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Year:
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2008
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VTRC No.:
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09-R5
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Abstract:
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This study evaluated the bulb-T beams made with self-consolidating concrete (SCC) used in the Route 33 Bridge over the Pamunkey River at West Point, Virginia. Before the construction of the bridge, two test beams with SCC similar in cross section to the actual beams in the structure were cast and loaded to failure at the Federal Highway Administration's Turner-Fairbank Highway Research Center in McLean, Virginia. They were tested for transfer length, development length, flexural strength, and shear strength. These test beams demonstrated that SCC members can be designed using the same methods, assumptions, and limiting values as used for normally consolidated concrete beams. Based on the positive results, beams with SCC were cast and placed in the Route 33 Bridge. The study found that SCC yielding adequate slump flow can be prepared without segregation and with satisfactory strength and acceptably low permeability. However, proper attention must be devoted to mixture proportioning, workability, stability, and air content to ensure the quality of the product. The use of SCC in beams will have two major benefits: (1) expedited construction at the plant, a savings that is difficult to estimate at this time, and (2) improved quality. If the second benefit provides a 10 percent increase in service life, which is a reasonable expectation; given a typical $10.68 million yearly expenditure for prestressed concrete beams, this could lead to a cost savings for the Virginia Department of Transportation of close to $1 million per year.
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