Nonlinear Features of the Bond-Slip Ascending Branch
Publication: Journal of Materials in Civil Engineering
Volume 32, Issue 10
Abstract
The bond between a deformed rebar and concrete is determined in pullout tests, using cylindrical concrete specimens with centrally embedded rebars, having a predetermined number of bonded ribs. In these experiments, the external measured parameters are the applied pullout load at the rebar end and the slip. This setup does not allow examination of the evolution of local damage in the concrete near the ribs, and the experimental research yields only the average bond stress versus slip relationship, which characterizes the bond property. The bond-slip curve is composed of an ascending branch along a short slip range and a following descending branch along the major slip range. Commonly, the different studies focus on the descending branch, although the maximum bond resistance is gradually developed along the ascending branch. The present study investigates in detail the ascending branch, which is commonly described by a smooth monotonic curve. There are no experimental data in the literature on the evolution of the resistance to pullout loading and the accompanying damage along the ascending branch. This study investigates the different stages of bond resistance development up to the maximum bond stress, and examines the local damage growth and its effect on the bond-slip curve smoothness. This investigation identifies that the ascending curve is not a smooth curve at all and it is composed of several segments with localized gradient changes. A complementary experimental study using an innovative experimental setup allows monitoring the local damage and strain fields in the concrete near the ribs during this part of the experiment. These tests provide new insight and complement the present study findings that the local gradient changes along the ascending curve result from the gradual formation and extension of interior damage with an accumulating effect during loading.
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Data Availability Statement
No data, models, or code were generated or used during the study.
Acknowledgments
This work is partly supported by the Israeli Ministry of Science, Technology and Space. The research grant is greatly appreciated. We would like to also thank E. Itzhak and E. Gershengorn for their valuable technical support.
References
Cowell, A. D., E. P. Popov, and V. V. Bertero. 1982. Effect of concrete types and loading conditions on local bond-slip relationships. Berkeley, CA: Earthquake Engineering Research Centre, Univ. of California, Berkeley.
Eligehausen, R., E. P. Popov, and V. V. Bertero. 1983. Local bond stress-slip relationships of deformed bars under generalized excitations. Berkeley, CA: Earthquake Engineering Research Centre, Univ. of California, Berkeley.
fib (Fédération Internationale du Béton). 2013. Lausanne, Switzerland: fib.
Leibovich, O., D. Z. Yankelevsky, and A. N. Dancygier. 2016. “An innovative experimental procedure to study local rebar-concrete bond by direct observations and measurements.” Exp. Mech. 56 (5): 673–682. https://doi.org/10.1007/s11340-015-0116-z.
Leibovich, O., D. Z. Yankelevsky, and A. N. Dancygier. 2018. “Direct digital image analysis of local displacements and strains in pull-out test.” Structures 14 (Jun): 230–242. https://doi.org/10.1016/j.istruc.2018.03.014.
Leibovich, O., D. Z. Yankelevsky, and A. N. Dancygier. 2019a. “Circumferential strains on a concrete specimen in a pullout test.” Struct. Concr. 20 (3): 986–995. https://doi.org/10.1002/suco.201800172.
Leibovich, O., D. Z. Yankelevsky, and A. N. Dancygier. 2019b. “Role of internal damage mechanisms in controlling bond-slip behavior in pullout tests in concrete.” J. Mater. Civ. Eng. 31 (12): 04019284. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002912.
RILEM. 1970. “Bond test for reinforcing steel: 2. Pullout test.” Mater. Struct. 3 (15): 175–178.
Soroushian, P., K. B. Choi, G. H. Park, and F. Aslani. 1991. “Bond of deform-bars to concrete: Effects of confinement and strength of concrete.” ACI Mater. J. 88 (3): 227–232.
Viwathanatepa, S., E. P. Popov, and V. V. Bertero. 1979. Effect of generalized loading on bond of reinforcing bar embedded in confined concrete. Berkeley, CA: Earthquake Engineering Research Centre, Univ. of California, Berkeley.
Information & Authors
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Published In
Journal of Materials in Civil Engineering
Volume 32 • Issue 10 • October 2020
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Nov 11, 2019
Accepted: Mar 17, 2020
Published online: Jul 21, 2020
Published in print: Oct 1, 2020
Discussion open until: Dec 21, 2020
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