Steel sections are contrived and shipped to some standard lengths, as governed by rolling, transportation and handling restrictions. Most of the structural steel members used in constructions have to span great lengths and encircle large three-dimensional spaces. Hence connections are essential to amalgamate such spatial erections from one and two-dimensional elements to bring about the stability of structures under different loads. Thus, links are essential to creating an integral steel structure using separate linear and two-dimensional (plate) elements.
Design of connections in metal beam structures is an integral part in the design of steel constructions. They are the critical components of steel structuring and designing. Hence, a good understanding of the behavior and design of joints and connections in steel structures is an essential prerequisite for any project engineer. Let's know more in detail about the various types of steel beam connections and their uses.
Connections in Metal Beam Structures
Links are generally made by bolting or welding. Bolting is common in field connections since it is economical and easy to make. Bolting regards as more appropriate in field connections from consideration of safety. However, welded connections are easier to make and more efficient.
There are many types of steel beam connections used in metal beam structures. Steel beam connections branches into two groups, Framed and Seated Connections.
In the framed steel beam connections, the beam connects to the supporting steel element through fittings. Whereas, in seated connections, the beam fixated on the seat is similar to the case where the beam places on masonry walls.
Now let us discuss the different types of steel beam connections.
- Bolted Steel Beam Connection: There are two types under this, framed and seated.
Framed steel beam connections: Steel beams links to supporting elements whether it is steel girders or columns with web connection angle. The minimum length of the connecting angle should be half of the beam evident web depth. This measure is noted to ensure sufficient stiffness and rigidity.
There are numerous standard sizes of bolted framed connections along with their capacity provided by codes. The purpose of such a standardized connection is to increase the speed of the design.
Seated steel beam connections: The most outstanding advantage of seat connection in metal beam structures is that the beam fabrication is economical, and seat provides immediate support during erection. The function of the top angle used is to prevent the metal beam structure to suffer from accidental rotations. This type of connection does not need shop detailing. Bolted connections desire environmental point of view because the structure dismantles, and elements are used in other projects. Additionally, bolted connections erect with great ease.
- Welded Steel Beam Connection: These also have two types, framed and seated.
Framed steel beam connections: Various sizes of welded framed connections with their capacities are accessible and provided by digits. The weld of the connection is prone to direct shear stress. The stress caused by loads on the beam affect weld pattern. So, these stresses require consideration. Part of the welding performed in the field is challenging as it is difficult to achieve high-quality weld due to movements of steel members caused by winds or other factors.
Seated steel beam connections: This is similar to bolt seat connection, but welding is used for fastening rather than bolts. The loads on the metal beam structures affect the weld pattern oddly and generate weight. So, like welded framed connections, such weights require consideration too.
- End Plate Steel Beam Connection:
A flexible end plate connection consists of a plate fastened to both sides of the web in metal beam structures by fillet welds. The connection should transmit vertical shear and allow beam end rotations to occur without the development of significant moments. They provide moment-resistant connections between beams and columns at the corner of frames or a moment resistant connection to elongate beams.
Typical flexible end plate connections may be partial depth or full-depth and are welded to the supported metal beam structures. The beam then bolts to the supporting beam or column on site.
This type of connection is relatively low-priced but has the disadvantage of little opportunity for site adjustment. The overall beam lengths need steel fabrication within tight limits, although packs are used to compensate for fabrication tolerances and erection tolerances.
End plates are used with skewed beams and tolerate moderate offsets in a beam to column joints. The end plate is connected to the metal beam structures through weld because its capacity and size are managed by the sheer magnitude of the beam adjoining the weld. The stress applied to the connection at the end of the member does not have eccentricities. There are various types of end plate connections including a flexible, semi-rigid, and rigid end plate connections.
Fabrications and cuttings should be conducted with great care to avoid errors. For example, cutting the beams to length must be as exact as possible. End plates weld transversely to the web of the beam and then bolted to the supporting member. This should provide effective, simple connections to transmit shear.
End plate connections are unsuitable for tall steel structures.
After keeping in mind the above technicalities, it is essential to adhere to the strictness of each dimension and connection. Steelwork connection generally produces the most economical steel frame. A diversion in this connection will inevitably increase overall cost. The need for individual connections could be avoided by judicious selection of member sizes.
When designing individual connections, it is possible to use a modified version of one of the standardized connections. Therefore, always check design principles and component sizing rules.
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