Symmetric frame with two racks. The capture and suspension in a few points is a simple case is to climb a symmetrical frame with two racks, which is enough to capture at two points. In this, as in the previously described case, in the process of lifting, statically determined efforts arise. Although the Ragel of the frame is captured at two points, the traverse, to which it is attached, is suspended at just one point. Since the frame under consideration has two racks, then its lower part, accordingly, is based on two points. Due to the fact that suspension is carried out taking into account the position of the center of gravity, t. e. In the axis of symmetry of a symmetrical frame, you have to ensure that the racks placed on the roller cart are evenly approaching the foundations. In this case, there will be no efforts of twisting and deformations that they cause. However, when the suspension point is not exactly above the center of gravity or the heels of the columns are unevenly approaching the foundations, the power efforts appear in the frame, as a result of which unwanted deformations arise. As a result of these phenomena, cracks may form that reduce the strength of the element. This shows that the installation of frame structures should be carried out with maximum caution. The rise in the structure is significantly complicated if the seizure of the crossbar at two points is insufficient and in order to avoid additional reinforcement, it is necessary to capture in a larger number of points. The rise becomes even more difficult if the frame is asymmetric and has on any side in a horizontal or vertical direction the console protrusions.
