How to choose screw piles correctly?

For any construction project, selecting the proper screw piles is essential to guarantee stability and longevity. Because they are simple to install and strong enough to support large loads, screw piles are frequently used in construction. They are particularly well-liked for projects in regions with difficult soil conditions that call for deep foundations.

The type of soil should be taken into account first when choosing screw piles. To guarantee adequate anchorage and load-bearing capacity, different kinds of screw piles are needed depending on the composition of the soil. For example, non-cohesive soils like sand may require longer piles to reach stable layers, while cohesive soils like clay may require piles with larger helix diameters to provide adequate stability.

Expected load bearing capacity of the piles is another important consideration. The screw piles’ dimensions and design should be in line with the expected loads from the structure they will support. This load-bearing capacity is determined by engineers using a variety of factors, including the building’s weight, the surrounding conditions, and any additional loads like wind or snow.

Compatibility of equipment and installation technique are also essential factors. Screw piles can be installed in a number of ways, such as with manual torque equipment or hydraulic machinery. The approach selected should fit the project’s scope, schedule, and available equipment. In addition to preventing delays, ensuring compatibility with the installation equipment guarantees that the piles are installed correctly to the necessary torque and depth specifications.

Finally, take into account the screw piles’ resistance to corrosion. Corrosion can have a major effect on the piles’ lifespan and performance, depending on the site of the project and the soil. Selecting piles with protective coatings or made of galvanized steel can reduce the chance of corrosion and increase the foundation’s lifespan.

The rules for choosing for the foundation

When it comes to design and enhanced features, rifle piles are a different kind of support than traditional pillars.

These piles are made up of two components:

• barrel – a hollow metal pipe with a circular cross-section of a certain diameter;
• blades – the lower helical part with a larger diameter than the barrel.

The metal support is manually or mechanically screwed into the ground until the tip rests on hard rock, made possible by the screw blades. In addition, this design element gives the foundation a higher bearing capacity than pillars of the same diameter would.

Screw pile manufacturers currently provide a range of models with different geometric and structural features.

During the design phase, a comprehensive set of information, including the physical and chemical characteristics of the soil, must be considered when selecting supporting elements in an appropriate configuration.

What to pay attention to first?

The manufacturer’s catalog has a surprising variety of screw piles that will surprise an inexperienced builder. As a result, you must choose in advance what qualities the future foundation should possess. Standards by which piles vary:

1. steel grade. The parameter is selected based on the required rigidity and strength of the foundation in relation to the geological features of the site, as well as operating conditions.
2. Wall thickness and barrel diameter. The higher the content of chemically aggressive substances in the soil, the more stringent the requirements for the strength of supports. By choosing piles with thin walls, the developer risks reducing the service life of the foundation several times.
3. Blade diameter. The size of the helical blades depends on the expected load that the future structure will exert on the ground, and, in turn, on the bearing capacity of the soil masses.
4. Barrel length. The parameter is selected after calculating the soil freezing depth. As a rule, the pile is lowered below the freezing point.
5. Blade configuration. Specific models have been developed for each type of soil. A wide range of screw piles allows you to select an element for soils that differ in porosity, humidity, granulometric composition, etc.d.

How thick should the walls of the elements be??

Choose the metal’s thickness based on the site’s known corrosive activity of the soil.

Experts advise determining the building’s design durability and confirming that the residual metal thickness complies with the design loads in line with GOST 27751-2014 in order to ensure that the parameters are selected correctly.

Diameter

The following ratio of the trunk diameter to the blade diameter (mm) characterizes the elements’ standard parameters:

• 32/100;
• 42/150;
• 48/150;
• 57/200;
• 76/200;
• 89/250;
• 102/250;
• 108/300;
• 114/300;
• 133/350;
• 159/350;
• 168/500;
• 219/500;
• 325/850.

It is feasible to produce supports with a non-standard configuration if needed. Pile diameters of 89 mm are adequate for planning the construction of a private house (wooden, frame, panel, foam concrete) with one or two stories.

108 mm cross-sectional diameter structures are used for large buildings up to 3.5 tons in weight. In this instance, the foundation’s rigidity and strength requirements in relation to soil corrosion processes also influence the pile diameter selection.

Tip type

The way the tips are connected to the pipe is what primarily distinguishes them from one another:

1. Welded ends that are welded to the pipe.
2. Cast – are a continuation of the barrel body.

When building industrial structures where higher soil loads are anticipated, cast-tip piles are employed.

It makes no sense to overpay for cast structures when designing private homes and lightweight constructions, as supports with welded tips will supply the required load-bearing capacity.

The tips’ shapes also differ:

• round;
• cruciform;
• pointed;
• cut at an angle.

Here, the decision is dependent on both the soil’s density and the existence of solid inclusions (stones, metal debris, etc.) in the soil. The easier it is for the pile to overcome soil resistance, the sharper the tip.

Protective covering

When in operation, metal on metal contact with the ground can cause corrosion in piles. Moisture has a greater influence on the portion of the pipe that is in contact with the soil and atmosphere. A layer of protection is put on top of the pile to mitigate the damaging effects of the outside world.

Coating types:

• polyurethane;
• zinc;
• epoxy;
• polymer;
• enamel, etc.d.

When buying a pile, it’s crucial to consider the protective coating’s quality because the metal will be subjected to abrasive action from the soil during the installation process.

There should not be any scratches on the metal when you run a coin or key over the pipe’s surface, nor should the steel be visible. If not, the product is not worth purchasing because of the poor quality of the coating.

The developer can apply a primer or mastic to the metal to prevent rust if he doesn’t want to overspend or doesn’t trust the integrity of the protective layer.

What affects the cost?

A novice builder will find it challenging to select piles with the appropriate modification from the full range of comparable designs.

In these kinds of situations, buyers are typically guided by the product’s price.

It’s important to comprehend the cost considerations prior to placing the foundation’s screw pile order.

The following factors affect the final cost:

1. Metal quality. Unscrupulous manufacturers save on the quality of steel in order to reduce the cost of their goods. In fact, the ability of the foundation to withstand loads both from the structure and from ground movements directly depends on this parameter.
2. Metal thickness. The thinner the pipe wall, the cheaper the product. Moreover, there is a direct relationship between this parameter and the strength of the supports.
3. Pipe diameter. As in the case of metal thickness, the choice is based on the required strength characteristics of the base.
4. Coating quality. Susceptibility to corrosion processes is the main disadvantage of metal poles. Therefore, it is advisable for the owner to provide protection from the effects of humidity at the stage of purchasing building materials.

It’s important to take into account a number of important factors when choosing screw piles for construction projects in order to make the best decision. Numerous factors come into play, including the type of soil, load-bearing capacities, environmental factors, and installation techniques. It is easier to choose the right screw pile design, size, and material composition when these factors are understood. Builders can minimize expenses and environmental impact while optimizing structural stability, longevity, and overall project success by making well-informed decisions grounded in these factors. This article examines these crucial factors to help you make an informed decision when selecting screw piles for building and maintenance projects.

Useful video

More details regarding the video’s selection of piles:

For stability and durability in your construction project, selecting the appropriate screw piles is essential. Compared to conventional concrete foundations, screw piles have a number of benefits, such as quicker installation times, less excavation, and a smaller environmental footprint. These are important things to think about when choosing screw piles.

First, evaluate the state of the soil at the construction site. Different kinds of screw piles are needed for different kinds of soil. For instance, in order to provide enough bearing capacity, piles made of clay or other cohesive soils may require larger helical blades. On the other hand, longer shaft piles might be necessary to reach a stable stratum in non-cohesive soils like sand.

Second, think about your structure’s load-bearing needs. The anticipated loads from the building or structure should be taken into consideration when selecting the screw piles’ diameter and length. To ascertain the precise requirements required to sustain the weight and guarantee the stability of the foundation, engineering calculations are crucial.

Thirdly, assess the site’s environmental elements. The selection of screw piles can be influenced by variables like seismic activity, water table level, and frost depth. To withstand these environmental challenges and stop foundation movement over time, piles may need to be installed deeper or with more reinforcement.

Consider the installation procedure and accessibility as well. Because they are simple to install in confined spaces and remote areas, screw piles are frequently chosen. Verify that there won’t be any logistical difficulties in delivering and installing the selected screw piles using the equipment at hand.

Finally, think about the requirements for long-term maintenance. Despite their reputation for longevity, screw piles may still require routine maintenance and inspection, particularly in areas with corrosive soil. Selecting premium materials and coatings helps reduce maintenance requirements and increase pile longevity.

Selecting the appropriate screw piles for your construction project can guarantee a stable and dependable foundation by carefully taking into account various factors such as soil conditions, load-bearing requirements, environmental considerations, installation considerations, and maintenance needs.

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