As sustainability and concerns about the long term
durability of America's infrastructure continue to
make headlines, government entities are partnering
with private businesses to develop innovative solutions
to address these challenges. Coreslab Structures
(OMAHA) Inc. is no stranger to innovation and
has participated in several research projects.
Whether it's finding ways to build more resource efficient
bridges, increasing load carrying capacities of
components, or dramatically extending the functional
service life of structures through the use of innovative
materials; Coreslab is helping to make a difference.
Coreslab has recently been awarded a grant from the
Federal Highway Administration's (FHWA) Highways
for LIFE program to manufacture and perform testing
of full-depth waffle deck panels made of ultra high performance
concrete (UHPC). According to the
FHWA, the purpose of the Highways for LIFE program
is to accelerate the adoption of innovations and new
technologies, thereby improving safety and highway
quality while reducing congestion caused by construction.
"There are two key phases of this research project,"
stated Todd Culp, PE who serves as Vice President/
General Manager of Coreslab Structures (OMAHA)
Inc., "Phase I activities will focus on the manufacturing,
testing, and validation of specimen panels and
the second phase includes an actual demonstration
bridge project in Wapello County, IA." According to
Culp, the future of this innovation looks promising.
This innovative bridge deck system will be the first
project in the world to combine precast UHPC waffle
deck panels connected by UHPC field-cast joints.
UHPC is an extremely durable material with compressive
strengths ranging from 24,000 to 30,000 psi. This
unique characteristic provides increased resistance
against the effects of weather, chlorides, impact,
abrasion, salt scaling, fatigue and overload. For this
project, a patented UHPC mix called Ductal® was supplied
by Lafarge North America.
The waffle slab design uses shape optimization to reduce
the amount of materials needed while improving
structural performance. The field-cast UHPC joint
fill solution eliminates historical problems associated
with joints in precast bridge deck systems due to its
strength, durability, reduced joint size and elimination
of post-tensioning. By combining the positive attributes
of UHPC with the efficiency of the waffle panel
design, the bridge deck system provides an extremely
durable option that enables longer spans, efficient
use of materials, less weight, and faster construction.
UHPC Full Depth Waffle Deck Panels combined with
UHPC joint fill can be used for new construction as
well as the rehabilitation of existing deteriorated
bridge decks. The use of this solution for existing
bridge rehabilitation not only restores the deck, but
also may provide opportunities for upgrading the load
capacity of existing bridges, through improved
strength and the reduction of deck self weight.
The project is currently in the design validation and
testing phase. "Two 8' x 10' specimen panels have
been produced, steam cured, and shipped to Iowa
State University to undergo fatigue and ultimate loading
tests," stated John Heimann, Project Manager
with Coreslab Structures (OMAHA) Inc., "The panel to
panel joints will be tested during this time as well.
These test results will be reviewed by FHWA before
moving forward with Phase II of the project."
The laboratory testing and bridge demonstration project
will provide excellent opportunities to assess the
structural performance, deck constructability, fieldcast
joint performance, and overall behavior of the
bridge deck panels. In addition, Coreslab Structures
(OMAHA) Inc. will produce a life cycle cost analysis
that addresses the viability of production, deployment
and operation of the bridge deck panels.
From initial consultation to engineering, from plant production to jobsite erection, and finally
project closeout and certification, we at Coreslab Structures will continue to provide dependability
and quality service.
Coreslab Structures (OMAHA) Inc.
George Schuler, LEED AP
Project Consultant
(402) 291-0733 ext. 466
gschuler@coreslab.com
