In construction, specifically within excavation work, a strut is a support element used to stabilize vertical walls.
Understanding Struts in Excavations
Struts are essential supports in civil engineering and construction, particularly when dealing with deep or unstable excavations. As the provided reference states:
Struts are supports, generally made of steel or concrete but sometimes also of timber, which are used to retain the walls of a vertical excavation. They are installed inside the excavation as the earthworks progress and generally support each side of the excavation.
This means that struts act as horizontal bracing members installed across an excavation pit to prevent the retaining walls (like sheet piles or soldier piles and lagging) from collapsing inwards under the pressure of the surrounding soil.
Key Characteristics
Based on the definition, here are the main aspects of struts in excavation support:
- Purpose: To retain the walls of a vertical excavation, preventing instability and collapse.
- Function: They provide support by bracing across the excavation.
- Materials: Commonly steel or concrete, though timber is also used.
- Installation: Placed inside the excavation incrementally as earthworks progress.
- Placement: Typically connect and support each side of the excavation.
Materials Commonly Used for Struts
| Material | Common Use Cases | Advantages |
|---|---|---|
| Steel | Large, deep excavations | High strength, reusable, adaptable lengths |
| Concrete | Permanent support structures | Durability, can be integrated into final build |
| Timber | Smaller, temporary excavations | Cost-effective, easy to cut and adjust |
These materials are chosen based on the required strength, duration of support, and site conditions. Steel struts, often hydraulic or fabricated from universal beams, are highly versatile for temporary support systems in urban or complex environments.
Practical Application
Imagine digging a deep trench or basement. Without support, the soil on the sides would cave in. Retaining walls are installed, but they also need bracing to resist the immense lateral pressure. Struts are installed horizontally between these walls, pushing against them to maintain the excavation's shape and ensure safety for workers and surrounding structures. They are typically part of a larger bracing system that might also include walers (horizontal beams running along the retaining walls) and sometimes rakers (diagonal supports).
In summary, a strut in this construction context is a crucial horizontal bracing element that provides necessary support to the walls of an excavation, using materials like steel, concrete, or timber, installed progressively during digging.
