鉛直荷重を受ける杭支持独立フーチングの終局耐力に関する研究 -I : 4 本杭支持独立フーチングの実験結果について

抄録

This paper reports the results of experimental work on the reinforced concrete four pile caps under vertical load. Twenty square pile caps were tested. The variables involved were position of piles, ratio of reinforcement and side length of column. For fourteen pile caps final failure was in shear and for the others it was in bending. In shear failure two distinct forms were recorded. The first was a punching failure by the column punching through the pile cap. The second was similar to that in a wide beam, with the pile cap splitting into two halves which were displaced vertically relative to one another. In regard to the ultimate strength the results of the test were compared with the values calculated according to the equations proposed by others, to the provision for the moment and shear in A. I. J. Building Code Requirements for Reinforced Concrete (1975) and to that in A. C. I. Building Code Requirements for Reinforced Concrete (ACI 318-71). To conclude the discussions the authors point out that the prevision for moment in A. I. J. Building Code 1975 leads to a noticeable error toward the dangerous side in the case where piles were set at each corner of pile cap.