Performance Evaluation of Prestressed Girders with 17.8-mm (0.7-in.) Strands
Publication: Journal of Bridge Engineering
Volume 28, Issue 12
Abstract
There has been a growing interest in using large-diameter strands to alleviate congestion by using fewer strands, reduce the total number of girders by increasing girder spacing, increase the span length, and allow shallower girders. While the 2020 AASHTO LRFD Bridge Design Specifications included 17.8-mm (0.7-in.) strands by reference to AASHTO M203, these larger-diameter strands were not used in bridge construction primarily because AASHTO LRFD was silent about the design aspects of members reinforced with 17.8-mm (0.7-in.) strands. The presented multifaceted, multiyear research involved an extensive parametric design case study, nonlinear finite-element analyses, material characterization, component tests, and full-scale girder experiments. This paper focuses on the full-scale girder tests, which were used to examine development length, detailing requirements, and flexural and shear behavior and strength. Experimentally determined development lengths were found to be shorter than those prescribed by the AASHTO LRFD Specification. Flexural and shear strength could be determined using established procedures. The current minimum required amount of confinement reinforcement was found to be sufficient to confine 17.8-mm (0.7-in.) strands. The extension of bottom flange confinement reinforcement was found to be inadequate for cases with partially debonded 17.8-mm (0.7-in.) strands, but extension of bottom flange confinement reinforcement to 1.5d beyond the end of the girder was adequate for cases with no debonded strands. The minimum bottom flange confinement reinforcement required by the AASHTO LRFD Specification must be extended to at least 1.5d beyond the termination of the longest debonded length of 17.8-mm (0.7-in.) strands.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
The experimental data that support the findings of this study are available from the corresponding author upon request.
Acknowledgments
The research presented in this paper was a part of NCHRP Project 12-109 Strand Debonding for Pretensioned Girders. The authors thank the NCHRP Project Panel and the Senior Program Officer, Dr. Waseem Dekelbab, for their project oversight, valuable insight, and feedback throughout the project.
References
AASHTO. 2020. AASHTO LRFD bridge design specifications. 9th ed. Washington, DC: AASHTO.
Akhnoukh, A. K. 2008. Development of high performance precast/prestressed bridge girders. Lincoln, NE: Univ. of Nebraska.
Akhnoukh, A. K. 2013. “Prestressed concrete girder bridges using large 0.7 inch strands.” J. Civ. Environ. Struct. Constr. Archit. Eng. World Acad. Sci. Eng. Technol. 7 (9): 277–281.
ASTM. 2015a. Standard specification for low-relaxation, seven-wire steel strand for prestressed concrete. ASTM A416-15. West Conshohocken, PA: ASTM.
ASTM. 2015b. Standard test method for evaluating bond of seven-wire steel prestressing strand. ASTM A1081. West Conshohocken, PA: ASTM.
Bentz, E. C. 2000. “Response 2000.” Accessed November 16, 2022. https://response-2000.software.informer.com/1.0/.
Bolduc, M. W., B. M. Shahrooz, K. A. Harries, R. A. Miller, H. G. Russell, and W. A. Potter. 2023. “Experimental background behind new AASHTO requirements for partially debonded strands.” PCI J. 68 (2): 71–87.
Briere, V., K. A. Harries, J. Kasan, and C. Hager. 2013. “Dilation behavior of seven-wire prestressing strand—The Hoyer effect.” Constr. Build. Mater. 40: 650–658. https://doi.org/10.1016/j.conbuildmat.2012.11.064.
Dang, C. N. 2015. Measurement of transfer and development lengths of 0.7 in. Strands on pretensioned concrete elements. Fayetteville, AR: Univ. of Arkansas.
fib (International Federation for Structural Concrete). 2008. Constitutive modelling for high strength/high performance concrete. fib Bulletin 42. State-of-art report. Lausanne, Switzerland: fib.
Hanna, K. E., G. Morcous, and M. K. Tadros. 2010a. Rapid construction of pacific street bridge. Project SPR-PL-1 (037) P587. Lincoln, NE: Nebraska Dept. of Roads.
Hanna, K. A., G. Morcous, and M. K. Tadros. 2010b. Design aids of NU I-girder bridges. Project No. P322 Final Report. Lincoln, NE: Nebraska Dept. of Roads.
IADOT (Iowa Dept. of Transportation). 2011. “Bulb Tee ‘B’ Beam—5′-0″ Span.” Standard Sheet 4752. Accessed November 16, 2022. https://iowagov/bridge/standards/english/EnglishBeams.pdf.
Morcous, G. 2013. Implementation of 0.7 in. diameter strands in prestressed concrete girders. Project SPR-P1(13) M333. Lincoln, NE: Nebraska Dept. of Roads.
Morcous, G., A. Hatami, M. Maguire, K. Hanna, and M. K. Tadros. 2012. “Mechanical and bond properties of 18-mm (0.7-in.-) diameter prestressing strands.” J. Mater. Civ. Eng. 24 (6): 735–744. https://doi.org/10.1061/(ASCE)MT.1943-5533.0000424.
Patzlaff, Q., G. Morcous, K. Hanna, and M. K. Tadros. 2012. “Bottom flange confinement reinforcement in precast prestressed concrete bridge girders.” J. Bridge Eng. 17 (4): 607–616. https://doi.org/10.1061/(ASCE)BE.1943-5592.0000287.
PCI (Precast/Prestressed Concrete Institute). 2011. “PCI bridge design manual.” Appendix B. Accessed November 16, 2022. https://www.pci.org/PCI_Docs/Design_Resources/Transportation_Resources/Box%20Shapes.pdf.
Ramirez, J. A., and B. W. Russell. 2008. Transfer, development, and splice length for strand/reinforcement in high-strength concrete. NCHRP Rep. No. 603. Washington, DC: Transportation Research Board.
Schuler, G. 2009. Producer’s experience with 10,000 psi concrete and 0.7-in. Diameter strands. HPC Bridge Views. Washington, DC: Federal Highway Administration, US Dept. of Transportation. Issue 54, March/April.
Shahrooz, B. M., R. A. Miller, K. A. Harries, and R. Castrodale. 2022. Use of 0.7-in. diameter strands in precast pretensioned girders. NCHRP Rep. No. 994. Washington, DC: Transportation Research Board.
Shahrooz, B. M., R. A. Miller, K. A. Harries, Q. Yu, and H. G. Russell. 2017. Strand debonding in pretensioned girders. NCHRP Rep. No. 849. Washington, DC: Transportation Research Board.
Song, W., Z. J. Ma, J. Vadivelu, and E. G. Burdette. 2014. “Transfer length and splitting force calculation for pretensioned concrete girders with high-capacity strands.” J. Bridge Eng. 19 (7): 04014026-1–04014026-8. https://doi.org/10.1061/(ASCE)BE.1943-5592.0000566.
Tadros, M. K., and G. Morcous. 2011. Impact of 0.7 inch diameter strands on NU I-girders. Project No. P311. Lincoln, NE: Nebraska Dept. of Roads.
Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 28 • Issue 12 • December 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Feb 1, 2023
Accepted: Jul 10, 2023
Published online: Sep 29, 2023
Published in print: Dec 1, 2023
Discussion open until: Feb 29, 2024
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.