(gentle music)
- [Narrator] When bridges fail,
it's most often because of extreme flood events.
Based on current bridge guidelines,
designers consider the force of water
on the bridge's substructures.
But there is little information
about how these hydrodynamic forces
affect the superstructures,
the components that hold up the bridge deck.
In part, this project,
thanks to small scale laboratory experiments,
was designed to help reduce the bridge failure risk
on typical TxDOT bridge decks.
- So the main objective of this research
was to assess and evaluate the superstructure
of our bridge structures.
Not to be confused with the substructure
which is the piers,
superstructure is gonna be the beams and slabs.
And to assess this in conditions of flooding
when the deck is being over topped or barely over topped,
and in high velocities.
- What we are trying to do or we have done here
is to quantify these forces first,
making sure that they have a good understanding
of these forces acting on the bridge
and then look at the current practices the techs thought
and other state agencies have
to countermeasure these forces.
We look at almost 900 bridges
around the riverine and coastal areas of Texas.
And then we came up with a list of the forces
that are acting on these bridges,
the depth of the flow velocity,
the actual situation that's happening in the field.
And then we tried to simulate them in the lab
over the bridges that are scaled 50 times smaller
than the actual size.
- They built a scaled model 50 to one
of our Texas configurations.
We looked at our Texas girders or Tex girders,
which ride beams basically, we looked at box beams,
we looked at slab beams. And we built models,
not of all of them, but most of them,
with the idea that we would also build CFD 3D modeling.
- We brought all those results to come to simulation,
we call it the CFD, Computational Fluid Dynamics,
and then we ran more scenarios, almost 1000 scenarios,
to simulate the forces acting on the bridge
and the interaction between the bridge superstructure,
meaning the deck, and the substructures.
And also we simulate the countermeasures, the shear keys
and earwalls to see if they have enough capacity
to counteract the flood force.
- The drag forces are a little greater
than the structural shear key strengths.
That's an indication
that we can probably improve our designs.
And so that's the next step is to improve our details
and our standards for bridge design.
- Using the result of this simulation on our recommendation,
we can make the existing bridges safer
and also we can incorporate this design recommendation
into future bridges,
and basically we have safer bridges in our system.
- We want to build a system that's reliable,
that doesn't have maintenance issues
or fail during large storms.
We want a safe system, and we want an economical system.
- [Announcer] For more information
and to find the publications for this project,
please visit the tex.researchlibrary
at the link shown below.