- Reinforced concrete inverted T bridge caps
or IBCs are widely used in Texas bridges.
They provide a way to increase vertical clearance while
having a pleasing appearance for people on the road.
In cases where two roads are not aligned perpendicularly,
IBCs may be skewed, creating a torsion effect.
That could lead to cracking and future costs
to repair any damage.
The Texas Department of Transportation,
working with the University of Houston,
ran tests to explore if the skewed arrangement
of transverse reinforcements leads to weakening
or changing the performance of ITBCs.
- Traditional design, the transverse reinforcement,
is perpendicular to the access of the banker,
but we have problems if we have skew banker.
How do we design this region?
- If we were to skew all the transverse reinforcing
or stirrups to match the bridge skew,
the designer could detail one bar type
and simplify construction,
and also help maintain a consistent spacing
along the length of the cap.
Astro did not provide any design guidance for this approach,
which led us to this research project.
- We did our lab test first, perform structure testing
to see what's the structure performance.
Well, we found skew reinforcing the structure performance
is even better than traditional design.
Therefore, text suggested to do implementation,
and then we work on a real bridge.
- Finally, we implemented the new design
on one of our new bridges.
The team installed structural monitoring sensors
and conducted a full-scale load test on our new bridge.
- Now, we proposed the skew reinforcement
that has simplified the design
and also make the construction easier.
That will make the project leaner,
project become cost effective and time saving.
- By skewing the stirrups along the inverted T cap,
if we result in faster construction
and we have less chance of having cracking in the caps,
the traveling public will be impacted less
as we can build the bridge faster
and we don't have to go back out there
and possibly repair the bridge
because of cracks in the future.
Long term, the cap is more resilient
to cracking under our service loads.
This equates to longer lasting bridges,
which is a win for everybody.
- For more information
and to find the publications for this project,
please visit the Tex.Research Library
at the link shown below.