In this part of the book the basic questions of Structural Mechanics are consistently expounded, among them: kinematics analysis of complex structures such as complex arches and frames; the calculations of plane complex systems on strength and rigidity under static loads; the calculations of complex arches under moving load, the method of construction of lines of infl uence for internal eff orts of arches. Finally, it was consider the question about calculation the static indefi nitely complex frame by diff erent methods such as: method of forces and method of displacements.