In the last decade, the use of fiber reinforced plastic (FRP) composites for reinforcements to concrete members has emerged. In previous works, some design of FRP rebar that reinforced in the concrete has helical winding and some with sand coating on the outside. Different from the case of steel bar, the helical ribs here are wound on top of the bar after the bar has been pultruded. The bond between these ribs and the main bar is made of secondary bonding.  This thesis introduce a new design consists of a regular rod but it also has lobes along the rod that give the rod a wavy configuration. The reinforcement is continuous throughout the rod and the wavy part contains fibers that are part of the main rod (Rather than just bonded in). This mechanical interlock does improve the shear load transfer between the FRP rod and the concrete. The objective of this thesis is to optimize the shape of the FRP bar. Straight FRP bars and bars with circular-shaped lobes, elliptical-shaped lobes will be compared. The computer program ANSYS has been used for the finite element analysis. Optimization of the shape of the FRP bar will be discussed and the optimized shapes of the bar will be introduced.