NSF we were able to
test this bridge deck system so it’s
about 10 feet by 12 feet a nice sized
bridge deck where you can see the yellow
bars in the long direction or sticking
out and those are the ones that were
pulled really really strong
the other ones perpendicular to it were
laid to give that lattice structure so
in doing so we actually loaded down on
the bridge deck just how we would mimic
the loads from a truck on a bridge where
we looked at several different cases I
mainly focus on low cases one where we
have two wheels or a truck load wheels
behind each other and also low case 5
which is on the outer edge or what we’re
considering there overhang in other
words with that load simulates is if you
have a barrier on a concrete bridge and
then you have either impact from a truck
or something what’s that overturning
moment or that force that needs to be
resistant so we tested these we had our
control specimen that was made out of
steel that was embedded in the concrete
as well as of the bridge deck system
what you saw which actually had the
fiber bars that were pre-stressed or
just pulled like a rubber band as well
as the other bars going perpendicular to
that so the solid line shows the aramid
fiber reinforced polymer specimen or the
composite specimen and then the control
specimen is the one that’s the dotted
line we see that we were looking at just
load in the vertical axis versus
displacement on the horizontal axis that
the composite a FRP specimen actually
took larger loads it was quite strong
quite durable we were very pleased with
that and that was for low case one and
we had the loads on the inside of the
bridge or the top bar right picture
where you can actually see that not only
were the stresses on the loads
transferred nicely but it took a larger
load
that’s a win-win in my book we took a
step further and looked at the case
where we actually have low case five
showing here where we have the control
specimen as the dotted line and then the
solid black line as the composite
specimen so this is the worst case
scenario that if you were to have a
truck or something that go off the edge
how much resistance would you get by the
system we see that the FRP specimen the
fiber reinforced polymer composites
didn’t do too badly we see this because
the bars are quite flexible this
softening system where it still exceeds
that minimum threshold for the load of
200 kilonewtons so we had successful
results with a bridge deck and like I
asked earlier when I was thinking how
can we do this better I extended it from
bridge decks to also working on now
let’s put these FRP bars into a column
to kind of go with this whole notion of
this semi medalists bridge system so we
can address this major issue of
corrosion so at Morgan State University
I’ve had several students and doctoral
students working on this work where
we’ve taken it a step further that
innovation piece where we have these
bars that are addressing the issue of
corrosion check got that but we also
know that in several environments these
columns must also take some type of
lateral loads or may be loads induced by
earthquakes which is a significant issue
we actually know that two of the largest
earthquakes that happen in the United
States happen in 1811 and 1812 in New
Madrid Missouri right that’s not on the
west coast the second one in 1886 in
Charleston South Carolina we have
different types of earthquakes on the
East Coast so while we are dressed also
this issue of corrosion I thought let’s
also take it a step further and how we
can build columns that are resistant to
also absorb energy and can rock but at
very low levels but still also be
resistant so that’s what we’re doing at
Morgan State University we’re innovating
we’re engineering systems to make them
better and more sustainable to help
America’s infrastructure that’s the
first phase
the second phase is that we’re going to
shake it up a little bit we have a shake
table that allows us to simulate
earthquakes the table is about 9 feet by
9 feet we can mathematically input
equations into the driving system and
make this thing shake as if it were like
a magnitude 8 or 9 earthquake at Morgan
State University so we’re really excited
to expand this research on this step
further to look at the dynamic loads so
that we can put this all together and
model it so this is a picture of what
the physical lab looks like in real real
time with our strong floor and strong
wall for which we’ll push and pull to
simulate that softer rocking for that
column and then in the face – we’re
going to put it on the table and shake
it to also see its performance so the
question becomes how do we really move
forward I have this idea to be
innovative and to really try to engineer
a more sustainable solution but the fact
of the matter is it takes time and it
takes a paradigm shift especially with
the construction industry to accept
these different practices and say yes
this is something that’s more
sustainable because we all can agree I’m
sure that if we build something use your
taxpayer money to put salt on it then
have to build it back up just doesn’t
make sense but we know we have a long
way to go but the hope is that as we
move forward that will address these
issues and also look at issues of asset
management not only as we inspect the
bridges and figuring out which bridge
needs more help but also to prioritize
well which one needs more help first so
we don’t see bridge collapses like we’ve
seen in the past or significant lives
were lost
thirdly we also need to work on
converting research to practice of
having more implementation projects
where we’ve had full-scale projects in
the laboratory but also having more
field demonstrations which would also
help to move this forward as well as
policy so with that I thank you and I
just I’m glad to have shared my
experience on how we’ve engineered
better bridges thank you
[Applause]
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