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(gentle music)

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- [Narrator] When bridges fail,

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it's most often because
of extreme flood events.

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Based on current bridge guidelines,

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designers consider the force of water

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on the bridge's substructures.

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But there is little information

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about how these hydrodynamic forces

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affect the superstructures,

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the components that
hold up the bridge deck.

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In part, this project,

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thanks to small scale
laboratory experiments,

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was designed to help reduce
the bridge failure risk

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on typical TxDOT bridge decks.

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- So the main objective of this research

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was to assess and evaluate
the superstructure

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of our bridge structures.

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Not to be confused with the substructure

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which is the piers,

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superstructure is gonna
be the beams and slabs.

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And to assess this in
conditions of flooding

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when the deck is being over
topped or barely over topped,

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and in high velocities.

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- What we are trying to
do or we have done here

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is to quantify these forces first,

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making sure that they
have a good understanding

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of these forces acting on the bridge

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and then look at the current
practices the techs thought

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and other state agencies have

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to countermeasure these forces.

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We look at almost 900 bridges

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around the riverine and
coastal areas of Texas.

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And then we came up with
a list of the forces

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that are acting on these bridges,

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the depth of the flow velocity,

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the actual situation that's
happening in the field.

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And then we tried to
simulate them in the lab

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over the bridges that are
scaled 50 times smaller

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than the actual size.

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- They built a scaled model 50 to one

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of our Texas configurations.

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We looked at our Texas
girders or Tex girders,

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which ride beams basically,
we looked at box beams,

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we looked at slab beams.
And we built models,

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not of all of them, but most of them,

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with the idea that we would
also build CFD 3D modeling.

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- We brought all those
results to come to simulation,

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we call it the CFD,
Computational Fluid Dynamics,

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and then we ran more scenarios,
almost 1000 scenarios,

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to simulate the forces
acting on the bridge

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and the interaction between
the bridge superstructure,

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meaning the deck, and the substructures.

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And also we simulate the
countermeasures, the shear keys

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and earwalls to see if
they have enough capacity

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to counteract the flood force.

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- The drag forces are a little greater

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than the structural shear key strengths.

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That's an indication

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that we can probably improve our designs.

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And so that's the next step
is to improve our details

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and our standards for bridge design.

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- Using the result of this
simulation on our recommendation,

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we can make the existing bridges safer

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and also we can incorporate
this design recommendation

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into future bridges,

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and basically we have safer
bridges in our system.

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- We want to build a
system that's reliable,

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that doesn't have maintenance issues

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or fail during large storms.

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We want a safe system, and
we want an economical system.

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- [Announcer] For more information

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and to find the publications
for this project,

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please visit the tex.researchlibrary

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at the link shown below.