Size Effect on Failure of Bond Splices of Steel Bars in Concrete Beams
Publication: Journal of Structural Engineering
Volume 125, Issue 6
Abstract
The results of reduced-scale failure tests of simply supported four-point-bend beams of different sizes, containing lapped bond splices of smooth (undeformed) longitudinal reinforcing bars, are reported. The tests consist of two groups, with splices located either in the midspan region with a uniform bending moment, or in one of the end regions with a uniform shear force. The specimens were made of microconcrete with a maximum aggregate size 4.76 mm. Beams of three different heights (50, 100, and 200 mm) were tested. The beams were geometrically similar in three dimensions, and even the bar diameters and cover thicknesses were scaled in proportion. The reinforcement ratio was 0.31%. The results reveal the existence of a significant size effect, which can be approximately described by the size effect law previously proposed by Baant. The size effect is found to be stronger for splices without any spiral than for splices confined by a spiral, and stronger for splices in the maximum shear force region of a beam than for splices in the maximum bending moment region. Generalization of the existing formula of Orangun et al. is proposed and recommended for design. Although the formula provides a safer alternative to the existing approach, further testing is needed for better calibration. The size effect on the nominal bond strength implied by the development length provisions of the current and previous American Concrete Institute code is discussed and shown to be inadequate.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Baant, Z. P. (1984). “Size effect in blunt fracture: Concrete, rock, metal.”J. Engrg. Mech., ASCE, 110(4), 518–535.
2.
Baant, Z. P. ( 1987). “Fracture energy of heterogeneous material and similitude.” SEM-RILEM Int. Conf. on Fracture of Concrete and Rock, S. P. Shah and S. E. Swartz, eds., Society for Experimental Mechanics, 390–402.
3.
Baant, Z. P. ( 1990). “Size effect method for determining fracture energy and process zone of concrete.” Mat. and Struct., 23, 461–465.
4.
Baant, Z. P. ( 1995). “Scaling theories for quasibrittle fracture: Recent advances and new directions.” Fracture mechanics of concrete structures, F. H. Wittmann, ed., Aedificatio, Freiburg, Germany, 515–534.
5.
Baant, Z. P., and Desmorat, R. (1994). “Size effect in fiber or bar pullout with interface softening slip.”J. Engrg. Mech., ASCE, 120(9), 1945–1962.
6.
Baant, Z. P., Li, Z., and Thoma, M. (1995). “Identification of stress-slip law for bar or fiber pullout by size effect tests.”J. Engrg. Mech., ASCE, 121(5), 620–625.
7.
Baant, Z. P., Obolt, J., and Eligehausen, R. (1994). “Fracture size effect: Review of evidence for concrete structures.”J. Struct. Engrg., ASCE, 120, 2377–2398.
8.
Baant, Z. P., and Planas, J. ( 1998). Fracture and size effect in concrete and other quasibrittle materials . CRC Press, Boca Raton, Fla.
9.
Baant, Z. P., and Şener, S. ( 1988). “Size effect in pullout tests.” ACI Mat. J., 85, 347–351.
10.
“Building code requirements for reinforced concrete.” (1992). ACI 318R-89. American Concrete Institute, Detroit.
11.
“Building code requirements for reinforced concrete.” (1995). ACI 318-95. American Concrete Institute, Detroit.
12.
“Fracture mechanics of concrete: Concepts, models and determination of material properties.” (1992). Fracture mechanics of concrete structures, Z. P. Baant, ed., Elsevier Applied Science, London, 1–140.
13.
Orangun, C. O., Jirsa, J. O., and Breen, J. E. ( 1977). “A reevaluation of test data on development length and splices.” ACI J., 74(3), 114–122.
14.
Şener, S. ( 1992). “Size effect in bond splices tests.” FIP '92 Symp., G. Tassi, ed., Hungarian Scientific Society of Building, Budapest, 357–362.
15.
Şener, S. ( 1993). “Size effect in the direct loading tests.” Advances in civil engineering. Proc., 1st Tech. Congr., Middle East Technical University, Ankara, Turkey, 720–727.
16.
Şener, S. ( 1994). “Failure of steel bars in R. C. beams: Test of size effect.” Bull. of Tech. Univ. of Instanbul, 47, 337–355.
17.
Şener, S., and Timur, I. ( 1993). “Size effect in bond splices test under the indirect loading.” Advances in civil engineering. Proc., 1st Tech. Congr., Middle East Technical University, Ankara, Turkey, 728–735.
18.
Zsutty, T. (1985). “Empirical study of bar development behavior.”J. Struct. Engrg., ASCE, 111(1), 205–219.
Information & Authors
Information
Published In
History
Received: Feb 3, 1998
Published online: Jun 1, 1999
Published in print: Jun 1999
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.