Detailing for Reinforcement Stability in RC Members
Publication: Journal of Structural Engineering
Volume 124, Issue 6
Abstract
Instability of reinforcement in adequately detailed reinforced concrete (RC) structural elements is a symptom of excessive deformation in compression, and it typically marks the limit of usable ductility of the member. Because the supply of ductility (deformability) is a measure of the effectiveness of the confining reinforcement, detailing necessary for reinforcement stability is intimately related to that required for confinement. Existing design models consider the two problems independently, and associate the initiation of bar buckling with the occurrence of a critical milestone of material behavior under compression. The resulting requirements for lateral support of the reinforcement do not correlate well with those obtained from studies for confinement and rarely control in cases of earthquake design. The objective of this paper is to develop alternative requirements for reinforcement stability that recognize the interaction between displacement ductility demand in the critical section, tie effectiveness, limiting concrete strain, bar size, and tie spacing. To quantify this relationship an extensive database consisting of over 300 column tests was compiled from international literature. Tests considered in the database were conducted under repeated axial and flexural load reversals, simulating earthquake effects on specimens with a variety of confining and longitudinal steel arrangements. The database was systematically analyzed to identify from experimental evidence the critical condition for reinforcement stability and its relationship to the limiting average compressive strain and/or ductility demand in the plastic hinge zone, and to the confinement geometry and effectiveness. Recognizing the interdependence between critical buckling conditions and confinement presents an opportunity to relate detailing requirements for the stability of reinforcement to detailing for ductility, and to distinguish between designs intended to satisfy different levels of deformation demand required for construction in various zones of seismic risk.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Azizinamini, A., Baum-Kuska, S., Brungardt, P., and Hatfield, E.(1994). “Seismic behavior of square high-strength concrete columns.”ACI Struct. J., 91(3), 336–345.
2.
Bleich, F. (1952). Buckling strength of metal structures. McGraw-Hill Inc., New York, N.Y.
3.
Bresler, B., and Gilbert, P. H.(1961). “Tie requirements for reinforced concrete columns.”ACI J., 58(26), 555–570.
4.
“Building code requirements for reinforced concrete (ACI318-89) and commentary.” (1989). ACI318R-89, American Concrete Inst., Farmington Hills, Mich.
5.
Cusson, D., and Paultre, P.(1994). “High-strength concrete columns confined by rectangular ties.”J. Struct. Engrg., ASCE, 120(3), 783–804.
6.
Cusson, D., and Paultre, P.(1995). “Stress-strain model for confined high-strength concrete.”J. Struct. Engrg., ASCE, 121(3), 468–477.
7.
French, C. W., and Schultz, A. E. (1991). “Minimum available deformation capacity of reinforced concrete beams.”Earthquake resistant structures—inelastic response and design, ACI SP 127-9, S. K. Ghosh, ed., American Concrete Inst., Farmington Hills, Mich., 363–419.
8.
Imran, I., and Pantazopoulou, S. J.(1996). “Experimental study of plain concrete under triaxial stress.”ACI Mater. J., 93(6), 589–601.
9.
Mander, J. B., Priestley, M. J. N., and Park, R.(1988a). “Observed stress-strain behavior of confined concrete.”J. Struct. Engrg., ASCE, 114(8), 1827–1849.
10.
Mander, J. B., Priestley, M. J. N., and Park, R.(1988b). “Theoretical stress-strain model for confined concrete.”J. Struct. Engrg., ASCE, 114(8), 1804–1826.
11.
Mau, S. T.(1990). “Effect of tie spacing on inelastic buckling of reinforcing bars.”ACI Struct. J., 87(6), 671–677.
12.
Mau, S. T., and El-Mabsout, M.(1989). “Inelastic buckling of reinforcing bars.”J. Struct. Engrg., ASCE, 115(1), 1–17.
13.
Moehle, J. P., and Cavanagh, T.(1985). “Confinement effectiveness of crossties in reinforced concrete.”J. Struct. Engrg., ASCE, 111(10), 2105–2120.
14.
Monti, G., and Nuti, C.(1992). “Nonlinear cyclic behavior of reinforcing bars including buckling.”J. Struct. Engrg., ASCE, 118(12), 3268–3285.
15.
Pantazopoulou, S. J., and Mills, R. H.(1995). “Microstructural aspects of the mechanical behavior of plain concrete.”ACI Mat. J., 92(6), 605–616.
16.
Papia, M., and Russo, G.(1988). “Instability of longitudinal bars in RC columns.”J. Struct. Engrg., ASCE, 114(2), 445–461.
17.
Pfister, J. (1964). “Influence of ties on the behavior of reinforced concrete columns.”ACI J., May, 521–537.
18.
Priestley, M. J. N., and Park, R.(1987). “Strength and ductility of concrete bridge columns under seismic loading.”ACI Struct. J., 84(1), 61–76.
19.
Razvi, S., and Saatcioglu, M.(1994). “Strength and deformability of confined high-strength concrete columns.”ACI Struct. J., 91(6), 678–687.
20.
Razvi, S., and Saatcioglu, M. (1995). “Confinement model for normal strength and high strength concrete columns.”Res. Rep., Ottawa-Carleton Earthquake Engrg. Res. Ctr., Dept. of Civ. Engrg., Univ. of Ottawa, Canada.
21.
Richart, F. E., Brandtzaeg, A., and Brown, R. L. (1928). “A study of the failure of concrete under combined compressive stresses.”Engrg. Experiment. Station Bull. No. 185, Univ. of Illinois, Urbana, Ill.
22.
Saatcioglu, M. (1991). “Deformability of reinforced concrete columns.”Earthquake resistant structures—inelastic response and design, ACI SP 127-10, American Concrete Inst., Farmington Hills, Mich., 421–452.
23.
Saatcioglu, M., and Ozcebe, G. (1989). “Response of reinforced concrete columns to simulated seismic loading.”ACI Struct. J., 86(S1), 3–12.
24.
Scott, B. D. (1980). “Stress-strain relationships for confined concrete: rectangular sections.”Res. Rep. No. 80-6, Dept. of Civ. Engrg., Univ. of Canterbury, Christchurch, New Zealand.
25.
Scribner, C. F.(1986). “Reinforcement buckling in reinforced concrete flexural members.”ACI J., 83(85), 966–973.
26.
Sheikh, S. A., and Khoury, S.(1993). “Confined concrete columns with stubs.”ACI Struct. J., 90(4), 414–431.
27.
Sheikh, S. A., Shah, D. V., and Khoury, S.(1994). “Confinement of high strength concrete columns.”ACI Struct. J., 91(1), 100–111.
28.
Sheikh, S. A., and Toklucu, M. T.(1993). “Reinforced concrete columns confined by circular spirals and hoops.”ACI Struct. J., 90(5), 542–553.
29.
Sheikh, S. A., and Uzumeri, S. M.(1980). “Strength and ductility of tied concrete columns.”J. Struct. Div., ASCE, 106(5), 1079–1102.
30.
Sheikh, S. A., and Uzumeri, S. M.(1982). “Analytical model for concrete confinement in tied columns.”J. Struct. Div., ASCE, 108(12), 2703–2722.
31.
Sheikh, S. A., Yeh, C. C., and Khoury, S.(1990). “Concrete strength in tied columns.”ACI Struct. J., 87(4), 379–385.
32.
Thomsen, J. H., and Wallace, J. W.(1994). “Lateral load behavior of reinforced concrete columns constructed using high-strength materials.”ACI Struct. J., 91(5), 605–615.
33.
Watson, S., Zahn, F. A., and Park, R.(1992). “Confining reinforcement for concrete columns.”J. Struct. Engrg., ASCE, 120(6), 1798–1824.
34.
Wood, S. L., and Sittipunt, C. (1996). “Cyclic response of reinforced concrete structural walls.”Mete A. Sozen symposium—A tribute from his students, ACI SP-162, J. K. Wight and M. E. Kreger, eds., American Concrete Inst., Farmington Hills, Mich., 399–429.
35.
Zahn, F. A. (1986). “Design of reinforced concrete bridge columns for strength and ductility.”Res. Rep. No. 86-7, Dept. of Civ. Engrg., Univ. of Canterbury, Christchurch, New Zealand.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 124 • Issue 6 • June 1998
Pages: 623 - 632
Copyright
Copyright © 1998 American Society of Civil Engineers.
History
Published online: Jun 1, 1998
Published in print: Jun 1998
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.