In engineering construction, material’s strength and the cost are the main parameters to be considered when selecting a particular material. Another important aspect in structural engineering the design. Structures should be designed in such a way that no failure occurs in future. For instance, for the I- Section given, there are two possible stresses. Compressive stress and tensional stress. In designing, the least possible stress should be used for safety.
From the stress distribution diagram, it can be seen that stress is zero at the beam axis. This therefore, makes an I-Section the best beam for structural engineering. When the beam bends, the top most fiber is in compression while the bottom most fiber is in tension. The stresses are greatest at the top and the bottom fibers. I-section provides the stiffest beam with the least amount of material. This is because it only requires more materials at the bottom and top flanges. The diagram below shows a cross section through an I-section.
This shape is used when the load is parallel with the flange. As you can see, the shape is not so good with lateral forces unless you turn it sideways. When the load will come from two directions, a square tube is used. The section is normally designed so as to minimize materials on. This type of section is better than other sections due to the fact the maximum beam stiffness is achieved with minimum