On the Deformation Limit of Concrete Beams Under Bending

Abstract

It is well known that concrete fails at a stress smaller than its static strength, when subjected to sustained or repeated load. But the information on failure of concrete under these loads is meager, and the information on ability of concrete to resist these loads has never been established to the extent which it can be accepted without question.In this paper, the stress-strain relation for concrete beam subjected to flexure was studied and the following conclusions were obtained.(1) The relationship between flexural stress and tensile strain, plotted on logarithmic graph, is rectlinear up to a certain point, and at this point, the slope of stress-strain relation varies abruptly.(2) Test Results show that the strain corresponding to the first point at which the slope of stress-strain relation varies represents maximum deformation which concrete is capable of developing without undesirable effects.Then, the author named it "deformation limit" of concrete.

Uniaxial Tension Test of Slender Reinforced Early Age Concrete Members

“…Figure 10 presents the relationship between splitting tensile strength and cracking stress that reaches maximum stress under uniaxial tensile loading. Yoshimoto proposed an empirical equation given in Equation (4) for such a relationship [ 23 ]. It should be noted that the object of his study was mature concrete, and the equation was proposed based on a direct tension test using concrete only f t 1 = 1.277 · f t 2 0.814 where f t 1 is the cracking stress (MPa), and f t 2 is the splitting tensile strength (MPa).…”