The physical essence of the “nagel effect” for main reinforcement in a spatial crack of reinforced concrete structures under the action of bending and torsion for the model of reinforced concrete structures deformation involves the formation of the first block and the second block of a spatial crack. The second block is located on the upper surface of the longitudinal reinforcement to the surface of normal stresses and the resultant force from crushing concrete and a special adhesion force to the surface of the reinforcement (and the additional effect of breaking the continuity) in the eccentricity to its center of the axis of the reinforcement for distributed variable bending moment (through the calculation of statically indefinable systems for the force method). It is important to allocate a special area of the left side for the longitudinal reinforcement in the first block of separation and the formation of a new longitudinal crack, which removes surface normal and tangential of stress adhesion. Consider the scheme-a beam with two fixed ends: to calculate it, take the main system obtained as a result of making a cut in the middle of the beam for given unit diagrams of bending moments: under the action of a vertical load; with linear displacements of the fixed ends (normal to the beam axis); with rotations of the fixed ends in construction mechanics.