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1 実験計画と荷重-変形関係

Abstract

A total of 93 steel column bases were tested. The study was composed of two main groups : one was undertaken to examine the bearing mechanism, and the other was the effects of the reinforcing methods on the strength, stiffness and hysteretic characteristics of the connections. For the former, the variables considered were : (1) embedment length. (2) width to thickness ratio, and (3) concrete filling. For the latter, the main variables were : (4) size and thickness of base plate, (5) spacing between anchor bolts, (6) hoops, (7) rib, and (8) welded reinforcements. In this paper, the test program and the load-displacement relationships are reported. The results may be summarized as follows : (1) The load-displacement curves show the slip type, when the embedment length is short. (2) The presence of anchor bolts or base plate has little effect on the load-displacement curves, when the embedment length is twice the tubular depth. (3) The presence of welded reinforcements, welded rib or concrete filling slightly increases the stiffness of the connections. These hysteresis loops indicate more stable softening type as compared with the loop without any reinforcements. (4) In the case of unreinforcement, the needful embedment length to take the form of a plastic hinge in steel column at the maximum load is influenced by width to thickness ratio, existence of concrete filling, yield point of the steel column, and compressive strength of the concrete.