When it comes to foundations, there are many options to choose from. Screw piles are one of the most popular choices for engineers and builders due to their cost effectiveness and the green benefits that come with them.
They are a deep foundation system that can be installed at a much lower depth than most other foundation systems. This is especially helpful for contaminated soil sites, where other methods may not be suitable. You can purchase some good quality screw piles from Screw Pile Pros.
The Lead
An In-Depth Look at How Screw Pile Foundations Work
Screw piles are a patented deep foundation system that is fast and easy to install. They are also a highly versatile solution for ground improvement projects and offer many advantages over conventional concrete foundations.
Unlike driven piles, screw piles do not require concrete to harden or grout to dissipate pore water pressures. This makes them the ideal choice for foundations that must be load-bearing immediately after installation.
The lead section, which possesses a tapered pilot point and one or more bearing plates, is the first part of the pile to penetrate the ground. It can be constructed in various lengths and thicknesses to suit the project’s specific requirements, ranging from 1.2 to 4 metres.
This lead section is usually drilled, not driven, to a specified depth calculated for the required boardwalk load capacity. It is then installed using a variety of earthmoving equipment fitted with rotary hydraulic attachments. These range from skid-steer loaders to 5 tonne through 80 tonne excavators.
Correct installation techniques are essential to meet engineered design load and settlement outcomes, and they need to be monitored during the IDEAL process using a torque measuring device as each helical pile is being installed. Having a third party engineer to supervise the installation can further increase confidence in pile performance.
Another major advantage of screw piles is that they are installed with minimal soil disturbance, which means that a reduced disturbance area can be achieved. This is especially beneficial for projects where soil conditions are less than optimal or where it is difficult to remove the existing structure while screw piles are being installed.
Screw piles can also be installed in a wide range of soils, which can make them an excellent solution for projects in contaminated sites or where the ground is too unstable to support other deep foundation options. They are also able to be installed in all weathers, and don’t require time to settle down or dry, which can help with projects requiring temporary foundations.
Screw piles are a good option for deep foundations that need to be installed quickly, and they can be fabricated in sections, making them a modular construction method. This can help to reduce the overall cost of a project and ensure that the foundations are ready to load when needed.
The Extensions
Screw piles are a type of deep foundation system that has been around since the early 1900s. They are used for a variety of purposes, including supporting structures in poor soil conditions and increasing the capacity of existing structures.
They have been shown to be more resistant to earthquakes than poured concrete foundations because they are not subject to soil liquefaction (soil behaves like a liquid and can change stress conditions, as seen in an earthquake), which affects concrete foundations. Additionally, they are not subject to shifting due to soil compaction or poor soil preparation as concrete foundations are.
In addition to their earthquake resistance, screw piles are also great for projects that require high-pressure foundations, such as power lines or bridges. They can withstand a much greater pressure than a concrete foundation, and they don’t need to be poured or cured.
Another great feature of screw piles is their versatility – they can be extended in multiple ways, which makes them ideal for a number of different applications. For example, if a project requires more load-bearing capacity than originally intended, the engineer can simply add an extension section to the pile to increase the capacity.
This process of extending the piles and changing the configuration of the helical elements is a unique feature of screw piles, which can save both time and money on the project. In addition, the ability to add extensions helps to ensure the proper bearing capacity of the screw piles.
Because of their versatility, screw piles are well suited for projects that involve retrofitting, restoration and other situations where there may not be sufficient headroom or access to construction equipment. They are also very efficient at sites where contaminated soils may be encountered.
Unlike traditional foundations, which tend to be more shallow, screw piles are much deeper and have greater capacity to withstand lateral forces, like wind. This is especially important for top-heavy structures, such as solar panels or wind turbines, that are exposed to high winds.
The Shaft
The shaft is the piece of the screw pile foundation that first penetrates the ground and transfers load. It can consist of a lead, which contains multiple helical bearing plates, or a plain extension, depending on the torque needed and the depth of the soil.
Unlike driven piles or drilled shafts, the true helix geometry of the steel bearing plates discourages soil disturbance during installation. This makes it easier for the pile to penetrate the soil and transfer the required torque.
In addition, the shaft can be rotated into the ground at any angle. This allows for a large range of penetration depths without having to dig deep trenches.
The shaft can also be installed in a variety of subsurface conditions, from soft to stiff clays and loose to dense sands. This allows for a wide range of design loads, from less than 1kN (225 lb) to over 5,000kN (1.125 million lb) depending on the needs of the project.
It can be loaded immediately after installation, eliminating the need for concrete or grout to harden, and allowing for any excess pore water pressures to dissipate quickly. This can be important in a project where the construction schedule is tight.
As a result, it is possible to get screw piles installed in shallower areas that require deeper excavations for other foundations. This can speed up construction and reduce costs as a result.
Additionally, it can be installed in restricted access areas where digging would be difficult and potentially dangerous. This is especially useful in areas with trees or other obstacles that could cause damage to the installation if not contained.
Another benefit of the screw pile foundation is that it can be installed in a small work footprint, compared to other types of installation. This can save time and money on a project by not having to waste valuable time removing soil cuttings or other debris from the site after installation.
The screw pile foundation is one of the most effective deep foundation solutions available for a wide range of projects. This is because it can restrain axial and uplift loads, as well as lateral forces.
The Bracket
A bracket or load transfer device (LTD) is one of the most important components of a screw pile foundation. It helps to transfer the weight of the existing structure from unstable soils to competent soil or bedrock, and it is used in many different applications.
The bracket is a critical part of how screw pile foundations work, and it can be one of the most challenging aspects to understand. However, if you understand how it works, you’ll have an easier time understanding how the other parts of the screw pile foundation work as well.
In simple terms, the bracket is a piece of steel that connects to the top of a screw pile. It also allows for the pile to be threaded into the ground, which minimizes installation time and reduces the amount of soil disturbance that must take place.
Brackets are available in a variety of different sizes and shapes, depending on the needs of each project. Some are designed to be used for residential buildings or small commercial structures, while others are specialized for industrial and heavy duty projects.
Most brackets are rated for 50 ksi or less, but heavier-duty ones may be needed to handle larger structures. There are also special brackets, such as helical mooring caps, that are specialized for specific types of float docks or moorings.
Once a screw pile is installed, the bracket attaches to it, and the structure’s weight is transferred to the anchor that is attached to the bottom of the bracket. This transfers the structure’s weight from incompetent soils to competent soils or bedrock, which then holds the structure securely in place.
Because of their flexibility and ease of installation, screw piles are an excellent deep foundation solution for a variety of different structures. They can be used to stabilize sinking or settling foundations, and they can even be installed in areas where conventional concrete foundations aren’t possible. They’re also highly cost-effective compared to other deep foundation alternatives. They can also be installed quickly, allowing for load transfer to occur as soon as the pile is installed.