This chapter focuses on the superposition of the bar and the thin beam element. Based on the combined basic equations of continuum mechanics, i.e., the kinematics relationship, the constitutive law (here: one-dimensional Hooke’s law for isotropic materials) and the equilibrium equation, the partial differential equations, which describe the combined structural element, are derived. In addition to the classical notation, a formal notation is introduced. Thus allows to highlight the similarities between the different structural members.