Hybrid Composite Reinforcement Strategies for Large-Scale FDM Additive Manufacturing The rapid growth of the 3D printing has opened new possibilities to fabricate structural components through large scale additive manufacturing. The primary aim of this thesis is to address one of the most important challenges in Fused Filament Fabrication (FFF): poor interlayer bonding, which often leads to weak mechanical properties, especially in perpendicular direction to the printed layers. The other goal is to investigate reinforcing strategies that enhance the feasibility of utilizing 3D-printed components in structural applications, such as small-scale pedestrian bridges. Different hybrid reinforcement strategies were conducted to improve the quality of 3D printed component.