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- Reinforced concrete
inverted T bridge caps

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or IBCs are widely used in Texas bridges.

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They provide a way to increase
vertical clearance while

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having a pleasing appearance
for people on the road.

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In cases where two roads are
not aligned perpendicularly,

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IBCs may be skewed,
creating a torsion effect.

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That could lead to
cracking and future costs

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to repair any damage.

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The Texas Department of Transportation,

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working with the University of Houston,

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ran tests to explore if
the skewed arrangement

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of transverse reinforcements
leads to weakening

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or changing the performance of ITBCs.

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- Traditional design, the
transverse reinforcement,

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is perpendicular to the
access of the banker,

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but we have problems
if we have skew banker.

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How do we design this region?

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- If we were to skew all
the transverse reinforcing

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or stirrups to match the bridge skew,

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the designer could detail one bar type

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and simplify construction,

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and also help maintain
a consistent spacing

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along the length of the cap.

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Astro did not provide any design
guidance for this approach,

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which led us to this research project.

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- We did our lab test first,
perform structure testing

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to see what's the structure performance.

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Well, we found skew reinforcing
the structure performance

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is even better than traditional design.

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Therefore, text suggested
to do implementation,

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and then we work on a real bridge.

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- Finally, we implemented the new design

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on one of our new bridges.

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The team installed
structural monitoring sensors

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and conducted a full-scale
load test on our new bridge.

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- Now, we proposed the skew reinforcement

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that has simplified the design

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and also make the construction easier.

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That will make the project leaner,

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project become cost
effective and time saving.

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- By skewing the stirrups
along the inverted T cap,

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if we result in faster construction

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and we have less chance of
having cracking in the caps,

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the traveling public will be impacted less

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as we can build the bridge faster

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and we don't have to go back out there

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and possibly repair the bridge

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because of cracks in the future.

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Long term, the cap is more resilient

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to cracking under our service loads.

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This equates to longer lasting bridges,

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which is a win for everybody.

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- For more information

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and to find the publications
for this project,

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please visit the Tex.Research Library

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at the link shown below.