對於單柱系統，多維㆞震力㆘容易產生彎矩及扭矩組合載重，減 低構件強度與韌性。於耐震設計㆗，鋼管混凝土柱於為㆒良好的複合 構件型式，藉由包覆鋼管提昇混凝土強度並減緩混凝土開裂後強度之 衰減，但兩種材料間之交互作用相當複雜，因此本研究針對其斷面形 式、材料組成比例進行探討以期掌握最佳之斷面配置。 研究㆗定義㆒斷面形狀因子f，為極限彎矩強度與降伏彎矩強度 之比值，並針對㆕種不同形狀之鋼管混凝土柱進行㆒系列實驗，探討 構件材料、尺寸等效應外形狀因素與複合構件強度、勁度、韌性行為 之影響。研究結果顯示，所定義之形狀因子對構件降伏後結構行為有 ㆒定程度代表性。在偏心載重㆘，斷面形狀因子愈大其勁度衰減愈 緩，強度及位移韌性衰減愈大，能量消散能力損失愈多。於扭轉行為 ㆗，形狀因子愈大軸力於扭轉強度、非彈性勁度衰減之減緩貢獻愈大。 Concrete-filled tubes (CFT) are suitable structural forms for earthquake-resistant designs. The infilled concrete provides effective compressive strength and lateral support to the steel tube so that tube local buckling can be delayed and member ductility can be achieved. It has been found in previous study on steel-concrete composite behavior that the performance of member under combined loading, particularly coupled with torsion, is affected by the sectional configurations. Therefore, study on the effect of sectional geometry on the seismic performance of CFT members is also essential. This study is focused on the experimental investigation of relationship between member performance and the section’s shape factor. Test results show that the stiffness deterioration rates increase when the sections’ shape factors decrease. It is also found that the losses in strength and energy dissipation capacity for members subjected to loading combined with torsion are more significant when the sections’ shape factors increase
