Why choose lightweight shoring
Listed below are the four core attributes that typically influence the decision to choose a lightweight shoring solution:
- Swift mobilisation
- Simple assembly
- Fast installation
- Can be manually handled
Lightweight shoring is suitable for short term projects involving minor excavations and general repairs to infrastructure. The above four attributes make this type shoring the obvious choice when dealing with situations demanding a rapid and prompt response. In addition to emergency use, utility providers supplying water, gas and electricity services will often choose a lightweight system for small or extended trench runs when installing pipework or cables. Lightweight systems are often used by rail networks who have to operate within a restricted working area and a limited timeframe.
A choice of lightweight materials
Where lightweight shoring is deemed to be the most effective solution, the type of material must also be determined. Generally, the most common materials found in lightweight trenched shoring are wood, plastic and aluminium.
Timber shoring generally consists of cross-bracing which is customised to fit the excavation, however any advantage of using timber can be easily outweighed by its fixed, non-adjustable nature. The initial manufacture or subsequent modification of the structure during temporary works requires a skilled joiner and could also introduce the inherent dangers of having to work in an unsupported or partially supported trench.
Aluminium lightweight shoring provides full active support to the pressures acting on the panels and aluminium panelled systems can be utilised for extended periods as the walls of the excavation remain fully supported for the entire life of the project.
The modular design of aluminium box systems means two, three or four sided configurations are possible and the strength of the material means boxes can typically be stacked higher, enabling contractors to reach much greater depths. This, together with ease of manual assembly outside of the excavation makes aluminium systems very versatile.
As well as transport, assembly, handling and installation considerations, the decision to choose a particular system or material will also involve more complex factors such as ground pressure and Safe Working Load (SWL). Below is a brief example showing a single step in the decision making process when producing a temporary works design.
In this case, aluminium is compared with plastic:
The typical aluminium box SWL ranges from 68.5kN/m2 compared to the plastic equivalent of 16.5kN/m2. It is also worth noting that aluminium trench box systems are designed to work with minimum ground surcharges of 10 kN/m2 only, in accordance with industry standard shoring design guidelines; the equivalent plastic system considers a maximum ground surcharge of 5 kN/m2.
Groundforce offer a range of lightweight shoring products
Lightweight shoring typically comprises modular aluminium systems such as hydraulic braces, vertical shores , trench boxes and inflatable solutions. Each system is specifically designed to perform a certain task in a given scenario, but what all lightweight shoring products have in common is the ability to facilitate fast, manageable solutions for smaller projects such as those found in the utilities and rail sectors when undertaking short-term or emergency projects.
All Groundforce’s lightweight shoring product range is supported by a full design and advisory service. Further technical product information is available in the Technical File
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