Details:

Creators:
Diaz, G Acosta ; Hamilton, H. R.
Diaz, G Acosta ; Hamilton, H. R. Less -
Corporate Creators:
University of Florida. Dept. of Civil and Coastal Engineering
Corporate Contributors:
Florida. Department of Transportation
Subject/TRT Terms:
[+]
Cracking End Region Fiber Reinforced Concrete Florida I-Beam Girder Bridges Girders I Beams Prestressed Concrete Prestressed Concrete Bridges Tensile Strength
Resource Type:
Tech Report
Geographical Coverage:
Florida ; United States
Florida ; United States Less -
Edition:
Final Report
Corporate Publisher:
Florida. Department of Transportation
Abstract:
In prestressed bridge girders, end region reinforcement is used to control cracking caused by high tensile stresses that occur due to prestress transfer. Partial strand debonding and additional mild steel reinforcement are commonly used to control end region cracking. In some cases, these measures do not effectively control cracking, resulting in construction delays, potential repairs, additional costs, and potential compromise of long-term durability. Fiber-reinforced concrete (FRC) provides a possible solution to end region cracking. Since end region cracking is a serviceability state, not an ultimate strength state, crack control using fibers may provide better results than conventional end region detailing. To evaluate the effectiveness of FRC, experimental and analytical work were conducted. The experimental program covered the evaluation of the effectiveness of steel and macrosynthetic fibers to control end region cracking. Five precast prestressed Florida I-beams were constructed using fiber volume ratios of 0.3%, 0.5%, and 0.7%. Hooked-end steel fibers at a volume of 0.3% and 0.7%, crimped steel fibers at volume of 0.7% and macrosynthetic fiber at a volume of 0.5% were used in the investigation. Concrete and mild steel reinforcement strain were collected during prestressed transfer, and end region cracks were monitored immediately following prestress transfer and for a period of 148 days. The experimental results indicated that the use of FRC can reduce end region crack widths. In addition, the use of steel fibers at a volume fraction of 0.7% combined with reduced end region reinforcement was more effective than the FDOT typical end region reinforcement at maintaining crack widths smaller than 0.006 in. A comparison of crack repair that would be required for the test specimens is presented to provide a practical comparison of FRC performance in this testing. The analytical program was conducted in two phases. The first phase consisted of calibrating a material model that represents the post-cracking behavior of FRC. The second phase consisted of modeling of the FIB-78 girders during prestress transfer. The results from the experimental program were used to validate the analytical model. Good agreement was found between the experimental and analytical results of end region cracking immediately following prestress transfer. The results from the analytical work confirm that FRC can effectively be used to reduce end region cracks.
Format:
PDF
Funding:
BDV31-977-41
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:8f0cdbe7cfd327658eedeb9460792385cc307a0d08c3a1e59ee6ce9082b0c7d3
Download URL:
https://rosap.ntl.bts.gov/view/dot/53970/dot_53970_DS1.pdf
File Type:

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