الفهرس 
CHAPTER(1): INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Concrete-Filled Tubular (CFT) steel composite columns combine the advantages of steel members, high tensile strength, ductility, the advantages of concrete members, high compressive strength and stiffness. Improving the CFT column behavior strength is the demand of structural engineers. The study presented the effect of adding different types of longitudinal stiffeners on the behavior of CFT columns. The study also investigated different parameters such as the number, the dimensions and the shape of stiffeners. The load-displacement behavior of the columns, strength of the columns and failure mode were evaluated from the experimental and numerical investigation.
Experimental tests that included five CFT specimens were carried out to study there behaviors up to failure. A numerical model was employed using finite element method to simulate the behavior of circular concrete-filled tubular steel columns with longitudinal stiffeners. The nonlinear analysis was performed using ABAQUS and the finite element model was validated and verified against the test results conducted in this study. The failure modes observed during the tests were compared with those obtained from the numerical analysis.
An extensive parametric study was performed using the verified numerical model to include realistic scale models besides enlarging the experimental test program to investigate the above mentioned parameters.