Bridge engineers
are seeking new ways to build better bridges, reduce work zone travel delays, and reduce
maintenance costs. Agencies are challenged with replacing critical bridge components
with minimum disruption to the traveling public. Using ultra high performance concrete, or
UHPC, for precast panels and connection details is a new application that offers great potential
for new and rehabilitation bridge projects around the country. Wapello County, Iowa was
familiar with UHPC and saw its potential. With the help of an FHWA Highways for LIFE
Technology Partnerships grant to Coreslab Structures, they used UHPC waffle design modular
panels and UHPC connections for their Little Cedar Creek bridge project. The bridge consists
of 14 waffle slabs. The bridge deck panels were manufactured with UHPC and were installed
with field cast UHPC connections for bridge deck continuity. The design is simple, manufacturing
is easy, and construction moves quickly. The lightweight panels will allow rehabilitation
without needing to strengthen the substructure to handle heavier live loads. It also will
be possible to rehabilitate a bridge under traffic by replacing one lane at a time. Dean
Bierwagen: The main and - advantages of ultra high performance concrete is - is you have
a very high compressive strength compared to regular concrete, very high compressive
strength; 30,000 psi. So that is one - one big advantage. The next advantage, because
of the the mix that you have a a mix that s very low in permeability; basically waterproof.
I mean it s not going to let any water in. And then the third advantage, which for us
is another big positive for bridge decks, is the durability. I mean this stuff is very
durable under traffic and stuff. It ll, it ll hold together for a long time, I d say
as compared to regular concrete. A decade of research and deployment efforts have demonstrated
that UHPC is a material capable of future deployment in large scale applications. Field-cast
UHPC connections facilitate the use of conventional prefabricated components throughout bridges
by eliminating the weak links common to this type of construction. Due to concrete s longevity,
its efficiency in handling heavier live loads, and the economy with which structures can
be built in a short time, UHPC can enhance future projects around the country. Brian
P. Moore: The advice I d give to other owners and contractors would be to consider the material.
Consider to your application that you re needing. It s new; it s innovative. But it has a very
big potential. So, just don t rule it out because it s new. Give it a serious consideration
for the unique application that you need. Utilize the properties of the material and
give it some consideration as you look forward to look forward to building new projects.
And building products that will extend the life longer bridges, longer life, lower maintenance
costs. UHPC has that potential. As a bridge owner, being our second project, we ve had
a great experience using UHPC. Test results have been great. The material has performed
to this point great, and it s shown great promise for things to come in the future.
Coreslab Structures produced the UHPC waffle slab components at its Omaha precast plant.
They demonstrated that it was possible to use new materials, such as UHPC, to precast
bridge deck components with few alterations to existing technology and processes. UHPC
could change the way bridge decks are constructed and significantly extend the service life
of highway infrastructure as well as open up new markets for precast manufacturers.
The many advantages of UHPC make it a viable choice for many bridge projects. For more
information on the UHPC waffle bridge deck project visit the Highways for LIFE web site.
For more information on UHPC, contact the structural concrete research program at FHWA's
Turner-Fairbank Highway Research Center.