I-beam is mainly divided into ordinary I-beam, light I-beam and wide flange I-beam. According to the height ratio of flange to web, it is divided into wide, medium and narrow flange I-beams. The specifications of the first two are 10-60, that is, the corresponding height is 10 cm-60 cm. At the same height, the light I-beam has narrow flange, thin web and light weight. Wide flange I-beam, also known as H-beam, is characterized by two parallel legs and no inclination on the inner side of the legs. It belongs to economic section steel and is rolled on four high universal mill, so it is also called “universal I-beam”. Ordinary I-beam and light I-beam have formed national standards.
Whether I-section steel is ordinary or light, because the section size is relatively high and narrow, the moment of inertia of the two main axes of the section is quite different, so it can only be directly used for members bent in the plane of their web or form lattice stressed members. It is not suitable for axial compression members or members with bending perpendicular to the web plane, which makes it very limited in the scope of application. I-beam is widely used in buildings or other metal structures.
Due to the relatively high and narrow section size of ordinary I-beam and light I-beam, the moment of inertia of the two main axes of the section is quite different, which makes it very limited in the scope of application. The use of I-beam shall be selected according to the requirements of design drawings.
When selecting I-beam in structural design, reasonable I-beam shall be selected according to its mechanical properties, chemical properties, weldability and structural size.