Construction Strut: Definition, Types, Applications, and Importance
Introduction
In the world of building and civil engineering, maintaining the structural integrity of a framework is of utmost importance. One of the key components that ensures this integrity is a construction strut. Whether it’s a deep excavation, a bridge truss, or a concrete formwork system, the strut plays a silent yet powerful role in maintaining stability and safety.
But what exactly is a construction strut? Why is it used? What materials are suitable for it? And how do you choose the right type of strut for your construction project?
In this detailed article, we’ll answer all these questions and more. You’ll learn about the different types of struts, their functions, installation techniques, and applications across construction projects.
What is a Construction Strut?
A construction strut is a compression member used in building and civil projects to resist axial loads and prevent buckling or collapse of structural elements. These members are designed to transfer loads from one point to another while maintaining the geometry and alignment of the system.
Struts are especially useful in temporary supports, truss systems, formwork bracing, and excavation support structures. They can be made from timber, steel, aluminum, or even reinforced concrete, depending on the application and load requirements.
Purpose of Struts in Construction
Struts serve several crucial functions in construction:
- Distribute Loads: They help transfer compressive loads evenly to other structural components.
- Prevent Collapse: In excavation or temporary formwork, struts prevent the collapse of soil or formwork walls.
- Maintain Spacing: Struts hold structural members in place and ensure accurate spacing in trusses and frameworks.
- Enhance Rigidity: They contribute to the overall stiffness of the structure, reducing the risk of deformation.
Common Types of Construction Struts
Different types of struts are selected based on their orientation, load direction, and application. Below are the most commonly used struts in construction:
1. Horizontal Struts
- Placed horizontally between two surfaces or walls.
- Commonly used in excavation pits and trench shoring systems.
2. Raking Struts
- Inclined struts that transfer load diagonally from a vertical surface to the ground.
- Used in shoring systems for temporary wall support.
3. Flying Struts
- Span across a trench or gap without intermediate support.
- Ideal for tight spaces where ground access is limited.
4. Vertical Struts
- Provide vertical support under beams or horizontal structures.
- Often used in formwork systems and scaffolding towers.
Materials Used for Construction Struts
Each material used for strutting comes with its advantages and limitations. Choosing the right one depends on load-bearing capacity, environment, cost, and reusability.
| Material | Best For | Pros | Cons |
|---|---|---|---|
| Timber | Light formwork, shallow trenches | Easy to cut, cost-effective | Susceptible to decay, not reusable |
| Steel | Heavy load-bearing applications | Durable, high strength, reusable | Heavy, needs rust protection |
| Aluminum | Lightweight formwork, scaffolding | Corrosion-resistant, lightweight | Less strength than steel |
| Concrete | Permanent structural struts | Long-lasting, fire-resistant | Very heavy, not suitable for temporary use |
Applications of Construction Struts
Construction struts are indispensable in various construction phases. Let’s look at some of the primary areas where struts are used:
1. Trench and Excavation Support
- Struts prevent lateral earth pressure from collapsing trench walls.
- Used with walers and sheeting in trench shoring systems.
2. Concrete Formwork Bracing
- Provide support to retain the shape of the formwork during pouring and curing.
- Prevent shifting due to the pressure of wet concrete.
3. Structural Trusses
- In permanent structures like bridges or roofs, struts are integral to triangular truss designs.
- Help distribute and manage compressive loads.
4. Shoring and Temporary Support
- Raking and flying struts are used to brace walls during demolition or façade retention.
- Prevent structural failures during alterations.
5. Scaffolding Systems
- Vertical and diagonal struts reinforce load-bearing capacity of scaffold towers.
How Are Construction Struts Installed?
Installing struts correctly is vital to ensure their performance and safety.
Step-by-Step Installation:
- Site Preparation
- Clean and level the ground.
- Place base plates or walers to distribute load.
- Positioning
- Measure and position struts according to engineering drawings.
- Use appropriate angles for diagonal or raking struts.
- Fixing
- Secure struts using mechanical jacks, wedges, or fasteners.
- Ensure tight connections to prevent displacement.
- Load Testing (if required)
- For high-risk projects, perform load testing to verify strength.
- Regular Inspection
- Inspect regularly for deflection, rust, or damage, especially in temporary struts.
Benefits of Using Struts in Construction
- Enhances Safety: Minimizes risk of structural collapse during construction.
- Improves Load Management: Distributes loads effectively in complex structures.
- Reduces Material Movement: Keeps framework or excavation walls firmly in place.
- Cost-effective (when reusable): Steel or aluminum struts can be reused across multiple projects.
- Versatile Application: Suitable for both temporary and permanent structural needs.
Limitations and Challenges
Despite their usefulness, struts come with a few limitations:
- Can obstruct workspace, especially in tight excavation zones.
- Improper installation can lead to catastrophic failures.
- Timber struts are not suitable for prolonged or humid exposure.
- Steel struts require maintenance to avoid corrosion.
- They may increase project complexity if not pre-engineered.
Best Practices for Construction Struts
- Always consult a qualified engineer for design and spacing.
- Match strut material with project demands.
- Use anti-corrosive coatings for steel in wet conditions.
- Inspect periodically for any signs of stress, deformation, or misalignment.
- Document installation procedures for safety compliance and future audits.
Conclusion
The construction strut may seem like a basic component, but it performs an essential role in maintaining the safety, stability, and effectiveness of any structural system. Whether it’s keeping a trench from collapsing, bracing a façade during renovation, or strengthening a roof truss — struts are foundational to modern construction practices.
Their design, material selection, and proper installation must never be underestimated. With the right approach and engineering supervision, struts can significantly reduce risk, increase efficiency, and deliver long-term structural success.
Frequently Asked Questions (FAQs)
Q1. What is a construction strut used for?
A construction strut is used to resist compressive forces and support frameworks, formworks, excavations, or permanent structures by distributing loads and preventing structural failure.
Q2. Are struts only used in temporary structures?
No. While struts are commonly used in temporary supports, they are also a key part of permanent trusses, bridges, and roof systems.
Q3. Can wooden struts be used in deep excavations?
Wooden struts are typically limited to shallow or light-load applications. Deep excavations usually require steel or aluminum struts due to higher strength and durability.
Q4. What is the difference between a strut and a beam?
A beam primarily resists bending, whereas a strut resists axial compression. They serve different structural purposes.
Q5. What is a flying strut?
A flying strut spans across an opening without resting on the ground. It is commonly used in urban areas where ground space is limited, such as façade retention during renovations.
Q6. Do struts require regular maintenance?
Yes, especially steel struts, which can corrode over time. Regular inspection and maintenance ensure the strut remains safe and functional throughout the construction cycle.
