(gentle music)
- [Narrator] Closure joints are essential in the technique
of accelerated bridge construction or ABCs.
These structures require materials that cure
and gain strength quickly
while maintaining long-term durability.
The Texas Department of Transportation
and the Center for Transportation Research
develop high performance mix designs
with a focus on strength
and durable closure joints that will speed up the time
a structure can begin receiving traffic.
- The way that Texas has been moving
is we want construction done faster
and road closures shortened
to reduce the impact on the traveling public.
- This research was driven by the need
to be able to reconstruct bridges,
especially in highly congested areas
and what's called accelerated bridge construction
or ABC projects.
And the whole goal and the big picture
is to be able to essentially come in over a weekend
and replace a bridge
by casting most of the bridge itself offsite,
and then have it delivered over the weekend,
right after the demolition of the superstructure,
erect the entire bridge.
And the goal would be to open
that bridge back on Monday morning, for instance.
- [Narrator] Creating the bridge off side
and bringing those pieces on
during construction can help speed up the process,
by having the bridge partially built beforehand,
construction time is reduced greatly.
- [Speaker] And then our focus was primarily
just the closure pores,
which are basically six inch width sections
of fiber reinforced concrete
to essentially stitch the bridge together.
- The most important finding from this research project
has been the mixture type
requested of what is called UHPC,
which is ultra high performance concrete.
And this type of concrete will cure faster,
cure stronger than typical concrete.
- Most important thing we found
is that the technology is viable.
We were able to demonstrate that in the lab,
but more importantly, we demonstrated it by tracking
and monitoring two different bridges
that TxDOT was in the process
of designing and constructing,
and our team was involved in instrumentation,
monitoring of those bridges
over the course of a couple of years.
- [Speaker] By monitoring bridges during use
by normal traffic loading, we're able to see the stresses
and forces that go into these joints
and allow us to see how these joints are performing,
whether they're getting over stress and cracking too much
or if they're performing well during the stress
of normal traffic.
- [Narrator] For more information
and to find the publication for this project,
please visit the TxDOT Research Library
at the link shown below.