Influence of Concrete Strength on Tension Stiffening

Title & Authors
Influence of Concrete Strength on Tension Stiffening
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Abstract
This paper describes the results obtained from 11 direct tension tests to explore the influence of concrete strength on tension stiffening behavior in reinforced concrete axial members. Three different concrete compressive strengths, 250, 650, and 900kgf/$\small{\textrm{cm}^2}$, were included as a main variable, while the ratio of cover thickness-to-rebar diameter was kept constant to be 2.62 to prevent from splitting cracking. As the results, it was appeared that, as higher concrete strength was used, less tension stiffening effect was resulted, and the residual deformation upon unloading was larger. In addition, the spacing between adjacent transverse cracks became smaller with higher concrete strength. The major cause for those results may be attributed to the fact that nonuniform bond stress concentration at both loaded ends and crack sections becomes severer as higher concrete is used, thereby local bond failure becomes more susceptible. From these findings, it would be said the increase in flexural stiffness resulting from using high-strength concrete will be much smaller than that predicted by the conventional knowledge. Finally, a factor accunting for concrete strength was introduced to take account for the effect of HSC on tension stiffening. This proposed equation predicts well the tension stiffening for the effect of HSC on tension stiffening. This proposed equation predicts well the tension stiffening behavior of these tests.
Keywords
axial tension;bond stress;cracks;high-strength concrete;reinforced concrete;stiffness;tension stiffening effect;
Language
English
Cited by
1.
고장도 콘크리트의 부착특성에 관한 연구,이준구;문인;염환석;김우;

한국콘크리트학회논문집, 2001. vol.13. 5, pp.499-506
References
1.
(Third Editon)CEB., 1978.

2.
ACI Manual of Concrete Practice, 1994. pp.224

3.
ACI Structural Journal, 1996. pp.703-710

4.
ASCE, 1990. vol.116. 3, pp.769-790

5.
ACI Journal, 1986. pp.21-28

6.
ACI Journal, 1971. pp.244-251

7.
ACI Journal, 1981. vol.78. 3, pp.171-178

8.
애한토목학회 논문집, 1998. pp.483-494

9.
대한토목학회 논문집, 1998. pp.411-421

10.
1999년도 봄 학술발표회 논문집, 1999. vol.11. 1, pp.774-780

11.
콘크리트구조설계기준, 1999. pp.66-67