Identification of Stress-Slip Law for Bar or Fiber Pullout by Size Effect Tests
Publication: Journal of Engineering Mechanics
Volume 121, Issue 5
Abstract
Test results on the size effect in the pullout strength of reinforcing bars embedded in concrete are presented. Attention is focused on failures due solely to interface slip, with no cracking in the surrounding concrete. This type of failure is achieved by using smooth round bars and a sufficiently large ratio of bar diameter to embedment length. Elimination of cracking in the surrounding concrete makes it possible to study the characteristics of the interfacial shear fracture between steel and concrete. The results of tests of geometrically similar specimens show that interfacial shear fracture causes a size effect on the nominal strength in pullout. The size effect is found to be transitional between plastic failure (the current approach of concrete design codes, for which there is no size effect) and linear elastic fracture mechanics (for which the size effect is the maximum possible). This transitional size effect can be approximately described by the size effect law proposed by Bažant in 1984 for quasibrittle failures in general. By fitting a theoretical formula obtained in a previous study (by Bažant and Desmorat in 1994) to the size effect data, the basic characteristics of the stress-slip law for interface fracture are determined. These include the interfacial fracture energy, the shear bond strength (debonding shear stress), and the residual frictional shear stress. The same method could be used for identifying the interfacial fracture characteristics of other materials, e.g., fibers in cementitious composites.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Alwan, J. M., Naaman, A. E., and Hansen, W.(1991). “Pull-out work of steel fibers from cementitious composites: analytical investigation.”Cement and Concrete Composites, 13(4), 247–255.
2.
Bažant, Z. P.(1984). “Size effect in blunt fracture: concrete, rock, metal.”J. Engrg. Mech., ASCE, 110(4), 518–535.
3.
Bažant, Z. P., and Sener, S. (1988). “Size effect in pullout tests.”ACI Mat. J., Vol. 85, 347–351.
4.
Bažant, Z. P., Xi, Y., and Reid, S. G.(1991a). “Statistical size effect in quasi-brittle structures. I: Is Weibull theory applicable?”J. Engrg. Mech., ASCE, 117(11), 2609–2622.
5.
Bažant, Z. P., and Xi, Y.(1991). “Statistical size effect in quasi-brittle structures. II. Nonlocal theory.”J. Engrg. Mech., ASCE, 117(11), 2623–2640.
6.
Bažant, Z. P., and Cedolin, L. (1991). Stability of structures: elastic, inelastic, fracture and damage theories . Oxford University Press, New York, N.Y.
7.
Bažant, Z. P., and Desmorat, R.(1994). “Size effect in fiber or bar pullout with interface fracture and softening slip.”J. Engrg. Mech., ASCE, 120(9), 1945–1962.
8.
“Building code requirements for reinforced concrete.” (1983). Am. Concrete Inst. (ACI) Committee 318, Detroit, Mich.
9.
Dörr, K. (1978). “Bond-behaviour of ribbed reinforcements under transversal pressure.”Proc., Symp. on Nonlinear Behaviour of R. C. Spatial Structures, Int. Association for Shell and Spatial Struct., Darmstadt, Germany, 13–24.
10.
Edwards, A. D., and Yannopoulos, P. J.(1979). “Local bond-stress to slip relationship for hot rolled deformed bars and mild steel plain bars.”ACI J., 76(3), 405–420.
11.
Gao, Y.-C., Mai, Y.-W., and Cotterell, B. (1988). “Fracture of fiber-reinforced materials.”J. Appl. Mathematics and Phys., Vol. 39, 550–572.
12.
Giuriani, E., Plizzari, G., and Schumm, C.(1991). “Role of stirrups and residual tensile strength of cracked concrete on bond.”J. Struct. Engrg., ASCE, 117(1), 1–18.
13.
Guerney, C., and Hunt, J. (1967). “Quasi-static crack propagation.”Proc., Royal Soc. of London, London, England, Ser. A, Vol. 229, 508–524.
14.
Hsueh, C.-H. (1990a). “Interfacial debonding and fiber pullout stresses of fiber reinforced composites, II: nonconstant interfacial bond strength.”Mat. Sci. and Engrg., A125(5), 67–73.
15.
Hsueh, C.-H. (1990b). “Interfacial debonding and fiber pullout stresses of fiber reinforced composites.”Mat. Sci. and Engrg., Vol. A123, 1–11.
16.
Hsueh, C.-H. (1991a). “Interfacial debonding and fiber pullout stresses of fiber reinforced composites, III: with residual radial and axial stresses.”Mat. Sci. and Engrg., Vol. A145, 135–142.
17.
Hsueh, C.-H. (1991b). “Interfacial debonding and fiber pullout stresses of fiber reinforced composites, IV: sliding due to residual stresses.”Mat. Sci. and Engrg., Vol. A145, 143–150.
18.
Hutchinson, J. W., and Jensen, H. M. (1990). “Models of fiber debonding and pullout in brittle composites with friction.”Mech. of Mat., Vol. 9, 139–163.
19.
Lahnert, B. J., Houde, J., and Gerstle, K. H.(1984). “Direct measurement of slip between steel and concrete.”ACI J., 83(86), 974–982.
20.
Lawrence, P. J. (1972). “Some theoretical considerations of fiber pull-out from an elastic matrix.”J. Mat. Sci., Vol. 7, 1–7.
21.
Naaman, A. E.(1991a). “Fiber pullout and bond slip. I: Analytical study.”J. Struct. Engrg., ASCE, 117(9), 2769–2790.
22.
Naaman, A. E.(1991b). “Fiber pullout and bond slip. II: Experimental validation.”J. Struct. Engrg., ASCE, 117(9), 2791–2800.
23.
Naaman, A. E., and Najm, H. S.(1991). “Bond-slip mechanism of steel fibers in concrete.”ACI Mat. J., 88(2), 135–144.
24.
Nilson, A. H.(1972). “Internal measurement of bond slip.”Am. Concrete Inst. J., 69(7), 439–441.
25.
Orangun, C. O., Jirsa, J. O., and Breen, J. E. (1977). “A reevaluation of test data on development length and splices.”ACI J., (Mar.), 114–122.
26.
Outwater, J. P., and Murphy, M. C. (1969). “On the fracture energy of unidirectional laminate.”Proc., 24th Annu. Tech. Conf. of Reinforced Plastics/Composite Div.; Paper No. 11c, Soc. of the Plastics Industry, Inc., New York.
27.
Pijaudier-Cabot, G., Mazars, J., and Pulikowski, J.(1991). “Steel-concrete bond analysis with nonlocal continuous damage.”J. Struct. Engrg., ASCE, 117(3), 862–882.
28.
RILEM Committee TC 89-FMT. (1990). “Size effect method for determining fracture energy and process zone of concrete.”Mat. and Struct., Paris, France, Vol. 23, 461–465.
29.
Rots, J. G. (1985). “Bond slip simulation using smeared cracks and/or interface element.”Res. Rep. 85.01., Dept. of Struct. Mech., Delft Univ. of Technol., Delft, The Netherlands.
30.
Stang, H., and Shah, S. P. (1986). “Failure of fiber-reinforced conposites by pullout fracture.”J. Mat. Sci., Vol. 21, 953–957.
31.
Takaku, A., and Arridge, R. G. C. (1973). “The effect of interfacial radial and shear stress on fiber pullout in composite materials.”J. of Phys.-D. Vol. 6, 2038–2047.
32.
Yue, C. Y., and Cheung, W. L. (1992a). “Interfacial properties of fibrous composites: model for the debonding and pullout process.”J. Mat. Sci., Vol. 27, 3173–3180.
33.
Yue, C. Y., and Cheung, W. L. (1992b). “Interfacial properties of fibrous composites. Determination of interfacial shear strength, interfacial coefficient of friction and the shrinkage of the fiber.”J. Mat. Sci., Vol. 27, 3181–3191.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 121 • Issue 5 • May 1995
Pages: 620 - 625
Copyright
Copyright © 1995 American Society of Civil Engineers.
History
Published online: May 1, 1995
Published in print: May 1995
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.