In the world of modern steel construction, strong and efficient connections are just as important as the structural members themselves. One of the simplest yet most essential components used to achieve secure and versatile joints in steel frameworks is the steel cleat. Often referred to as part of a broader cleat steel system, steel cleats offer engineers, fabricators, and builders a reliable way to join beams, columns, and other steel sections. In this article, we explore what steel cleats are, how they are used, their types, and why they play such a critical role in structural design.
What is a Steel Cleat?
A steel cleat is a small steel plate—either flat or angle-shaped—used to connect different members in a steel structure. These cleats are typically welded or bolted onto a primary member (such as a column or girder) and then bolted to a secondary member (like a beam or purlin). The use of cleats allows for quick, secure, and often modular connections that make erection faster and more efficient.
Cleat steel systems rely on these plates as the interface between components, particularly when dealing with hollow sections like SHS (Square Hollow Section) or RHS (Rectangular Hollow Section) members, where through-bolting may be impractical or impossible.
The Role of Steel Cleats in Structural Steelwork
The primary function of steel cleats is to facilitate connections. Whether in high-rise buildings, bridges, warehouses, or residential steel frames, cleats help align and secure steel members, transferring loads between them safely and efficiently.
Key Advantages:
Speed of Installation: Cleats are often pre-welded to structural members in the fabrication shop. Once on-site, beams can be quickly bolted into place, minimizing welding time.
Design Flexibility: They can accommodate a range of member sizes and angles, making them highly adaptable.
Modularity: In prefabricated or modular steel construction, cleats standardize connections and simplify assembly.
Cost-Efficiency: By reducing on-site labor and enabling repeatable connections, cleats help lower overall construction costs.
Types of Steel Cleats
There are several types of steel cleats, each suited for different applications:
1. Angle Cleats
These are L-shaped steel plates that are commonly used to connect beams to columns. One leg of the angle is attached to the supporting member (typically via welding), while the other leg is bolted to the incoming member.
2. Flat Cleats
Flat plates used in connections where both members meet at right angles. These are often bolted to both members and used in lighter structures or where aesthetics matter.
3. End Plate Cleats
Used in moment-resisting frames, end plate cleats can be designed to resist bending moments as well as shear, and are typically thicker than angle cleats.
4. Web Cleats
These are positioned on the web of a beam or column and used primarily in web-to-web or web-to-flange connections.
Common Applications of Cleat Steel Connections
Cleat steel systems are used across a wide variety of projects:
– Industrial Buildings
Large warehouses and factories often rely on steel cleats to connect purlins and girders quickly and safely. In portal frame construction, cleats play a major role in joining rafters to columns and cross bracing systems.
– Multi-Storey Buildings
In high-rise construction, cleats are used to attach floor beams to main steel columns. Their precision and load-bearing capacity make them ideal for buildings with repetitive framing.
– Modular Construction
Prefabricated steel buildings and container-style homes utilize cleats to speed up on-site assembly. They ensure accuracy in alignment and make components interchangeable.
– Bracing Systems
In seismic or wind-resistant designs, cleats connect bracing members to frames, helping transfer lateral forces safely through the structure.
Design Considerations When Using Steel Cleats
Designing with steel cleats involves both engineering and practical considerations. Here are a few critical factors:
Bolt Configuration: Number, size, and grade of bolts must be appropriate for the loads being transferred.
Weld Size and Type: If cleats are welded, the welds must meet strength and code requirements.
Thickness of Plate: Depending on load and moment, cleats may need to be thicker or stiffened.
Hole Positioning: Proper edge distances and spacing are vital to avoid tear-out and ensure full load transfer.
Codes and standards such as AISC, Eurocode, and Australian Standards (AS 4100) offer detailed guidance on cleated connections.
Fabrication and Installation Benefits
One of the biggest advantages of using steel cleats is the efficiency they bring to fabrication and erection. Cleats can be fabricated off-site under controlled conditions, reducing on-site complexity. With bolt holes pre-drilled and cleats welded in position, connecting members becomes a quick process with minimal alignment issues.
On large projects, this modularity ensures consistency across the site. Crews can install dozens or hundreds of identical connections without having to measure and cut in the field. This not only saves time but improves safety by minimizing high-risk welding at height.
Sustainability and Reusability
In an era where sustainability is becoming increasingly important, cleat steel systems provide an edge. Since cleated connections can often be unbolted rather than cut or demolished, they allow for the reuse of structural components. This is especially beneficial in temporary structures or buildings designed for future expansion or relocation.
Furthermore, the simplicity and standardization of cleated joints reduce material waste during fabrication, aligning well with green building principles.
Conclusion
Steel cleats are a small but vital part of the larger cleat steel ecosystem. They offer practical, reliable, and economical solutions for connecting steel members across various types of structures. Whether in heavy industrial construction or elegant architectural steelwork, the use of steel cleats brings speed, strength, and simplicity to every joint.
By understanding their functions, design requirements, and advantages, engineers and builders can fully leverage these components to improve both structural performance and construction efficiency. In short, when it comes to building smarter with steel, cleats are one detail that should never be overlooked.
