This thesis presents the results of numerical analysis on the structural performance of an innovative design for the external semi-rigid composite connections. A parametric study of an innovative design of external semi-rigid composite joint, in which the central reinforcement are provided with a head to remove the conventional cantilever needed to ensure sufficient anchorage length for the reinforcement, is carried out. The performance of the joint was evaluated in terms of moment-rotation curve in order to explore the effects of shear studs, the reinforcement ratio, slab thickness, and concrete strength. In addition, the effect of profile sheet is also examined. The composite connection which consists of I section column and beam, bolts, endplate, and slab were simulated in three dimension finite element software, ABAQUS. In the model, material and geometrical non-linearities are considered. The finite element model was calibrated by previously tested experimental data, briefly reviewed in this paper, and verified that the numerical model can simulate and analyze the overall and detailed behavior of different types of the composite connections. The results are examined with respect to the ultimate moment capacity failure modes, the initial stiffness, and the rotation capacity. According to the analytical result the increase in reinforcement ratio and thickness of slab can improve the initial stiffness and the moment capacity of the joints effectively. The initial stiffness and the moment capacities of the joints increases by increasing the number of shear studs up to certain limit but further increase doesn’t show any change in both features. The presence of profile sheet and the increase in the strength of the concrete increases the initial stiffness and the moment capacity of the joints less efficiently. However, the increase in strength of the concrete and ratio of the reinforcement doesn’t show any clear trend on the rotation capacity of the joints. In the other hand, the presence of a profiled sheet, the increase in the thickness of the slab and the increase in the number of shear studs show a decrease in the rotation capacity of the joints. In general, the analytical result shows that some of the parameters considered have significant influence while others have slight effect on the behavior of external semi-rigid composite connections.