Abstract
In this paper, the theoretical explanation on the phenomenon which the compressive strength of concrete specimen varies with the ratio of hight to width of specimen is attempted with application of the simple theory of plasticity. The value of the compressive strength of the test specimen is calculated with the component of stress on the osculating plane of the specimen and the loading plate, at the time when the plastic zone is connected in the specimen, and the specimen become unsteady state as a whole. The analysis of the plastic stress is done as the statically determined plane plastic strain problem. Consequently, it was found that the quantative explanation of such a phenomenon of compressive failure of concrete specimen was possible, if the analysis by means of the yield criterion of cycloid-type was applied.
