Game with forms.
The rigidity of the beam also depends on the shape. Since the layers are included in the work, the most remote from neutral, they need to strengthen. Check this by conducting the following experiment. Put a sheet of paper on two books between which free space remained. You can’t put a single large object in the place of this gap on such a thin beam so that the structure does not break. And now put a sheet of paper in an accordion, and now it already has a different rigidity, strong stretching, the surge resists only the lower and upper ribs of this multiple beam, the flat surface serves only for the connection between them. This principle underlines the architectural breakdown of the double -rotary section, its shape, which you met many basic structures of metal beams. The wide supports of the double-barrel beam are opposed by the force of stretching and the sabotage, and the vertical part of the rally can perform the function of their connection with the neutral layer. The material is saved, the design is facilitated, and the rigidity is facilitated. In construction, beams with triangular compounds called farms are often used. Inclined beams carry a roof, which in turn should withstand a layer of snow. The farm can be compared with the circul, the top of the farm — its hinge, and two side beams — the legs of the circul. So that the compass is not revealed when it presses on a hinge connection, it is enough to connect the ends of the legs with a rope that will withstand stretching. The same thing happens when the beams are connected to the triangle. The horizontal beam of the farm also works for stretching. So, it can be replaced with a thin steel rod. That is why the principle made many metal structures to many. Look up under the roof of the station or market. Elements operating and stretching, beams; Elements that work only for tensile — thin hands or slings Dyneema.