中空雙鋼管混凝土複合構材（CFDST）應用於高層結構與橋柱具有極大的潛力，當地震發生時構材常須承受扭矩或與扭矩耦合之組合載重。此研究針對圓形中空雙鋼管混凝土構造進行一系列之彎矩與扭矩組合載重試驗，藉以探其耐震性能。 由實驗結果可知，在相同外徑尺度下，中空雙鋼管混凝土複合構材之強度、勁度與能量消散能力均較鋼管混凝土為佳。由實驗結果亦發現，當斷面空心比增大時，構材之能量消散能力降低，其勁度遞減率隨之增大。 本研究亦依據實驗結果，提出彎矩與扭矩組合載重下之強度互制公式，以提供工程設計參考。 Concrete-filled double skin tubes (CFDST) have a great potential to be applied in the construction of high-rise buildings and bridge piers. In practice, columns often bear additional torque when earthquake occur. This paper describes a series of torsion-bending combined loading tests carried out on CFDST, both outer and inner are circular hollow section. Purpose of this study is to investigate their seismic performance experimentally. The two test parameters of this research considered were a sectional void ratio and an eccentric ratio of loading. As a result, CFDST members were found to have significant increase in strength, stiffness, ductility and energy absorption compared with the same dimension circular concrete-filled tubular members, it also showed that the energy absorption capacities decreased when sectional void ratio increased, and further verified from response comparisons that the members’ stiffness deterioration rates were increased when sectional void ratio increased. The purposed methods for ultimate strength predictions of composite members were in good agreement with the experimental results. Finally, a simplified expression for composite members’ stiffness evaluation was proposed for engineering references.
