鋼管混凝土(Concrete Filled Tube，CFT)柱可提供高強度、韌性及耐震能力，除了提升相關力學性能外，可避免模板更換使用，進而減少大量的施工時間。然而隨著經濟社會的發展，對工程結構性能的要求不斷提高，鋼管混凝土需要引進越來越高性能的混凝土材料。超高性能混凝土(Ultra-High Performance Concrete，UHPC)憑藉著優於傳統混凝土的力學特性與耐久性能而備受關注。然而其固有的脆性讓實際應用遭受阻礙，鋼管填充超高性能混凝土(UHPC Filled Steel Tube，UHPCFST)柱能有效圍束限制UHPC脆性破壞，形成高強度、延展性的高性能構件。本研究的目的是採用數值建模軟體Abaqus來進行3D 非線性有限元素分析，對承受單軸壓力荷載的UHPCFST柱進行數值模擬，為驗證有限元素模型，將數值分析結果與實驗數據進行比較，探討UHPCFST柱模型在不同圍壓和柱的幾何特性下的影響。

Concrete-filled tube (CFT) columns are renowned for their excellent seismic resistance, providing high strength, high ductility, and substantial energy absorption capacity. Besides enhancing structural properties, CFT columns expedite construction by eliminating the need for permanent formwork. The evolving demands for high-performance engineering structures, driven by economic and societal advancements, necessitate the incorporation of ultrahigh-performance concrete (UHPC) into concrete-filled steel tube structures. Ultrahigh-- performance concrete has garnered significant attention for its exceptional mechanical strength and long-term durability compared to conventional concrete. However, the inherent brittleness of ultrahigh-performance concrete poses challenges for practical applications. Ultrahigh-performance concrete-filled steel tube (UHPCFST) columns mitigate this brittleness, preventing brittle failure in non-reinforced columns and forming high-performance members with improved strength and ductility. The aim of this investigation is to employ the nonlinear finite element program ABAQUS to perform numerical simulations of UHPCFST columns subjected to axial compressive loads. To achieve this goal, proper material constitutive models for steel tube, and ultrahigh-performance concrete are proposed. Then the proposed material constitutive models are verified against experimental data. Finally, the influence of the concrete confining pressure and the geometric properties of the columns on the uniaxial behavior of UHPCFST columns are studied and discussed.

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