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(dramatic music)

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- [Narrator] Pre-stressed concrete beams

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are used in many bridges across Texas.

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The American Association of State Highway

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and Transportation Officials, or AASHTO,

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provides strength
requirements for these beams

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based on past tests,

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but advancements in concrete materials

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have brought about the need to
reexamine the specifications.

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The Texas Department of Transportation

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and researchers with Texas A&M University

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have looked at the minimum
sheer reinforcement requirements

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for pre-stressed concrete beams
to determine their accuracy

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and develop design guidelines
that could lower costs

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and speed up bridge construction.

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- As we progress in the field

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and we have new materials, for example,

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high-strength concrete, we
have high-strength steel,

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also, we have larger members,
larger cross sections,

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there is a natural need to reevaluate

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if those requirements
that have been based on,

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I would say, older designs are still valid

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or if we should look at
those again and refined.

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- So we felt it is needed
to take the advantage

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of this advancement to revisit

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the minimum share enforcement requirement

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that we use to design or
enforce concrete beams.

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If we are able to do that,

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that could lead to significant savings,

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and that can also help us
to have a better approach

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in designing of bridges
in the state of Texas.

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- There was one part of the research

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that was data analysis
and model development,

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so that was essentially
analyzing a database.

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The other part was
finite element analysis,

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because we realize that we
need to expand our database

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and we realize that we definitely
need to do some testing.

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However, the testing
is much more expensive,

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so we need to be careful
to select, to investigate,

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I would say, the most
important variations.

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So a portion of this extra case evaluation

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was done in the lab,
and we test, actually,

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22 designs in 11 girders, and
these girders were quite big,

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so we're talking about 50-feet
long girders on average,

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so quite large specimens.

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In addition to that,

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we developed finite
element analysis models,

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where we calibrated them
with existing test data

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and then we used them to run analysis

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on cases which were not in the database,

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but were not in the lab either.

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- In test docs, as we continue
to strive for quality,

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as we continue to improve
and fine tune our process

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of designing bridges,

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we continually make
use of research effort,

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and from that research, we can
come back in the department

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to refine those research outcome

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and see how we can implement it,

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because this implementation
will bring a lot of cost saving

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in terms of dollar cost,

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and also in terms of road user cost,

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and in terms of a delay that
are typically being observed

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during bridge construction
across the state.

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So that is the major
benefit of this research,

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and it is a continuous effort

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that we'll continue to improve on.

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- [Narrator] 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.