Engineering and construction methods: Piling

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Piling is one of the most significant methods for civil engineering and construction infrastructure projects.

Piling is one of the most important aspects of the engineering and construction industry. Piling Professionals are high in demand and are critical in ensuring the stability, safety, and longevity of infrastructure projects. Without the knowledge and skills of piling engineers, structures would not have a reliable foundation and would be at risk of collapsing and causing property damage.

What is piling?

Piling is a deep foundation technique used to create solid and stable foundations for structures built on soft ground or soil in construction projects. This includes bridges, buildings, roads and highways, ports and harbours, and renewable energy. Piling foundations are long, cylindrical columns of timber, steel, and concrete drilled into the ground until they reach a stable layer of rock or soil. These columns, known as piles, transfer the structure’s load to the underlying rock or soil, providing a stable foundation.

Piling is a niche market due to its specialised nature, involving the installation of deep foundations for numerous structures. Moreover, the expertise and equipment required for piling in infrastructure projects make it a specialised field that requires skilled Pilling Professionals.

The significance of piling

Engineers have used piling for thousands of years, initially using timber and stone pile foundations to support structures. Today, Engineering and Construction professionals drive specialised equipment to drill piles into the ground.

The purpose of piling is to prevent the structure from settling or shifting over time due to the compressibility or instability of the soil. In some cases, piling is also used to support structures built on slopes or in areas prone to earthquakes or other natural disasters.

Overall, piling is an essential component of modern engineering and construction, enabling the safe and stable construction of buildings and infrastructure in a wide range of soil and ground conditions.

Click here to view the responsibilities of a Piling Engineer.

General Piling Process

The process of piling begins with a survey of the project site to determine the structure’s soil conditions and load requirements. Piles will then be designed to meet the needs and be spaced around the structure’s perimeter.

The piles are driven into the ground using specialised piling equipment. The process of driving the piles creates a hole in the ground, which is then filled with grout or concrete to form a solid foundation.

Once the piles are secured, a reinforced concrete slab or beams are laid on top of the piles to support the structure’s weight. The piles transfer the structure’s load to the stronger soil or rock beneath the surface, providing a stable foundation.

Advantages of Piling

Piling is a reliable foundation technique that provides numerous benefits to civil engineering and construction projects. It creates a stable foundation and supports the structure’s weight to prevent sinking and settlement, specifically in weak or unstable soil areas.

Another benefit is that it can support high loads used in conjunction with other foundation types and be easily adapted to suit the requirements of a construction project. Piling also causes a reduced settlement as the soil compresses under the structure’s weight, indicating damage prevention and prolonging the structure’s life.

When installed, piles act as a barrier and absorb the energy of vibrations before reaching the structure. This process reduces the vibration level, protecting populated surroundings and reducing potential damage.

Piling is also environmentally friendly as it minimises excavation and disruption to the surrounding areas. It is installed relatively quick, indicating the reduction of construction costs. Furthermore, piles can be installed in numerous weather conditions, which helps keep construction on schedule.

Piling Equipment

Numerous types of equipment are used in piling to drive piles into the ground to support structures. Each piece of equipment has its purpose, as it depends on the types of piles being installed, the soil conditions, and the job’s specific requirements.

Piling Rig

A Piling Rig is a heavy-duty machine used to drive piles into the ground. It typically consists of a large crane structure mounted on a tracked or wheeled base, with a powerful diesel engine that powers the hydraulic system used to drive the piles.

Piling rigs come in different sizes and configurations, depending on the type of piles being used to install into the ground and the requirements of the project. Some are designed to drive small piles for smaller structures, while some drive large-diameter piles suited for bridges and other large structures.

Pile Driver

A Pile Driver is a small machine powered by a diesel engine that drives piles into the ground. They are commonly used for smaller jobs or projects with limited access, such as urban environments.

It typically consists of a hydraulic or vibratory hammer attached to the end of a long boom. The hammer drives piles into the ground by vibrating it at a high frequency and striking it with a heavyweight.

Rotary Drilling Rig

A rotary drilling rig is a drilling equipment comprised of numerous connected pipes to form holes in the ground. It contains a large rotary drill attached to the end of a long drill stem, operated by rotating a motor. It grinds away the soil or rock at the bottom of the hole as the drill rotates.

Different types of rotary drilling rigs consist of truck-mounted rigs, skid-mounted rights, and track-mounted rigs. The choice of the rig will depend on the drilling project’s specific requirements, including the hole’s size and depth, the type of soil or rock being drilled, and the accessibility of the drilling site.

Hydraulic Impact Pile Hammer

This type of piling equipment drives piles into the ground by delivering a high-energy impact to the pile. The hammer has a hydraulic cylinder filled with oil and is connected to a ram that strikes the pile.

They drive concrete or steel piles into the ground for bridge and building construction, marine structures, and offshore oil and gas installations. They can deliver high-energy impacts with minimal noise and vibration, and their efficiency in driving piles to the desired depth.

Vibratory Pile Hammer

The vibratory pile hammer drives piles into the ground using vibratory forces. A clamp or grip to the pile is attached and then vibrates the pile is vibrated at a high frequency and low amplitude, allowing it to sink into the ground gradually.

It is generally used to drive sheet piles, H-beams, and other concrete and steel piles in soil conditions where impact pile hammers may cause damage to the surrounding structures or where noise and vibration restrictions are in place. This hammer is exceptionally effective in soils that are loose or have a high sand content and reduces cost and time by eliminating the need for excavation and soil removal.

Concrete Pumps

Concrete pumps are a piece of essential equipment used in piling as it helps transfer the concrete into the borehole where piles are being formed. Concrete is pumped through a pipeline and delivered to the piling rig, injecting the concrete into the borehole to form piles. This enables it to be placed in hard-to-reach areas and at great heights. The advantages of this include a faster delivery of concrete, increased efficiency, and cost-efficient. It also ensures that the concrete is placed accurately, which is crucial for the structural integrity of the pile.

More types of piling equipment are used across engineering and construction sites. Click here to find out more.

Types of piling

There are numerous types of piling, and each type used for an engineering or construction project depends on soil conditions, load-bearing requirements, and the overall budget. Below are a few common types of piling.

Bored Piles

Bored piles are a type of pile created using a drilling rug mounted on a crawler or truck to drill deep holes into the ground.

They are commonly used when the soil is too hard for other types of piling or if the supported structure requires a deep foundation. Bored piles have a very high load capacity and can be installed in various rock, clay, and soil conditions. Moreover, it has minimal settlement, deformation, and vibration. Bored piles provide strong and stable foundations for a particular structure and play an essential role in a piling construction site.

Bored piles are used in various infrastructure projects such as tunnelling, road, bridge construction, and flood protection. It is also used for slope stabilisation to prevent landslides from occurring and protect existing structures.

Continuous Flight Auger (CFA) Piles

Continuous Flight Auger (CFA) Piling are cast-in-place piles that involve drilling a hole into the ground using a continuous hollow stemmed auger. Concrete is then pumped into the hole through the auger’s hollow stem. Unlike traditional bored piling, where the hole is drilled and then lined with a temporary casing, the auger in CPA piling remains in the ground during the concrete pouring process.

This type of piling is vibration-free and gentle noise and is an environmentally friendly piling system suited to installation in unstable soil and urban environments. One of the benefits of CFA Piling is that it is a quick and efficient process, as there is less risk of soil, clay, or rock collapsing into the hole during the process. Since the auger remains in the hole when concrete is poured into the hole, there is less risk of the hole collapsing.

Diaphragm Walls

Diaphragm Walls are vertical concrete panels excavated under stabilising slurries to help form a continuous cut-off, retaining and structural wall. Piling Professionals use this in congested areas or areas that require excavation support and heavy foundations. It is generally used for underground retaining structures to support tunnels, basements, and deep excavations.

This technique involves excavating a trench in the ground, which is then filled with a stabilising fluid. The fluid helps to stabilise the trench walls and prevent it from collapsing during the concrete pumping process. The steel reinforcement is then inserted, and the trench is filled with concrete in small stages.

Micro Piles

Also known as mini piles, micro piles are a type of piling that involves small-diameter piles in the ground using specialised drilling equipment. The process involves drilling a hole into the ground and inserting a steel bar or tube. Once it is in place, the hole is filled with grout where it solidifies to create strong foundations.

It is a relatively fast and non-disruptive process, which can be used in tight spaces or areas with limited access. Since micropiles are smaller in diameter, they can be easily installed in the surrounding soil, reducing the risk of damage to existing structures.

Driven Piling

Driven Piling involves driving precast timber, steel or concrete piles into the ground using a vibratory or impact pile hammer. The piles are driven into the soil until a firm layer is reached to support the structure’s weight. Once all piles have been tested and installed, a cap or beam is mounted on top of the piles to transfer a structure load to the piles.

It is commonly used in bridge, building, and offshore construction projects as it can support heavy loads. They are extremely fast to install and efficient, making them a cost-effective foundation construction solution.

Screw Piling

Screw piles are helical anchors screwed into the ground to support the weight of a structure. They are made of steel and have one or more helixes that are screwed into the soil using hydraulic piling equipment. Screw piles act like columns that support the structure’s weight and distribute it evenly across the soil.

Typically used in areas with soft soil in coastal areas, they are quick to install as it is only a one-step process. Furthermore, it causes minimal ground disturbance since no hammering or thumping is involved in the process.

Sheet Piling

Sheet piling is used to drive thin sheets of steel, timber, or concrete into the ground to create a retaining wall or foundation. They are installed vertically to form a continuous barrier to resist soil and water lateral forces. Depending on the project’s requirements, sheet piles can be installed temporarily or permanently using vibratory hammer piling equipment.

This type of piling is typically used in construction projects requiring deep excavations, including tunnels, underground structures, and building foundations. It is also used for marine protection, riverbank stabilisation, and to create car parks. Sheet Piling provides long-term structural support and resistance to weather impact and causes minimal disturbances to the surrounding environment.

Piling is a widely used deep foundation technique in construction that offers several advantages over shallow foundations. With the use of modern equipment and technology, piling has become more efficient, precise, and cost-effective, making it a popular choice for many construction projects across Australia and New Zealand.

Demand for Piling Engineers

The demand for piling-related professionals in Australia and New Zealand has steadily increased over the years due to the growing construction industry and infrastructure development. As the engineering and construction industry significantly contributes to the Australian and New Zealand economies, employers are desperately looking for employees with a background in piling and other engineering and construction-related fields.

Different levels of experience are required to help deliver, plan and manage projects such as building roads, bridges, rail, and other infrastructure. The demand for engineering and construction-related professionals is driven by ongoing population growth and investment in infrastructure projects.

If you have experience in the piling industry, then get in touch with us today. We have many years of experience placing Engineers and Construction Professionals with our clients on various projects across Australia and New Zealand. Email your CV to [email protected] or chat with our Recruiter, Claire (Ya Chi) Yang on LinkedIn.

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