本研究探討鋼管混凝土柱基礎耐震行為，藉由9座試體之組合軸力與彎矩載重試驗，探討埋置深度、錨定螺栓與底板加勁等參數與柱基礎行為之關係。依基礎接合形式可分為U系列、S系列與SN系列試體，英文字母U為unstiffened之意，代表柱身與底板之間未設置加勁板；英文字母S（stiffened）表示柱身與底板之間設置加勁板；英文字母N則代表no anchor之意，表示底板與基礎接合無設置錨定螺栓；另外，依埋置深度的不同又可分為不埋置、0.5D、1.0D與1.5D等四種，試體編號分別對應00、05、10與15。
試驗結果顯示U系列試體其臨界埋置深度約在一倍柱深（35㎝），當埋置深度大於此值時，其破壞主要由鋼管混凝土柱控制；S系列試體之臨界埋置深度約為0.5倍柱深（17.5㎝），此值較諸U系列試體為低，顯示加勁板之施加，可減低基礎受力程度，提高基礎設計之經濟性與可靠性。SN系列試體與S系列、U系列的比較可得，以加勁板加勁，其錨定效果近似於錨定螺栓。
基礎剛性因基礎配置之不同而有差異，並隨埋置深度之增加而呈漸增現象，故可得柱基礎在不同的接合方式下，柱體與基礎接合剛性之大小，建立埋置深度與基礎剛性之關係，藉此獲致正確之結構分析基準，作為基礎設計之有效參考。

This study is focused on the seismic performance of concrete filled steel tube (CFT) column foundation. Results from nine specimens tested under combined axial and lateral forces were used to define the relationships between seismic performance and structural parameters, such as the embedment depth, anchor bolts and stiffeners. The specimens can be classified to serial U, serial S and serial SN based on their foundation connections. Alphabet U indicates "unstiffened", maens the base plate without stiffeners. Alphabet S indicates "stiffened", means using stiffeners between the base plate and the CFT column. And N indicates "no anchor", which means the base plate without anchor bolts. Furthermore, the specimens are also classified into four different embedment depth : unbedded, 0.5D, 1.0D and 1.5D (D is the width of the CFT column), indicated by number 00, 05, 10 and 15. The result of tests shows the critical depth of embedded of U serial specimens is around 35㎝ (1D), and the damage is controlled by the CFT column when embedded deeper than critical depth. Meanwhile, the critical depth of embedded of S serial specimens is around 17.5㎝ (0.5D). The small critical depth number shows the employ of stiffener can reduce the damage level of foundation and enhance the economy and reliability of foundation design. The comparison of serial SN, serial S and serial U shows the effect on anchor by stiffeners is similar to anchor bolts. The rigidity of foundation differs by foundation connection and enlarged by the increase of the embedment depth. Therefore the relationship between the embedment depth and the rigidity of foundation can be established by foundation connection. The analysis principle can be obtained then appropriate for foundation design reference.

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