When you are establishing a foundation for a building, you need to address the condition of the ground and provide the right equipment. Therefore, it is essential to work with a company that offers contractor services that include piling foundations, underpinning, and mini piling in its service listing.
Common Piling Techniques
Common piling techniques can include mini piling using auger boring and driven piles, continuous flight auger (CFA) piling, screw piles, Grundomat driven piles, and continuous piled retaining walls.
Rigs for mini piling are a logical solution for piling works that are located at smaller sites where the access is normally limited. You can use mini piling for a broad range of constructions, including residential extensions, building plots that are detached, conservatory foundations, or at environmental sites.
Mini augured piles are available for installation in the common diameters of 150mm, 200mm, and 300mm. Steel cased bottom driven mini displacements measure 75mm, 100mm, 150mm, 168mm, 193mm, 220mm, 273mm, and 323mm. Mini piling methods come with complete anti-heave precautions, if necessary.
The CFA piling or continuous flight auger piles are a viable solution for any piling works that take place on bigger open sites or sites where the ground is considered unstable. Using this technique makes it possible for the auger to remain in a pile bore to the last depth. The auger is then removed gradually and concrete is directed through the auger’s hollow stem and into the pile.
This method of piling is quieter and is appropriate for creating piles in a variety of ground conditions, thereby making the method helpful for sites that are rendered as noise-sensitive locations. CFA piles come in such diameters as 300mm, 3350mm, 400mm, 450mm, 500mm, and 600mm. The method comes with complete anti-heave precautions, if necessary.
Screw piling, made of steel, is a feasible solution for underpinnings and foundations that cannot make use of a piling rig. Screw piles can be added in situations where there is restricted access. Usually, a two-man crew is used or a mini excavator with an arm. Up to twenty-five screw piles can be installed in a day, which also reduces the costs of labour substantially, especially when compared to the use of conventional piling techniques.
Steel screw piles can work in both compression and tension, which makes them the preferred choice for underpinning work where they are utilised in connection with support brackets. Using screw piles creates almost no spoil, which saves by not having to spend money on muck-away expenses. The piles are offered in various sizes and lengths that feature working loads of over 400 to 500kN.
Grundomat Driven Piles
A Grundomat driven pile is used in situations where a driven pile is needed at a site where access is an issue. The piles, which are driven by a Grundomat driving hammer, offer one of the most versatile and adaptable solutions for locations that are otherwise off-bounds or restricted.
The piles are made with the minimum of vibration—necessary when piling needs to be performed at a noise-sensitive site. These piles are recommended for conservatories and extensions located in built-up locales. Diameters are typically featured in 100mm, 150mm, and 165mm sizes. Working loads for piles can accommodate up to 130 kN.
Contiguous Piled Retaining Walls
A contiguous piled retaining wall is generally used with augured piles to create a partial retaining wall situated underground. Therefore, this type of piling is used for basement excavations or for decreasing ground levels whilst retaining other tiers. The piles are usually placed about 50mm to 100mm apart, depending on the ground’s condition. They are linked on the top with a reinforced concrete beam.
When you select a piling service, make sure the company also offers other groundwork services, such as the excavation of footings, steel fixing, concrete formwork, and drainage. Piling contractors should also offer a variety of underpinning services for ground level reduction and subsidence.
The conventional underpinning technique entails the excavation of an affected structure with individual sections removed in a hit-and-miss type of sequence. Therefore, each hole that is dug is excavated to a pre-calculated depth below a building’s foundation.
After an inspection, each dug pit is back filled with concrete. The traditional underpinning technique requires that this process is repeated until the entire area is strengthened. This type of engineering task can be very cost-efficient since it provides use of a building while the foundations are being modified.
Underpinning using screw piles and brackets offer a solution in cases where a traditional underpinning method is considered impractical, either due to excessive depths or unsuitable rigging. These underpinnings can be installed with a mini excavator arm or by hand with a two-man crew.
Just as in screw piling, it is possible to install as many as twenty-five screw piles per day to reduce the costs of labour. Again, screw piles create almost no spoil, and muck-away costs are minimal. The piles work with compression and tension and are helpful when used in connection with a support bracket.
Pile and Beam Underpinnings
A pile and beam underpinning is often utilised when a traditional underpinning system is deemed uneconomical or an entire property has been affected and urgently needs repairs. In this type of work, all the existing floors of a building are pulled up and a pit is dug while mini-piles are constructed. Pockets of brickwork are removed, and the reinforcement is made per an engineer’s specific directions. In the final stages, the site is inspected and then concreted. This technique is ideal for the laying down deeper foundations over, in some instances, tree roots or a drain network.
Cantilever Pile and Beam Underpinnings
A cantilever pile and beam underpinning is similar to pile and beam underpinning. However, the piles are used in tension and compression, and the work is carried out from outside a property, thereby saving the customer substantial expenses in the removal of fixtures and inside floors. This method is often used with screw and conventional piles in connection with Helibeam masonry reinforcement.
Piled Raft Underpinnings
A piled raft underpinning is facilitated when a whole property’s foundation has been affected. All the existing floors are taken out and mini-piles are built. Pockets of brickwork are extracted and the reinforcement is made per an engineer’s recommendation. The building is inspected and concreted in the final stage.