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Hawaii Bridge Uses New HPC Deck Mix
The North-South Road Separation structure carrying Interstate Route H-1over the newly constructed North-South Road will help to relieve congestion in one of the fastest growing parts of Oahu, Hawaii. This prestressed concrete spliced-girder bridge was constructed with a high-performance concrete (HPC) deck mix that aimed at reducing creep and shrinkage, while employing a new type of air entrainment technology.
Hawaii is home to aggregates which, when used in concrete, may result in concrete with large values for shrinkage and creep. To reduce this, the design engineer, KSF, Inc., proposed using a new high-performance concrete deck mix developed with Island Ready Mix and Miracon, Inc. The contractor for North-South Road project Phase 1C, Kiewit Pacific Co., and the State of Hawaii Department of Transportation, were accommodating in implementating the new concrete mix that helped limit creep and shrinkage.
Placement of all bridge deck concrete in Hawaii is done at night in order to reduce evaporation. This deck placement was unique because it consisted of more than 1,000 cubic yards of concrete placed with no deck expansion joints. The design strength of the HPC deck was 6000 psi at 28 days, while approximately 8000 psi was achieved at 28 days. Preliminary measurements have indicated a 75% reduction in shrinkage and a 60% reduction in creep. As of this time, no cracks have been found in the deck. More on the North-South Road Separation.
Q: Why Are More State DOTs Using HPC?
The Federal Highway Administration’s (FHWA) survey of state departments of transportation in 2003/2004 ascertained that almost every state agency had tried high- performance concrete (HPC) in their bridges or had incorporated it into their standard specifications. Recently, the FHWA followed up that initial survey with a second survey that asked more detailed questions to try to determine the extent of HPC usage by each agency.
When asked what HPC performance characteristics were being tested for by the states, the top two answers were compressive strength (48 agencies out of 53 reporting) and rapid chloride permeability (34 agencies). Concrete shrinkage was next with 20 respondents. Flowability, alkali-silica reactivity, and freeze-thaw durability were all tightly grouped with 17 agencies testing for these. Six agencies tested for scaling and sulfate resistance. These responses show how important durability is, for this includes permeability, freeze-thaw resistance, alkali-silica resistance, and scaling and sulfate resistances.
For more information on the FHWA Survey, read the article by FHWA’s Louis Triandafilou on the “Updated FHWA HPC Survey”, HPC Bridge Views, Issue 53, Jan/Feb 2009.
Registration Now Open for 2010 Concrete Bridge Conference
The National Concrete Bridge Council has opened registration
for the 2010 Concrete Bridge Conference to be held February 24-26, at
the Hyatt Regency in Phoenix, Ariz.
The theme of this year’s Conference is “Achieving Safe, Smart,
and Sustainable Bridges” and will include many technical sessions,
a tour of local bridges, a reception featuring the presentation of the
2010 Concrete Bridge Awards, and an exhibit area. The conference will
have five focus areas: Sustainable Bridges, Smart Bridges, Non-Destructive
Evaluations of Bridges, Durable Bridge Decks, and Innovative Design and
Construction.
We welcome exhibitors and attendees for the conference. Both can register
for the conference at the NCBC
Web site.
The deadline for Abstracts has been extended until Friday, August 28, and can be submitted at the NCBC Web site.
Submit Your Bridge for the 2010 Concrete Bridge Awards Competition
There’s still time to submit your bridge for the 12th biennial Concrete Bridge Awards Competition, co-sponsored by PCA and Roads & Bridges magazine. Bridges of all types—highway, railway, transit, and pedestrian—in which the basic structural system is concrete are eligible. Entries are encouraged for cast-in-place or precast bridges (or combinations) with short, medium, or long spans. These bridges can be newly constructed, rehabilitated, or widened structures.
Entries are due September 4, 2009. To be eligible, bridges must have been essentially completed between April 2008 and September 2009. Interested owners, consultants, contractors, or suppliers can submit entries online or by downloading an entry form and submitting a hard copy version.
Awards will be presented at the 2010 Concrete Bridge Conference in Phoenix, Ariz., February 24-26. Winners will be announced in Roads & Bridges magazine and by PCA.
For more information contact Sue Lane at PCA at 202-408-9494 or SLane@cement.org
Tennessee Plans 71 Concrete Bridges with Stimulus Funds
Tennessee Department of Transportation (TDOT) will be undertaking 62 bridge projects with their stimulus funds, which will replace, repair, or newly construct 81 bridges. Of those 81 bridges, 71 will be built of concrete. Materials for three other bridge projects have yet to be determined.
More than $123 million has been awarded so far this year for concrete bridge stimulus projects in Tennessee. The construction jobs will include the removal of existing structures for replacement with prestressed and reinforced concrete structures. Estimated completion dates range from November 2009 through October 2011.
TDOT and the Department of Economic and Community Development estimate approximately 24,000 jobs could be created through the ARRA infrastructure funding for Tennessee.
For more information on Tennessee’s stimulus program, visit their Web site.
U.S. Department of Transportation Announces Innovative
Bridge Research Funds Recipients
The Secretary of Transportation announced the recipients of the Innovative Bridge Research and Deployment (IBRD) program funds for 2009 on June 24. More than $5.2 million in grants were given to 14 states for 20 bridges. Fourteen of the bridge projects involve reinforced or prestressed concrete bridge elements, accounting for $3.5 million (67%) of the grants.
A number of states are using precast concrete bridge elements to accelerate bridge construction, including one in a seismic region. Two of the states will examine reinforcing bars in reinforced concrete bridge elements. Other projects include the use of self-consolidating concrete (SCC), a self-curing concrete, and a light-weight epoxy overlay. More on IBRD projects.
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Cement Association
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202.408.9494 • Fax: 202.408.0877
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