Types of steel structural steel beams

Steel beam in steel structure building is the top priority to determine the life of a building, in many steel structure companies, Xirong steel structure can promise to customers: the main steel structure warranty of 50 years. The main steel structure mainly includes steel beams, the importance of steel beams is no less than the life of a construction enterprise, the quality of steel beams determines the quality of steel structure buildings. Therefore, we must understand the classification of steel beams, to understand what type of steel beams should be used for what kind of building, and the selection of correct and appropriate steel beams can not only be more reasonable in design, but also control the cost of the entire building. Xirong steel structure construction for you to sort out the classification and scope of application of various steel beams in the steel structure.

The solid belly bending member (lattice type truss) that mainly bears the transverse load in the steel structure is called the steel beam, and the main internal forces are bending moment and shear force. Steel beam is a kind of basic component widely used in house construction and bridge engineering. In the field of housing construction, steel beams are mainly used in building beams in multi-storey and high-rise houses, working platform beams, crane beams, wall frame beams in industrial buildings and purlins in roof systems; In the field of bridges, it is mainly used for girder bridges, long-span cable-stayed bridges, bridge deck girders, etc. in suspension bridges.

Steel beams

can be divided into two categories: section steel beams and composite beams according to different production methods. Hot-rolled steel beams are commonly used in hot-rolled I-beams, channel steel, H-beams are commonly made of hot-rolled I-beam, channel steel and H-beam [Fig. 5, 1 (a), (b), (c)], and the beams with small load and small span are made of cold-formed thin-walled channel steel or Z-shaped steel with crimping [Fig. 5, (d), (e)]. Section steel beam processing is convenient, simple manufacturing, low cost, can be preferred, but section steel is often limited by certain specifications, when the load and span are large, its bearing capacity and stiffness can not meet the engineering requirements, should use composite beam.

Composite beam is made of steel plate and section steel through welds, rivets, bolts connected, the cross-sectional composition of the composite beam is more flexible, more

importantly, it can make the material more reasonable distribution in the section, its cross-sectional form can be divided into I-shaped, grooved, Z-shaped, box beam (Figure 5.2), etc., of which the I-section composite beam welded by three plates is the most widely used, when the load is large and the cross-sectional height of the beam is limited or the torsional performance of the beam is high, the box-shaped section beam can be used.

In addition to the above-mentioned widely used section steel beams and combinations

In addition to beams, in our many steel structure buildings, there are also some special forms of steel beams: such as dissimilar steel composite beams, honeycomb beams, prestressed steel beams, steel and concrete composite beams, etc. In order to make full use of the strength of steel, steel with higher strength grade is used for the flange plate with higher force in the composite beam, and steel with lower strength is used for the web plate with less force to form a dissimilar steel composite beam. In order to increase the height of the beam and make the steel beam have a large cross-sectional moment of inertia, the section steel beam can be cut according to the zigzag shape, and then the upper and lower semi-I-shaped left and right are staggered and welded to form an empty stomach beam with a series of hexagonal holes on the web, which is called a honeycomb beam [as shown in Figure 5.3(a)].

The reinforced concrete floor slab doubles as the compression flange of the beam, and the steel beam supporting the concrete and soil slabs is used as the tensile flange of the beam, giving full play to the good compressive performance of the concrete structure and the excellent tensile performance of the steel structure. It can be made into steel and concrete composite beams [as shown in Figure 5.3 (b)]; the use of prestress opposite to the load stress symbol, so that the force of the steel beam is changed from the ordinary force from zero stress to the force from -f (Figure 5.4), which will greatly improve the elastic force range and bearing capacity of the structure and become a prestressed steel structure (Figure 5.5).

In addition to the crane beam, the wall beam can be arranged separately, and many are composed by crisscrossing and crisscrossing, this form of beam connection is called beam lattice (Fig. 5.6), the beam grid is laid with steel or reinforced concrete floor slabs that directly bear the load, constituting building (roof) covers, working platforms, etc. The main forms of beam lattice are: simple beam lattice (only main beam), ordinary beam lattice (divided into main and secondary beams) and compound beam lattice (divided into main beam and horizontal and longitudinal secondary beam). The simple beam lattice [Fig. 5.6(a)] has only the main beam, and the floor slab is directly placed on the main beam, which is suitable for the situation of small span of the main beam and simple building layout; the ordinary beam lattice [Fig. 56(b)] is set on the main beam and then supports the floor slab on the secondary beam, and this beam lattice form is widely used; the compound beam lattice [Fig. 5.6(c)] is to set several secondary beams on the secondary beam of the ordinary beam grid, with many load transfer levels and complex structure, generally only used for the situation of large span of the main beam and complex building layout.

It can be seen from the form of the beam lattice that the beam can be divided into simple support beam, continuous beam, cantilever beam, frame beam, etc. according to the support and constraint conditions; There are also many forms of loads on the beam, including uniform load, concentrated force, trapezoidal load, triangular load, etc., so the distribution of internal forces (bending moment and shear force) on the beam is also extremely diverse. In addition, the load bearing of steel beams is generally a one-way bending beam bent in one plane, and there are also two-way curved beams bent in the two main planes, such as roof purlins, crane beams, etc. are two-way curved beams. The same as the axial compression member, the steel beam design should consider four aspects: strength, stiffness, overall stability and local stability, among which strength, overall stability and locally stable bearing capacity are the ultimate states of the bearing capacity of the beam; The stiffness of the beam is the normal service limit state, and the deflection deformation of the beam is controlled to meet the requirements. In addition, the steel beam design also includes the splicing of beams, the connection of beams to beams, the connection of beams to columns, and the calculation of the connection between flange plates and web plates of composite beams.

The above is the type and scope of application of steel beams summarized by Xirong steel structure construction through 16 years of steel structure installation, design and construction experience, combined with professional steel structure knowledge. Although this knowledge steel structure is one of the many knowledge points, but Xirong steel structure construction is willing to let the steel structure peers better understand the knowledge of the professional system of steel structure through continuous summary and induction, and is also willing to make our steel structure building safer and more reasonable through such summary and sharing, and make better buildings with better design!