Strut in Construction: Purpose, Types, and Applications
Introduction: The Essential Role of Struts in Construction
In the complex world of construction engineering, structural stability is a cornerstone of safe and successful projects. Whether constructing a skyscraper, trenching a pipeline, or bracing a temporary wall, one element consistently proves vital: the strut.
A strut in construction refers to a structural component designed to resist axial compression. It serves as a key load-transferring element that maintains the integrity and alignment of structures. Struts are widely used in temporary frameworks, excavation support systems, formwork, trusses, and permanent buildings.
This comprehensive guide will help you understand the function, types, materials, and real-world applications of struts, along with installation practices, benefits, limitations, and best usage tips.
What Is a Strut in Construction?
A strut is a compression member designed to withstand axial forces, typically positioned to resist buckling or deformation caused by external loads. In construction, struts are used to:
- Provide lateral or vertical support.
- Transfer loads to stable points.
- Maintain alignment during assembly or excavation.
- Brace formwork during concrete pouring.
Struts can be temporary (used during excavation or formwork) or permanent (integrated into trusses, bridges, or towers).
Key Functions of a Strut
- Transfers loads from one part of a structure to another.
- Resists axial compression to prevent buckling.
- Supports trenches to avoid soil collapse.
- Braces frameworks during construction.
- Maintains spacing and alignment in trusses and formwork.
Types of Struts in Construction
Different types of struts are used depending on the purpose, load, and space constraints:
1. Horizontal Strut
- Positioned parallel to the ground.
- Used mainly in trench bracing systems.
- Connects opposite walls to resist soil pressure.
2. Inclined or Diagonal Strut
- Angled placement between two surfaces.
- Common in formwork systems and scaffolding.
- Transfers forces along an angled path.
3. Raking Strut
- Positioned at a steep angle (typically 45°–75°).
- Used in shoring systems to transfer loads to the ground.
- Offers strong support for temporary wall bracing.
4. Flying Strut
- Spans horizontally between walls without touching the ground.
- Ideal for urban excavation or where space is limited.
- Provides lateral support across wide spans.
Common Materials Used for Struts
Choosing the right material for a strut depends on load requirements, budget, project type, and whether it’s temporary or permanent.
| Material | Application | Advantages | Disadvantages |
|---|---|---|---|
| Timber | Light formwork, trenching | Lightweight, easy to handle | Prone to rot and termites |
| Steel | Heavy-duty structures | Strong, durable, reusable | Heavy, expensive, prone to rust |
| Aluminum | Scaffolding, light frames | Corrosion-resistant, lightweight | Lower strength vs. steel |
| Concrete | Permanent structures | Fire-resistant, robust | Heavy, non-reusable |
Applications of Struts in Construction Projects
1. Excavation and Trench Support
Struts help prevent soil collapse in deep excavations. They are usually installed with walers to brace the trench walls and ensure worker safety.
2. Trusses and Frameworks
In steel and wooden trusses, struts maintain spacing and help carry axial loads, ensuring the structure doesn’t buckle or sag.
3. Formwork Bracing
Struts hold formwork in place during concrete pouring, preventing deformation, movement, or collapse under pressure.
4. Scaffolding and Temporary Structures
Struts add stiffness and rigidity to temporary support systems such as scaffolding and staging.
5. Façade Retention and Restoration
Flying struts are used to brace historic façades during renovation or internal demolition, helping preserve the exterior shell.
Installation of Struts: A Step-by-Step Overview
Proper strut installation is essential for structural stability and worker safety.
1. Structural Assessment
- Analyze the load distribution, soil type, and dimensions.
- Design strut spacing and orientation with the help of a qualified engineer.
2. Surface Preparation
- Ensure the anchoring surfaces are firm and level.
- Place walers or plates to distribute load from the strut.
3. Fixing the Strut
- Install the strut between opposing walls or supports.
- Use turnbuckles, clamps, or mechanical jacks for fine adjustments.
4. Alignment Check
- Use levels and alignment tools to ensure the struts are straight and tight.
5. Inspection & Maintenance
- Perform regular checks, especially after concrete curing, rainfall, or mechanical shifts.
Advantages of Using Struts in Construction
- Improves structural safety by supporting compressive loads.
- Versatile use in temporary and permanent structures.
- Reusability of steel struts reduces long-term costs.
- Enhances worker safety in excavation and trenching.
- Reduces risk of structural deformation during concrete curing.
Limitations of Struts
- Occupy internal workspace, especially in narrow trenches.
- Require skilled installation to avoid collapse.
- Timber struts are vulnerable to weather and pests.
- Steel struts need anti-corrosion treatment in moist conditions.
- Improper spacing or fixing can lead to structural failure.
Best Practices for Using Struts Effectively
- Always engage a licensed engineer for load and spacing calculations.
- Choose materials based on project needs and site conditions.
- Use protective coatings on metal struts to prevent corrosion.
- Secure both ends of the strut to solid and reliable anchoring points.
- Follow local building codes and safety guidelines during installation.
Conclusion
A strut in construction is far more than just a support element—it’s a lifesaver in terms of structural stability, load distribution, and worker safety. Whether you’re stabilizing a trench, erecting a truss, or bracing formwork, the proper use of struts can dramatically enhance the durability and safety of your project.
From horizontal to raking, timber to steel, and temporary to permanent applications, struts are among the most versatile components in the construction world. Their correct selection, installation, and maintenance are crucial for ensuring optimal performance on-site.
Frequently Asked Questions (FAQs)
Q1. What is a strut in construction?
A strut is a structural member that resists axial compression and is used to transfer loads, maintain spacing, and support other components in construction frameworks.
Q2. How is a strut different from a brace?
A strut typically resists compressive loads, while a brace can resist both tension and compression depending on its placement and design.
Q3. Can struts be used permanently in a building?
Yes. Steel and concrete struts are commonly used in permanent structural frameworks, such as roof trusses and bridges.
Q4. Are wooden struts reliable for construction?
Yes, but only for temporary or light-duty applications. Timber is vulnerable to decay and termite damage, making it less suitable for permanent or load-heavy environments.
Q5. What are flying struts used for?
Flying struts are used when ground space is limited. They span between walls and are ideal for urban excavation projects or façade retention.
Q6. Who designs the strutting systems in a project?
Strutting systems should be designed by a qualified structural or civil engineer, who considers the load, material, and site-specific factors to ensure safety.
