曲げモーメントとせん断力をうける角形鋼管柱の埋込み形式中柱柱脚部における力学性状 : その2 初期剛性と終局耐力および応力伝達機構

Abstract

On the basis of this study, the following conclusions may be drawn concerning steel square tubular column bases embedded in concrete footings. (1) In the case without any reinforcements, when the embedment length is long enough, the stiffness of the column base connection is equal to about half of that of steel column fixed at the top of the footing. (2) In calculating the displacement of the column, the depth of the apparent fixed end is 1 D to 1.5 D. (D : Depth) (3) The maximum concrete bearing strain near the embedded square hollow structural sections under the horizontal loads occurs at the both corners of the sections. However, the bearing condition is improved by filling with concrete. (4) In predicting the strength of the embedded square hollow sections when governed by concrete failure, the effective width coefficient should be taken as 3.0√<t/W> (t : thickness, W : width) to give an equivalent width coefficient. This coefficient is should be taken as 0.9 when the hollow sections are filled with concrete. (5) The ratio of the resistance moment at the base plate to the maximum moment of the column beneath the top of the footing is influenced by the embedment length. In the case of the embedment length longer than twice the tubular depth, the ratio is comparatively small.