Abstarct: Abstract The use of strut-and-tie models serves as an effective approach for designing concrete members or portions of members that exhibit a nonlinear strain distribution along the section depth. In strut and tie models, the complex mechanism of force transfer is simplified through a truss-like idealization. The objective of this research is to derive strut and tie models by employing topology optimization aimed at minimizing strain energy under a material volume constraint. In this context, the developed algorithm is capable of determining the optimal material distribution within the design domain so that the objective function is minimized. Subsequently, the tensile and compressive members are extracted from the optimized topology, and the corresponding strut and tie model is proposed. In this thesis, multi-material topology optimization is investigated with the objective of minimizing the strain energy under a material volume constraint, using two distinct approaches. In this context, the developed algorithm is capable of determining the optimal distribution of two materials within the design domain in such a way that the objective function is minimized. In the first approach, each finite element possesses two design variables: the first indicates the presence or absence of material in the element, while the second specifies the type of material assigned to it. In the second approach, each element has a single design variable, and the distribution of concrete and steel materials is determined baxsed on the first invariant of the stress tensor for each element. The topology optimization problem is solved using the Solid Isotropic Material with Penalization (SIMP) method and the Method of Moving Asymptotes (MMA). To calculate the derivatives of the objective function and the volume constraint with respect to the design variables, analytical sensitivity analysis is conducted. In this study, the Python programming language is employed to implement the topology optimization problem, while the finite element software Abaqus is utilized for structural analysis during the optimization process. The contributions of this thesis include presenting a general formulation for multi-material topology optimization in plane stress problems, bending plates, and shells using the Method of Moving Asymptotes, as well as proposing a method for deriving strut and tie models through two-material topology optimization.