Browsing by Author "Kalake, Refiloe"

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    Assessment of slender square/rectangular CFDST columns subjected to eccentric loading
    (Stellenbosch : Stellenbosch University, 2023-02-08) Kalake, Refiloe; Haas, Trevor; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Columns transfer loads from beams, slabs and other columns to the soil through the foundation. Thus, columns are critical members of structures that need to have sufficient strength, be robust and resistant to failure. Columns can be constructed of different materials i.e., reinforced concrete, structural steel composite section (structural steel and concrete) columns. This study focuses on a type of unique composite column construction method. This method is known as Concrete Filled Double Skin Tubular (CFDST) columns. CFDST columns have demonstrated to have a number of advantages over conventional column types (reinforced concrete and structural steel). CFDST columns can either be classified as short (stub) or slender. Short columns generally reach their loading capacity when the materials start crushing while slender columns, fail through buckling. Short columns have a slenderness ratio of less than 22, while slender columns have a slenderness ratio greater than 22. Slender columns are classified into either intermediate or very long columns. Intermediate columns fail through inelastic buckling and very long columns fail through elastic buckling. Columns can either be subjected to pure compression or compression with simultaneous tension in bending. The primary objective of this study is to develop a functional Finite Element (FE) model to accurately predict the behaviour and the ultimate loads of slender rectangular CFDST columns subjected to eccentric loading. The FE model was calibrated and validated against experimental results of two (2) column lengths at three (3) eccentricities. After developing the FE model, a sensitivity analysis was conducted to determine the effects that different parameters have on the behaviour and ultimate load of these columns. This resulted in establishing a parameter priority. Furthermore, a study on the comparison between slender rectangular and circular CFDST columns subjected to eccentric loading was conducted. The percentage change of the ultimate load subjected to different percentage changes in column parameters was comparable for both the circular and rectangular CFDST columns with similar geometric properties.