鐵筋콘크리트 部材의 應力傳達機構에 關한 硏究 = Studies on an Analogical Analysis of Stress Transmission in the Reinforced Concrete Members

다국어 초록 (Multilingual Abstract)

Topics of investigation in recent years on the mechanism of reinforced concrete beams have mainly concerned with either be??ing and shear resistance of the reinforced concrete beams under the action of guasi-static monotonically increasing load is already applicable.
In addition, and analogical analysis of stress transmission in the beams is intended.
This paper presents the results of following behaniors.
(1) The bending strength of beams observed in the tests was generally larger than the values estimated by umom??ra's formula of evaluating the ul??tmate strength of rein forced concrete beams. The amount of these hyper-resista ?? change with the rati of span length to the depth of beams.
(2) Shear resistance of beams with out web reinforcements is largely, infleunced by the types. of loading and the condition of supports. The relation between these types of strength behavious and those of restrained beams subjected to aconcenfrated load at the midspan was obtained.
when the soan length of test specimen is considerably large, the test result becomes smaller than the strength estimated by conventional theory. The coelficient compensating the discrepancy between the estimated streagth and the test result was experimentally derived. And so??ne dis??ussion on the expected safety factor of the conventioanl formula was given. In another series of test by Ban, the strain disfribution of tensile reinforce nents of beams which was subjected to a concentrated load was measured over the entire length of beams. The main results by these tests were as follows;
a) There is a distinct discrepancy between the critieal loads of yielding observed in the strain of the tensile reinforcement and those observed in the deflection of a beam
b) A remarkable growth of tensile stress in the remforcement at the point of the support is observed after the deflection of the beam reaches a certain degree. Since the bend stress about the crack of the midspan does not decrease at all. it is considered that the local tensile stress at the point of support was not brought out by release of the bond stress in the middle ?? a ?? of the beams. Those facts suggest that the stress distribution in reintorced concrete beams is considerably different from the result derived from the flexural theory of ordinary elastic beams.
In order to explain these experimental facts, a modified arch or truss analogy concerning the meachan??sm of stress transmission was proposed, and fundamental formula of bending strength of beams were derived. The results calculated by those formula are in good agreement with the experimental values obtained from various loading conditions. A rational explanation of the characteristics of shear resistance and formation of shear cracks can successfully be given by the application of the presented arch analogy concerning the mechanism of stress transmission.