Flexural Response of Continuous Concrete Beams Prestressed with External Tendons
Publication: Journal of Bridge Engineering
Volume 18, Issue 6
Abstract
This article presents the results of a numerical investigation of the flexural behavior of continuous externally prestressed concrete beams. Aspects of behavior studied include the increase in stress in external tendons, moment redistribution in the postelastic range, and secondary moments as a result of prestressing. A finite-element model for the full-range analysis of continuous externally prestressed concrete beams is introduced. The model predictions agree well with the experimental results. The analysis shows that the ultimate stress increase in external tendons of continuous beams is dependent on both the number and rotation of plastic hinges that can be developed at failure load. The degree of moment redistribution is significantly influenced by the nonprestressed tension steel and the pattern of loading. An approach based on the linear transformation concept is designed to examine the secondary moments over the entire loading up to the ultimate. The results indicate that the secondary moments increase linearly with the prestressing force and can be conveniently calculated by an elastic analysis.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The work presented in this article has been supported by the Portuguese Foundation for Science and Technology under Grant No. SFRH/BPD/66453/2009.
References
American Concrete Institute (ACI). (1971). Building code requirements for structural concrete (ACI 318-71) and commentary (ACI 318R-71), ACI, Farmington Hills, MI.
American Concrete Institute (ACI). (2011). Building code requirements for structural concrete (ACI 318-11) and commentary (ACI 318R-11), ACI, Farmington Hills, MI.
Aravinthan, T., Witchukreangkrai, E., and Mutsuyoshi, H. (2005). “Flexural behavior of two-span continuous prestressed concrete girders with highly eccentric external tendons.” ACI Struct. J., 102(3), 402–411.
Ariyawardena, N., and Ghali, A. (2002). “Prestressing with unbonded internal or external tendons: Analysis and computer model.” J. Struct. Eng., 128(12), 1493–1501.
Au, F. T. K., Su, R. K. L., Tso, K., and Chan, K. H. E. (2008). “Behaviour of partially prestressed beams with external tendons.” Mag. Concrete Res., 60(6), 455–467.
Dall’Asta, A., Ragni, L., and Zona, A. (2007). “Simplified method for failure analysis of concrete beams prestressed with external tendons.” J. Struct. Eng., 133(1), 121–131.
European Committee of Standardization (CEN). (2002). “Eurocode: Basis of structural design.” EN 1990-2002, Brussels, Belgium.
Ghallab, A., and Beeby, A. W. (2005). “Factors affecting the external prestressing stress in externally strengthened prestressed concrete beams.” Cem. Concr. Compos., 27(9-10), 945–957.
Harajli, M., Khairallah, N., and Nassif, H. (1999). “Externally prestressed members: Evaluation of second-order effects.” J. Struct. Eng., 125(10), 1151–1161.
Harajli, M. H., Mabsout, M. E., and Al-Hajj, J. A. (2002). “Response of externally post-tensioned continuous members.” ACI Struct. J., 99(5), 671–680.
He, Z. Q., and Liu, Z. (2010). “Stresses in external and internal unbonded tendons: Unified methodology and design equations.” J. Struct. Eng., 136(9), 1055–1065.
Hognestad, E. (1951). “A study of combined bending and axial load in reinforced concrete members.” Bulletin No. 399, Engineering Experiment Station, Univ. of Illinois, Urbana, IL.
Kwak, H. G., and Kim, S. P. (2002). “Nonlinear analysis of RC beams based on moment–curvature relation.” Comput. Struct., 80(7–8), 615–628.
Lin, T. Y., and Burns, N. H. (1981). Design of prestressed concrete structures, 3rd Ed., Wiley, New York.
Lopes, S. M. R., Harrop, J., and Gamble, A. E. (1997). “Study of moment redistribution in prestressed concrete beams.” J. Struct. Eng., 123(5), 561–566.
Lou, T. J., Lopes, A. V., and Lopes, S. M. R. (2012). “Influence of span-depth ratio on behavior of externally prestressed concrete beams.” ACI Struct. J., 109(5), 687–696.
Lou, T. J., and Xiang, Y. Q. (2006). “Finite element modeling of concrete beams prestressed with external tendons.” Eng. Struct., 28(14), 1919–1926.
Lou, T. J., and Xiang, Y. Q. (2010). “Numerical analysis of second-order effects of externally prestressed concrete beams.” Struct. Eng. Mech., 35(5), 631–643.
MacGregor, R. J. G. (1989). “Strength and ductility of externally post-tensioned segmental box girders.” Ph.D. thesis, Univ. of Texas, Austin, TX.
Menegotto, M., and Pinto, P. E. (1973). “Method of analysis for cyclically loaded reinforced concrete plane frames.” Proc., IABSE Symp. on Resistance and Ultimate Deformability of Structures Acted on Well-Defined Repeated Loads, Lisbon, Int. Association for Bridge and Structural Engineering, Portugal, 15–22.
Ng, C. K., and Tan, K. H. (2006). “Flexural behaviour of externally prestressed beams. Part II: Experimental investigation.” Eng. Struct., 28(4), 622–633.
Pisani, M. A. (2005). “Geometrical nonlinearity and length of external tendons.” J. Bridge Eng., 10(3), 302–311.
Pisani, M. A. (2009). “Numerical analysis of continuous beams prestressed with external tendons.” J. Bridge Eng., 14(2), 93–101.
Ramos, G., and Aparicio, A. C. (1996). “Ultimate analysis of monolithic and segmental externally prestressed concrete bridges.” J. Bridge Eng., 1(1), 10–17.
Roberts-Wollmann, C. L., Kreger, M. E., Rogowsky, D. M., and Breen, J. E. (2005). “Stresses in external tendons at ultimate.” ACI Struct. J., 102(2), 206–213.
Scott, B. D., Park, R., and Priestley, M. J. N. (1982). “Stress-strain behavior of concrete confined by overlapping hoops at low and high strain rates.” ACI Struct. J., 79(1), 13–27.
Tan, K. H., and Ng, C. K. (1997). “Effects of deviators and tendon configuration on behavior of externally prestressed beams.” ACI Struct. J., 94(1), 13–22.
Tan, K. H., and Tjandra, R. A. (2003). “Shear deficiency in reinforced concrete continuous beams strengthened with external tendons.” ACI Struct. J., 100(5), 565–572.
Tan, K. H., and Tjandra, R. A. (2007). “Strengthening of RC continuous beams by external prestressing.” J. Struct. Eng., 133(2), 195–204.
Information & Authors
Information
Published In
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Sep 28, 2011
Accepted: Feb 29, 2012
Published online: Mar 3, 2012
Published in print: Jun 1, 2013
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.