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The advantages and disadvantages of CFA piling method

There is no one size fits all answer to piling. Different jobs require different methods in order to extract earth and to drive the piles, whether it be because of location, budget restraints or from other restraints that may affect which method can be used effectively and safely.

Continuous Flight Auger (CFA)

CFA forms a pile by using a helical auger that works on the same principle as a household screw. The helical nature of the auger extracts the soil as it is driven into the ground through a circular motion. Once the ground is extracted, concrete is installed by injection under high pressure through a hollow central stem which is fed through slowly as the auger is removed. Into the wet concrete, pile reinforcements, usually in the form of steel cages, are lowered by crane.

Advantages

CFA provides minimal levels of vibration, lower noise levels from the piling rig itself and is more suitable for tension loads at stability elements depending on the ability to install the cage prior to the drying of the concrete.

Disadvantages

If the piles are being driven into sand below the water table then they require driven steel casings to be installed, otherwise the pile bore can collapse. They also require longer piles than driven which ultimately results in longer continuous noise exposure to the driven piles.

Issues with the removal and disposal of potentially contaminated soil do arise in certain locations. In these cases, plans need to be placed before work commences so that soil is dealt with in a safe and timely manner.

Installation programmes for CFA commonly run for 8 weeks which is one of the longest programmes and potentially one of the most expensive.

The process also involves more construction traffic to accommodate the delivery of steel and concrete and to remove any arisings. Cranage is also required to install pile reinforcements.

A major concern with CFA is the risk of in situ concrete drying out due to the leakage of sand which can cause problems with the installation of the steel cages.

Contact the team at Rhino piling for more information on piling in Manchester.

 

How To Prepare For Piling Work On Your Home

Any type of piling or underpinning work on your home will incur a certain amount of disturbance, which will obviously vary depending on how extensive the damage.

Some foundation problems can be so extreme that people have to leave their home for a period of time as the damage can put lives at risk. Other jobs can be relatively simple and homeowners can continue to live in their home as work takes place. It all depends on the job at hand.

If you are having work done on your home by any piling contractors, you don’t need to pack your bags just yet. Here is our guide to prepping your home for piling work to take place.

Prepping your home

Piling work is similar to any other construction work in that any rooms that will be affected by the construction should be cleared.

Before work begins on your home, it is always a good idea to prepare as much as possible beforehand. Not only does this help workers get started quicker when they arrive, it also makes sure none of your valuables are at risk of being damaged as the work takes place. Move as much furniture as possible into other rooms or place them into storage if there is not enough room in your house.

Dust sheets are also a good idea as debris and dust is likely to find its way around your home. Workers will always attempt to keep any mess to a minimum but with building work like piling and underpinning, there is always going to be a certain amount of mess to contend with and any preventative method you can put in place is a wise choice.

Letting your neighbours know

Nobody wants to fall out with their neighbours over noisy building work so make sure you let those living within earshot, what work you will be having done and on what days. You never know who may be working nights or on separate shifts or who has young children that may be disturbed by loud construction work going on underneath their windows.

Building contractors will only operate during appropriate daylight hours, and simply giving your neighbours a heads up about future work will usually help avoid any surprises.

Having work done whilst living at home

We understand that it is incredibly disruptive to have to move out of your home for any building work to take place, so we only recommend it in extreme conditions when safety is at risk.

It is much more common for homeowners to simply section off the area of the home that will be affected by the work, rather than uprooting your entire family. If an important area like the kitchen is going to be out of bounds during construction, make sure you have temporary alternatives in place; either a makeshift kitchen elsewhere in the house or a pile of takeaway menus at the ready!

For more information on prepping your home or on piling in Cheshire, contact the team at Rhinopiling today.

 

 

The importance of understanding soil mechanics for piling applications

To be able to install appropriate piling, underpinning or auguring we must first take into account the characteristics of the soil in which we will be working on. Soil essentially consists of three different phases which all interact with each other indifferent ways: solid, liquid and gas phases. The characteristics of the soil will depend on how these three components interact with each other and on the stress applied to the soil.

The solid phase of soil is made up of clay, non-clay minerals and organic matter. We look at the sizes in terms of clay, sand or gravel. The liquid phase is composed of water contained in the soil. This water also contains organic compounds absorbed form chemical spills, waste and ground water. Even when soil is compact, it still contains air, which we categorise as the gas phase.

The science behind soil mechanics is known as soil mineralogy and looks at how the size, form, chemical properties, compressibility and load carrying capabilities of the soil all interact with each other.

By studying this discipline we can predict the soil performance and apply the correct engineering techniques accordingly. Soil mechanics has become a major part of engineering because each soil interacts differently when we integrate piling applications. Using the wrong engineering technique for a given soil type can cause the piling to be ineffective and even cause the construction upon the foundations to become dangerous in the future.

If a structure is to be built on a fine-grain soil with low permeability, for example, the flow of water through the soil voids will be reduced which can cause the soil to dry out and undercut strong foundations. On the other hand, high water content in the soil can cause heavy structures to sink under its own weight.

We take soil mechanics into account for each application of piling in Manchester to ensure that our foundations are suited to the exact requirements of the ground it resides in.

 

 

The Role Of Piling Dollies

Certain applications require a pile driver in order to force the piles to an appropriate depth able to withstand the weight of the construction above it. Driven piles are one such option for a lot of applications, it does tend to throw up some problems, however. Driving piles using a hydraulic or diesel hammer requires the column to be driven through high-impact hammering. This high impact produces high levels of intermittent percussive noise pollution as well as higher levels of intermittent vibration. So, what can be done to help reduce these problems?

One such solution is the installation of driving dollies. Also referred to as pile cushions, these dollies sit between the head of the pile and the ram driver and are designed specifically to reduce the impact of the hammer on the pile head, reducing both the levels of noise and vibration pollution yet still being able to transfer the strength of the blow into the pile, driving it into the ground.

Not only does the presence of a piling dolly reduce the noise and vibrations that occur, it also reduces damage to the pile head itself, ensuring a much longer lifespan for all equipment and eliminating a lot of repair that used to be required more frequently when these pieces of equipment are operated without a dolly.

The dollies themselves are usually made from specialised plastics which offer excellent impact strength and are incredibly durable and able to withstand some serious punishment. Not only are they beneficial if companies need to reduce noise and vibration pollution, especially if they are working in built up areas, they are also incredibly easy to install thanks to their light weight and are actually great value for money.

Rhinopiling provides piling in Manchester, if wish to find out more details or are looking for a quotation, contact our team today.

Deep And Shallow Foundation Types

Without the proper foundations in place every structure will soon crumble. Foundations are essential in providing the proper base to support a building and keep it upright. Without a secure footing to keep a building level, the weight won’t be evenly distributed causing sections to crumble and fall away and eventually for the building itself to collapse.

Determining which type of foundation for any given building is a specialist job and requires a trained eye to recognise the requirements and to weigh up all the factors: from the weight of the building, wall construction type and height, soil type, slope gradient, budget and drainage requirements.

What are the different foundation types typically used on UK buildings?

Shallow foundations

Most domestic properties use some sort of shallow foundation as well as other smaller buildings and can be made at depths of as little as 3ft. Shallow foundations come in a number of different types:

Individual footings

These are the most common foundations types you will find across the UK for their reliability and durability. They are typically used when the load of the building is supported by individual columns. These columns help spread the weight of the building horizontally across an area large enough so that the bearing strength of the soil underneath is not exceeded.

Strip Footings

If a building is supported by entire walls, rather than isolated columns, a technique called strip footings is used. These are installed by excavating trenches which are then filled with concrete before being built up to ground level using blockwork and the walls are switched to stone or brick.

Raft or Mat Foundations

When buildings are constructed on weak soil then this process is utilised. You will often see this technique used in houses where an entire basement floor acts as the building’s foundation, generally constructed of one solid piece of concrete with the buildings weight spread evenly over this base.

Deep Foundations

As the size of the building increases, we need to use different foundations in order to support the increased weight. As the taller a tree grows, the deeper and more widespread the roots must travel, the higher a building goes, the deeper the foundations need to go. Deep foundations are also used if the underlying soil is unsuitable at the surface and the foundations need to be built down to more secure, stronger soil or even solid rock.

Pile foundations

It can be a noisy technique, but an essential one. For this, prefabricated, cylindrical piles consisting of concrete, timber or steel are driven into the ground until they reach ground firm enough to hold. They come in two forms:

  1. End Bearing Piles – These piles are driven deep enough so that the bottom rests on a layer of very strong soil or rock, deep underneath the topsoil. The building’s weight is then transferred through the pile onto the more secure layer, completely bypassing the weak soil surrounding it.
  2. Friction Piles – If secure soil or rock is too far to be reached by end bearing piles then friction piles can be driven into the ground. Instead of supporting the weight on the columns themselves, these piles transfer the weight of the building across the soil via friction.

For piling in Manchester, contact the team at Rhinopiling today.

Underpinning Solutions

When a building becomes weakened to the point of being structurally unsafe, instead of having to demolish and rebuild large parts or even the entire structure, underpinning can be used to strengthen the foundations of the existing building or structure.

Underpinning works by extending the depth of the foundations or expanding the foundations to increase the weight bearing load over a larger surface area. Underpinning can be a major project to undertake so it is important that you know the different methods available and how they can benefit different situations.

Underpinning can be required for a number of reasons; maybe a change in soil conditions have altered the foundations; maybe the original foundation is old and worn and no longer strong enough to support the structures; maybe additional floors or extensions have been added to the structure which means the foundations are now under increased pressure, pressure that they are unable to withstand. Luckily, there is an underpinning method for every eventuality:

  1. Mass Concrete Underpinning

One of the most common methods of underpinning sees the soil underneath and immediately surrounding the structure replaced with concrete which is poured in box shaped compartments, pre-dug by the underpinning team in a predetermined sequence that will be able to bear the weight of the structure. This method is commonly used for relatively shallow foundations.

  1. Piled Underpinning

If a structure is situated above layers of firm and superficial soil then piling underpinning is used. Piling underpinning is also considered if there is limited access to the construction site, any environmental concerns or minimal structural movements during the underpinning process. Steel cased piles are driven at strategic points before being filled with the concrete.

  1. Jet Grouting

Suitable across a wide range of soil types, jet grouting involves creating geometric patterns of grouted soil using a high-velocity jet. The jets are used to create columns of grouted soil which can withstand greater loads than the previous soil. Because the grouting is applied using high-pressure jets the current soil is disturbed, which means the process can never be used if the foundations are very sensitive.

For more information on underpinning and piling in Chester, contact the team at Rhinopiling today.

 

 

3 Things That Cause Subsidence

As the number one cause of early deterioration of a properties structure, it is much more effective to try and prevent subsidence before it manages to take control. After all, it is relatively easy to spot the signs of its development when it is severe, however, the costs associated with a fixture can be unaffordable for many. Luckily, understanding how subsidence is caused can help property owners stop it in its tracks sooner rather than later. Read on to find out more…

Moisture loss can cause soil shrinkage and movement

In most cases, subsidence occurs as a result of soil movement and displacement which affects the way that the foundations of a property lay in the ground. In fact, soil movement can actually drag the walls of a building apart and this often leads to the signature diagonal split that appears in the brickwork of properties affected by subsidence. This is often the result of moisture loss in the soil causing it to shrink in size and move and if foundations are built upon this weak soil then they are at continuous risk of subsidence.

Trees and other plants can cause foundation damage

Many people are unaware how strong tree roots and plants can actually be when it comes to the foundations of a property. In fact, the number of subsidence related incidents that involve plants are actually increasing each year. The affliction is often caused when a structure is built on top of or within a close proximity to nature itself and plants like Japanese Knotweed can actually break through foundations and crumble them whilst tree roots suck up excess moisture and cause soil shrinkage to occur. As a result, it is vital that foundations are installed in a suitable area as far away from plants and trees as possible.

A building with poor foundations will eventually subside

Perhaps the most unusual cause of subsidence is the quality of a structures existing foundations. After all, the weight of an entire building has to be able to sit on top of them and if they are installed incorrectly or do not offer the necessary support then they will begin to buckle under the sheer weight of the structure. In most cases, this presents itself as subsidence.

Here at Rhino Piling, we believe that subsidence is an avoidable affliction that many property owners shouldn’t have to deal with. After all, poor-quality foundations are a common cause of its development. Luckily, the installation of piles can help rectify subsidence before it manages to wreak serious damage to the structure of a property and can even be used as a subsidence prevention measure. To find out more information, get in contact with the best piling Manchester has to offer and speak to a member of the Rhino Piling team today!

 

Can the Weather Affect Piling Construction?

Before a piling project can commence, there are many guidelines that have to be abided by. For example, a site evaluation must be carried out in order to determine which piles are best suited for the property in question and the time of year has to be factored into the approach of the project. After all, the weather can have an adverse effect on piling construction and extreme conditions may even temporarily halt a job all together. Read on as the team here at Rhino Piling go over the different ways that the weather can affect piling…

Cold weather can freeze the ground

During the winter months, it is not uncommon for the soil to freeze and this can make a traditional piling project difficult. After all, the methods used in order to install piles tend to rely on the shifting of soil and this cannot be done when the temperatures fall below zero and cause it to freeze. In addition to this, concrete mixtures may have to be kept at a constant warm temperature until it is used which means that heaters often need to be set up, adding to the expenses of a project. Luckily, helical piles are often suitable for winter piling construction.

Hot weather can lead to soil shrinkage

Although the summer season is said to be the easiest times of year for piling construction and installation, there are several hurdles that builders and contractors may have to take into consideration. For example, extremely high temperatures can cause the moisture from soil to be depleted and this can lead to soil shrinkage and movement, affecting the piles before they are secured.

Wet weather can make the soil weak

When torrential rain strikes, it is not uncommon for a construction project to be called off, particularly when it deals with groundworks like piling. After all, rainwater can quickly merge with the soil in order to create a slurry and this can make a work environment incredibly unsafe. In addition to this, very moist soil can also make it difficult to accurately install deep piles into the ground.

Here at Rhino Piling, we believe that one-to-one customer care is essential in order to ensure that a project runs as smoothly as possible and that is why we make it our mission to stay in contact with our clients at all times. After all, heavy rain or strong winds can make a piling project virtually impossible to complete. To find out more information about the guidelines that make up our services, get in contact with the best piling Manchester has to offer and speak to a member of the Rhino Piling team today!

 

Plants That Can Damage the Foundations of a Building

When people think about foundation damage, they tend to presume it was caused by soil movement or shrinkage that eventually led to late-stage subsidence taking hold. Surprisingly, nature itself can be the culprit as there are many plants that have the power and strength to completely destroy the foundations of a structure unless dealt with by a professional. Here at Rhino Piling, we want to equip our readers with everything they need to know about our services and that is why we have decided to go over three potentially dangerous plants that should be prevented at all costs. Read on to find out more…

Japanese Knotweed

Identified by its bamboo-like stems, Japanese knotweed is every property owner’s worst nightmare. After all, it may only grow up to 3 meters in height but it is incredibly difficult to get rid of as it has the ability to survive from a root the size of a small fingernail. Once a property is affected by Japanese knotweed, it is important to act fast because this plant grows as fast as 10cm per day and has the strength to force its way through concrete, drains and even walls which can cause devastating damage to a buildings foundation and may even lead to subsidence. In order to remove it, the roots must be completely dug out and burned by a professional.

Oak Trees

Although a tree may appear harmless, their roots tend to spread in order to take up a space that is four to seven times wider than their crown. This means that a tree located within close proximity to the foundations of building can actually cause a lot of damage to the structure. After all, the roots are also incredibly strong and, just like Japanese knotweed, have the ability to force their way through concrete and drainage pipes. In addition to this, roots also soak up moisture from the soil in order to survive and this can lead to shrinkage and eventually subsidence. In order to remove an oak tree from the roots, it is important to call a licenced tree surgeon.

English Ivy

Whilst it may look aesthetically pleasing when it grows on the exterior of a property, English ivy has a wrath that can sometimes affect the foundations of a property in a variety of ways. This is because they support themselves by using a root system that penetrates through the brickwork. Whilst this type of plant isn’t as dangerous as tree roots or Japanese Knotweed, it is important to have the foundations inspected regularly as English ivy can lead to damp interior walls and structural damage over time.
Although a simple plant may seem like a minor bump in the road, there is nothing more unfriendly than the discovery of these plants, particularly Japanese knotweed. After all, a building can be completely ravaged by its growth unless it is dealt with promptly by an expert who knows how to kill it from the roots. Luckily, high-quality piling foundations can provide a structure with all the strength it needs in order to withstand the brutality of these plants until the property owner notices the problem. To find out more information, get in contact with the best piling Manchester has to offer and speak to a member of the Rhino Piling team today!