Cracking and Tension Stiffening Behavior of High-Strength Concrete Tension Members Subjected to Axial Load

Abstract

This paper presents the test results of 35 direct tensile specimens to investigate the effect of concrete strength on the tension stiffening effect and cracking response in axially loaded reinforced concrete tensile members. Three concrete strengths 25, 60 and 80 MPa were included as a major experimental parameter together with six concrete cover thickness ratios. The results showed that as higher strength concrete was employed, not only splitting cracks along the reinforcement more extensive, but also the transverse crack spacing became smaller. Thereby, the effective tensile stiffness of the high-strength concrete specimens at the stabilized cracking stage was much smaller than those of normal-strength concrete specimens. This observation is contrary to the current design provisions, and the reduction in the tension stiffening effect by employment of high-strength concrete is much greater than that would be expected. Based on the present results, a modification factor is proposed to account for the effect of the cover thickness and the concrete strength.

Keywords

bond cover thickness crack spacing high-strength concrete tension stiffening effect

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References

Abrishami

H.H.

and Mitchell

(1996). “Influence of splitting cracks on tension stiffening”, ACI Structural Journal, Vol. 93, No. 6, pp.703–710.

ACI Committee 224. (2005). ACI Manual of Concrete Practice – Part 2: Control of Cracking in Concrete Structures, American Concrete Institute, Detroit, USA.

Azizinamini

Stark

Roller

J.J.

and Ghosh

S.K.

(1993). “Bond performance of reinforcing bars embeded in high-strength concrete”, ACI Structural Journal, Vol. 90, No. 5, pp. 554–561.

Broms

B.B.

(1965). “Stress distribution in reinforced concrete member with tension cracks”, ACI Journal, Vol. 62, No. 9, pp. 1095–1108.

Broms

B.B.

(1965). “Crack width and crack spacing in reinforced concrete members”, ACI Journal, Vol. 62, No. 9, pp. 1237–1256.

CEB-FIP. (1991). CEB-FIP Model Code 1990, Comite Euro-International Du Beton, Paris, France.

FIB(CEB-FIP). (1999). Structural Concrete: Textbook on Behavior, Design and Performance – Volume 1, International Federation for Structural Concrete, Lausanne, Switzerland.

Hungspreug

(1981). Local Bond Between a Reinforced Bar and Concrete under High Intensity Cyclic Load, Structural Engineering Report No. 81–6, Cornell University, Ithaca, NY, USA.

Leonhardt

(1977). Crack Control in Concrete Structures, IABSE Surveys No. S-4/77, IABSE Periodical 3/1977, International Association for Bridge and Structural Engineering, Zurich, Switzerland.

10.

Stroband

(1991). Experimental Research into the Bond Behavior of Reinforcing Bars in Light weight and Normal Weight Concrete, Report 25.5-91-3/VF C, Delft University of Technology, Netherlands.