A plate girder is a steel beam often used in bridge construction. Depending on the design requirements and type of structure, metal thicknesses for web, flanges, stiffness, etc. are determined.
Using the right material (steel) with the specified strength and carrying out welding work are the two main factors that must be considered when developing the sheet metal beam.
A sheet metal beam is used when we need deeper sections with greater rigidity to support heavy loads.
Furthermore, there is a limitation in the production of hot-rolled profiles as the profile depth increases. Therefore, we need to use composite profiles that can accommodate large bending moments and shear forces.
Types of license plate holders
Depending on the standards used or the way the beams are manufactured, there may be different classifications.
There are two types of sheet metal beams.
- Inverted license plate holder
- Welded plate beam
Inverted license plate holder
It is a combination of flanges, webs and other necessary rigidity elements. The connection is mechanical, the panels are not welded together.
- In general, 90% of the cutting forces are supported by the web.
- The connection between the web and the flange is stabilized by the angular profiles recessed into the flange. Setbacks must be sized for horizontal shear.
- Connections between web and flange angles must be designed to withstand horizontal shear forces and vertical loads acting on the flange when transferred to the web.
- Angular profiles are used as web stiffness in reversible beams.
Welded plate beams
Welded plate beams are the most commonly used in construction because they are easier to manufacture and are a much more efficient type of beam.
These profiles are mainly used in bridge construction. The plate girder bridge is very rigid and can accommodate very high loads while supporting lateral movements. This effect can be observed in railway bridges. Furthermore, they are used to develop box beams.
Empirical methods or approximation methods are available to determine the total height of the sheet metal beam as well as the thickness of the flange and web.
Sheet Metal Beam Components
A conveyor essentially consists of five components. Assembling these five components creates the complete beam. The basic requirement is to produce an I-beam that, in addition to other local buckling resistances, also has very high flexural and shear stiffness.
- web board
- table
- Reinforcements (support, longitudinal and intermediate reinforcements)
- Flange and core connectors
- End connection
web board
The vertical plate of the beam is called the web plate.
Thickness depends on project requirements and height is also determined based on site conditions and network loads.
The web normally supports the loads applied to the flange in the form of shear forces. The web effect is generally not taken into account when designing the bend.
As the layers become thinner and taller, the fabric tends to buckle when stresses are applied. Therefore, various types of stiffness discussed in this article are welded to the fabric to ensure its strength.
table
There are no special features other than using a separate plate for the flange. The flange plate is welded or otherwise connected as described under the different types of plate brackets.
Unlike rolled profiles, we connect the web and flange to form the sheet metal support.
The flange is designed to withstand bending action. Depending on project requirements, additional reinforcements or plates are provided.
reinforcements
The reinforcements serve to improve the load capacity and avoid local buckling errors. Furthermore, they are used to absorb the loads acting on the beam until they are distributed throughout the beam.
The following types of reinforcement can be observed with these types of steel elements:
- Bearing reinforcements
- Longitudinal reinforcements
- Intermediate stiffeners
Bearing stiffeners are attached to the support to distribute the reaction from the support to the web without causing buckling errors. In addition to the bearing stiffeners, there is a lifting stiffener for installation purposes, as shown in the following figure.
To reinforce the web, steel plates welded in the longitudinal and transverse directions are also used.
Vertical or transverse reinforcements are observed in most steel beams that support heavy loads.
Flange and core splices
It is the top connection between the web and the support flange.
If the length of the beam is less than the span, a butt connection is required.
This is a torque and shear transfer connection that ensures the beam continues.
End connection
The final connection is the most difficult part of the structural detailing of a steel beam.
If there are continuations or we support the beam on a support, the connection must be designed accordingly.
In most cases, however, the sheet metal beams are simply stored in the end support. In such situations we need to provide the reinforcements at the end joint.
A similar construction procedure is followed in the design of the end plates and reinforcement that vertically connects the web and flanges.
Application of sheet metal beams
Sheet metal beams are used as support structures in different areas. The following areas should be highlighted as main areas of application.
- Bridge construction
Plate girders are mainly used in railway and highway bridges. Old railway bridges in particular are lamellar girder bridges.
In addition, box girder bridges, girder bridges, composite military girder bridges and semi-box girder bridges are considered as possible uses.
- Ships
- Portal beam
- Oil and gas platforms
- Stress Test
- Cranes
- Lifting structures
Advantages of license plate holders
- They can be used to transport heavy loads
- Quick build
- Grater stability
- High resistance to fatigue fractures
- Simple construction compared to truss bridges
- Easy to maintain
Disadvantages of license plate holders
- They cannot be used to support large spans
- Less architectural appearance
- A little difficult to handle when inserting
- Production must be carried out strictly in accordance with the project.
The articles were written in Construction of steel beams in accordance with BS 5950 E Worked example of construction of a steel beam (universal beam) For more information on steel beam structures, see this page.
For more information about steel beams, see the article Types of Steel Beams .
