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- There are numerous reasons
why cracking can occur

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on bridge decks.

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Engineers must look at numerous factors

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in the design process

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to prevent and repair this type of damage.

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The bridge design standards involving

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how the concrete panels

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and steel girders are configured,

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play an important role in
preventing cracking damage,

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in what's called the Negative
Moment Regions of the bridge.

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A Negative Moment Region is the area

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of the deck just above
the interior supports

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of both continuous concrete
and steel girder bridges.

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During a recently completed
implementation project

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conducted at the University of Texas,

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Center For Transportation Research,

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researchers worked with TxDOT to develop

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and test a new design methodology.

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It's designed to help the engineer

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achieve the right steel content

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for preventing deck cracking,

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while also meeting the design requirements

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for these types of bridges.

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- And so we did the research
to help us identify exactly

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how much reinforcement we needed

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in this area to help control the cracking,

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and improve the durability
of our concrete decks.

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They implemented the
knowledge they gained,

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by changing the reinforcement
over the vents in the slab,

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on a project in Austin,

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and then monitored it afterwards

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and did some mud load testing

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by driving dump trucks across the bridge.

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- We worked with the engineer of record

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to actually vary the
design of the deck steel.

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And the, essentially we
had four different regions

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that we actually were able
to, to vary on that project.

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So we were able to get data from that,

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that specifically showed
the actual performance

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in a concrete bridge.

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That what we were missing on that was

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the behavior of what would
happen in a steel bridge.

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So we had a bridge of out in Bastrop,

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and again working with the
project monitoring committee,

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we vary the reinforcing
steel in that deck to again

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give us very novel data on the
behavior of the deck cracking

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as the function of that amount of steel.

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Our design methodology that
was developed by George G,

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who was the PhD student on this project,

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really allows an engineer to get in,

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and really customize
their design to achieve

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whatever the surface ability
requirements that they're

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they're actually wanting to get.

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- Now that we have this
information, we're gonna update

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our bridge design manual,

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and our details to fully implement it.

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So on future projects, we're
getting the right amount

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of reinforcement in these
negative moment regions.

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- [Speaker] For more information,

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and to find the publications
for this project,

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please visit the TxDOT research library

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at the link shown below.