الفهرس 
Chapter One IntroductionOnly 14 pages are availabe for public view
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Abstract
In the realm of tall buildings and high seismic regions, CFST columns have gained popularity due to their advantages: high strength, ductility, and fire resistance. They offer economical and rapid construction as the steel tube acts as formwork and reinforcement for the concrete core, while providing confinement. The concrete core enhances the steel tube’s resistance against buckling. However, limited information on CFST column connections hinders their widespread use. Current base connection designs often require thick base plates and numerous anchor rods, which can be uneconomical. This study aims to assess the effectiveness of three enhancement techniques (implanted rebars, steel hoops, and vertical stiffeners) for improving the performance of CFST column embedded connections in RC footings under static and cyclic loads. Experimental investigation was conducted on four CFST embedded column-to-footing connection samples using implanted rebars and stiffeners techniques under static lateral load. Furthermore, a parametric study was performed using ANSYS 2023 R1 software to analyze the connection behavior under both static and cyclic loads through a Finite Element Analysis (FEA) model. The implanted rebars increased the moment capacity by a factor of 1.1-1.5 and ductility by a factor of 1.05-1.35 under cyclic load conditions. Under static lateral load, the moment capacity increased by a factor of 1.1-1.58, and ductility increased by a factor of 1.26-1.86. The steel hoops technique was more effective in terms of ductility since the ductility increased by factors that reached 2.1 and 2.25 while the moment capacity increased by factors that reached 1.32 and 1.51 under static and cyclic loads, respectively. The stiffeners technique showed modest contributions to both moment capacity and ductility. Furthermore, a chart was proposed to simplify the choice of the best combination of the parameters of each technique for future designs. The results suggest that the implanted rebars and steel hoops techniques offer promising approaches for improving the connection strength and ductility of CFST columns, while maintaining cost-effectiveness.