Does your industrial project include steel trusses and what kind of steel trusses are suitable for different construction projects? This guide will help you recognize some of the most common types of steel trusses and what they are typically used for.
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What is a Steel Truss?
A steel truss is a sturdy structure made of straight triangular members joined by welding. It is designed to withstand large loads and can withstand long distances. In buildings, the main function of the steel truss is to support the roof and provide sufficient strength to resist lateral forces.
The welded joints of the truss form the system’s nodes or pins. They show how the truss handles or responds to the applied weight. In addition, some steel trusses use both pins and roller supports.
Different load-bearing steel structures are required for different construction projects, such as building a roof or a bridge. Therefore, it is important to understand the types and uses of steel trusses. Keep reading to learn more about steel trusses.
Types and Uses of Steel Truss
Below are a few common types of steel trusses. They can be used to build residential roofs, commercial buildings, and other sturdy structures such as bridges:
Fink Steel Truss
If you are working on residential construction, the Fink steel truss is the best choice for roofing. With a small span of 5 to 9 meters, this truss is the most popular and economical choice for residential steel roofing. Its short, high sections form a W-shape, resulting in a strong strength-to-weight ratio.
Areas of application:
Fink steel truss is the best choice for supporting the roof of a house. This is because it can effectively support the weight of the upper portion of the roof. These types of loads include:
- The weight of the roof, including shingles or insulation.
- Live loads caused by roof movement.
- Accumulated snow or strong winds.
Pratt Steel Truss
If your building project has a span of between 20 and 100 meters. Then Pratt steel truss is the best choice for steel roofing. It has top and bottom horizontal beams with vertical and horizontal sections forming an “N” shape.
Since this steel truss has compressed vertical members and tensioned diagonal members, fewer diagonal members can be used. This not only reduces the price but also improves the performance by reducing the weight.
Areas of application:
Pratt steel trusses are suitable for long roofs that are primarily subject to deadweight or lifting forces. For example, prefab steel airplane hangars are open buildings with long-span roofs. They are constructed with Pratt steel trusses that can withstand strong upward forces.
North-light Steel Trusses
This is also a type of steel trusse which are usually used in large industrial buildings with short-span roofs. It is the oldest and strongest type of steel truss. These steel trusses would be attached to large beams and allow enough natural light to enter the interior.
The trusses are fitted with glass on the steep or short side to allow for light transmission and reduce carbon emissions. In addition, the steel trusses have good airflow, robust construction, and wide spans of 20 to 30 meters, making them ideal for use on industrial shop roofs. To limit excessive solar heat, the glazing surface should face north or northeast.
Areas of application:
For roofs of large industrial buildings with short spans.
Saw-Tooth Steel Truss
The saw-tooth steel truss is a type of steel truss for the top of multi-span buildings. This type of steel truss is similar to North-light steel trusses in that the repeating portion of the truss forms a ridge, giving the roof a zigzag shape.
The shorter side of each steel truss is covered with glass and turned back to the sun. This brings in enough natural light while avoiding direct sunlight that could heat up the building. In addition, the shiny sides form a line pattern.
Areas of application:
Saw-tooth steel trusses are ideal for large industrial buildings with multiple sections. They help provide even natural light and can reduce the heat from sunlight.
Warren Steel Truss
Named after its creator, James Warren, the Warren steel truss is a sturdy load-bearing structure. It consists of longitudinal members with a series of equal and alternating members that form an equilateral triangle.
Warren steel truss is supported by bars of the same length and can withstand pushing and pulling forces very well. Thus, these steel trusses help in spreading the weight evenly across the sections. They are not meant to provide a specific or stabilizing load to the support.
Warren steel truss is strong, lightweight, and easy to install. Hence, it is one of the most popular steel trusses for various construction projects.
Areas of application:
- Warren steel truss is the best support structure when building modular steel railroad bridges.
- Warren steel truss is suitable for commercial buildings with roof spans ranging from 20 meters to 100 meters.
- This steel truss also helps in the construction of gantry cranes or beam cranes.
Howe Steel Truss
Howe steel truss can be made of wood, steel, or a combination of both materials. This truss was created by Willian Howe in 1840 and is famous for building railroad bridges.
The Howe steel truss is constructed in a manner similar to the inverted Pratt steel truss, which uses straight circular steel columns to connect the top and bottom beams. Diagonal members then connect the bottom of one column to the top of the next.
Howe steel trusses typically span between 7.3 and 18.3 meters. Depending on the design and project requirements, the maximum length can be 30 meters or longer.
Areas of application:
- The Howe steel truss is an excellent choice for the construction of train bridges. This is because it can withstand weight very well, especially in the lower part.
- It can also be used to build roof structures to support various loads that exert pressure on the upper trusses. For example live loads, dead loads, or moving loads.
King Post Steel Truss
King Post truss is another type of steel truss that is used to support buildings with huge roofs. Moreover, it is suitable for short-span roofs from 5 to 10 meters, making it ideal for smaller houses.
The main vertical component known as the “king post” connects the lower chord to the intersection of the two upper chords. At the base of the main columns, the columns are connected to the opposite sides of the roof beams to form a lattice truss. In addition, the vertical columns prevent the connecting beams or the lower part of the structure from bending in the middle.
Areas of application:
- King Post steel truss is a short-span roof support structure. It gives a stylish look to the roof of a building.
- In aviation, this steel truss is used to provide strong support for airplane wings.
- If your project includes the construction of short-span bridges, then the King Post steel truss is a good choice.
Queen Post Steel Trusses
While the Queen Post steel truss has two vertical support columns, the King Post steel truss has only one support column. Therefore, unlike a truss with one center post, it does not put more weight on the middle of the connecting beam.
In addition, each symmetrical queen post is connected to the diagonal edges of the two inclined top beams. The two queen posts prevent the horizontal or connecting beams from yielding. With the extra support columns, the truss can achieve longer spans than the King Post truss.
In addition, to ensure the stability of the two columns, their upper ends are connected by a tension beam. The Queen Post steel truss is versatile, easy to design, lightweight, and adds beauty to roof designs. With spans of typically 8 to 12 feet, it’s perfect for small buildings or shade structures. In addition, you can customize it to meet your roofing or architectural needs.
Areas of application:
Queen Post steel truss can be used to build roof structures or porch bridges.
Flat Steel Truss
Another truss type in the list of steel truss types is the Flat steel truss. This truss is simple and cost-effective. It consists of two parallel lower and upper beams connected by diagonal steel members.
The dead or live loads applied to the top chord are distributed through the connected members and finally reach the two lower support points. In addition, you can build Flat steel trusses according to your own architectural requirements.
Areas of application:
- Flat steel trusses are usually suitable for the construction of flat roof structures in buildings with restricted heights.
- This steel truss is also suitable when the building project requires a support structure for the floor or slab.
Scissors Steel Truss
The scissor steel truss is also a truss structure. It has inclined stringers at the bottom which cross in the center to form a “V” shape at the bottom and an “X” shape at the top. The stringers then cross to form the scissors shape.
Scissors steel trusses have large spans of up to 50 meters. This depends on the specification of the steel and the height of the roof. It is more expensive to make compared to other types of steel trusses such as King Post or Queen Post.
If you need extra space or just want a higher roof for your building. Then the Scissors steel truss is the ideal solution!
Areas of application:
- You can consider Scissors steel truss for residential or commercial buildings with raised ceilings.
- It is also ideal for shading at commercial events.
Steel Fan Truss
Another type of steel truss that can be used in commercial buildings is the fan truss. it looks very similar to the Fink steel truss. It has extra steel webs on the top chord to allow it to carry more weight. Depending on your building requirements, the steel fan truss can cover spans from 10 to 40 meters.
Areas of application:
Steel fan truss is suitable for roof structures of large residential or commercial buildings.
Attic Roof Truss
If you need to build a storage room on the roof of your building, consider the attic roof truss. the upper part of this steel truss looks like the royal column steel truss. but its design is more complex as it includes a roof area.
Areas of application:
If your project requires additional storage in the ceiling or additional space in a room. Then you can consider using an attic roof truss.
Conclusion
Choose the steel truss type according to the project requirements. You should keep the following points in mind before the project engineer sets the criteria:
- Estimated weight or force on the roof or structure
- Roof design, form, and length
- Required ceiling height
- Architectural requirements
- Selection of quality steel
