The Significant of walls within the piling and foundation mechanisms

Sheet Pile Walls

Sheet piling system is founded upon using pre-installed piles as the reaction force for installing subsequent piles and continues by working along the line. The system has an added benefit of being able to work in restricted regions including cuttings and on sloping railway embankments or over the water.

Diaphragm Walls

Diaphragm wall refers to some underground structural elements typically utilized as permanent foundation systems and retention walls. Diaphragm walls can be designed to take high structural loads and tend to be utilized for retaining deep excavations. Diaphragm walls feature exceptional water tightness ability compared to secant walls. As a consequence, they have few joints and can also be employed as groundwater barriers.

Lagging Wall and Soldier Pile

Lagging wall and soldier piles have successfully been employed since the late 18th century in various metropolitan cities like New York Berlin, and London. Therefore, they are among the oldest forms of retaining systems utilized in deep excavations. Lagging walls and soldier piles are fast and easy to construct. They are also the cheapest systems compared to other types of walls. The price point of these walls make them an attractive option for many contruction and civil engineering contractors and companies. The lagging bridges retain soil across piles and transfer the lateral load to the soldier pile system. Passive soil resistance is achieved through embedding the soldier piling beneath the excavation grade. Moment resistance in lagging walls and soldier pile is offered solely by the soldier piles.

Retaining Walls

Embedded retaining walls are employed in various civil engineering applications, especially in buried structures such as tunnel approaches or underpasses, construction of basement walls, and embankment stabilization. The common types of retaining walls include secant pile walls, contiguous pile walls, and soldier pile walls.

https://en.wikipedia.org/wiki/Retaining_wall

The Importance of Retaining Walls

Retaining walls can be employed in both permanent and temporary conditions. The use of ground retaining walls is a superb way of minimizing the bulk excavation required to achieve the preferred ground profiles.

The process and conditions in which the wall is to be utilized determines the cost of building retaining walls. Some of the aspects considered when designing a retaining wall include the design life, desired wall geometry, propping options, and acceptable deflections, retained height and ground water and soil conditions. These factors are usually deliberated over by both the civil contractors as well as the owner of the land.

Tangent Pile Wall

Tangent piling walls are a variation of soldier pile walls and secant pile walls. They are usually easier and faster to construct. They also have increased construction alignment flexibility. Tangent pile walls are mainly designed with no overlap, and ideally one pile touches the other.

The above video shows the process in which a RW is built.

Kingpost Walls

Kingpost walls are usually employed as temporary retaining walls. A kingpost (open bore filled with concrete to create a base for steel H-pile) is used in this type of piling system. Steel sheets, precast concrete or panels of timber can then be slotted into the steel H-piles to develop a retaining wall.

Deeper look into Contiguous Flight Auger Methods

CFA Piling

Continuous Flight Auger (CFA) technique joins the benefits of fixed piling with the versatility of the drilling applications of piles. Depending on the soil consistency and diameter, the depth is usually 15 to 33m. The pile diameter is usually 400 to 1400 mm. Reinforcement cages can be inserted in the concrete while still wet to reinforce the whole length of the pile. The auger is extracted after has been poured throughout the internal hollow pipe, on completion of the boring operation. The construction process includes boring the soil using a continuous flight auger that is usually assembled on a central hollow pipe.

The lateral soil compression raises the final load bearing capacity during CFA piles construction. The instrumentation on the piling rig is used to determine the rate of flow and the concrete pressure. The concrete is only pumped via the hollow stem auger after the right depth has been reached as indicated by the pile design and investigation. A majority of piling professionals prefer CFA technique because of the minimal vibration involved when a stemmed auger is screwed into the ground using the piling rig. Minimal vibration improves the safety of contractors and lowers labour costs.

Main Benefits

Using CFA helps to reach high industrial production easily. The minimum needed equipment assists to operate in very restricted areas and reduce the job site installation plant. Costs are greatly lowered when the logistics of equipment is low. The technology can be used in urban areas because it does not produce noise, vibrations, and shocks. The technique can be employed in both cohesive and non-cohesive soils, either in the presence or absence of a water-bearing stratum and without the need to use bentonite fluid as wall support. CFA can be constructed in a majority of ground conditions because the side of the excavation is usually supported by the pressure in the concrete which reduces the chances for the hole to collapse. Reinforcement can be placed by hand, piling rig or by an excavator. The surplus material is usually removed by an excavator once the excavation is complete.

Contiguous Pile Walls

Contiguous walls are usually used where water retention is not a priority. Contiguous walls have been shown to dispense with intercut completely where soils are cohesive. The types of walls are suitable for various soils where the underground water lies below the optimum excavation depth. Contiguous piles are most often than not employed in permanent situations.

In summary, your choice of piling system can be determined by the intended use, budget, and the prevailing ground conditions. It is advisable to consult experts before selecting the ideal pile systems for you. Construction Engineering companies such as Civil Assist Australia are known experts in this field. The crucial components of any foundation are piles and pile caps. Pile foundations are vital parts of structures that are used to carry and transfer the load of the building to the bearing ground positioned some depth below the ground surface. Always choose a piling system that best suits your personal budget and needs.

https://en.wikipedia.org/wiki/Deep_foundation#Augercast_pile

A look into Marine and Secant Processes

Secant Piling

Secant pilings are primarily employed where there is a high water table or unsuitable ground conditions. The piles are a unique way of designing retaining walls and are developed by a series of interlocking bored concrete piles. Your ideal secant piling experts should be able to offer complete foundation and basement packages including propping, temporary load anchoring, bulk excavation, capping beams, circumference piling, setting out and design.

Main Advantages of Secant Pile Walls

The pile lagging the walls between the two major beams should be reviewed for compression and shear arching. Secant pile wall design, where steel beams are utilized, entails the use of weaker that usual concrete. Secant pile walls have less noisy construction. It can be installed in a difficult ground (boulders/ cobbles). Secant piling also has increased wall stiffness compared to sheet piles. It also has increased construction flexibility.

Marine Piling

Marine piling involves designing tubular piles in an open-ended architecture to enable deeper penetration. Soil plug is developed inside pipes in this technique of pile formation. On the contrary, close-ended piles obviate the soil from entering the pipes. Various experiments have ascertained that the end bearing capacity lowers with an increase in the plugging ratio (the ratio of the soil plug to the length of the pile penetration). Therefore, the plugging ratio significantly affects the load carrying capacity of the piling system.

Sleeves can be used in the lower part of the open-ended driven piles to strengthen the longer length of the installed driven piles. Open- ended piles are essential for providing better lateral resistance against lateral loads such as berthing loads in a majority of marine structures. In most cases, open-ended piling is used more often than close-ended piling to boost the longer length of piles being installed.

https://en.wikipedia.org/wiki/Deep_foundation

The Significance of Reinforced Concrete Infill

The gathering of frictional forces between the steel piles and concrete infill is fundamental to ensure that piles function properly. The loads from reinforced concrete infill are usually transferred to the steel tubular piles via a frictional force between the steel piles and the reinforced concrete. The loads from pile caps are usually transferred directly to the reinforced concrete instead of tubular piles. The steel tubular piling above the seabed is usually assumed in design to be entirely corroded when approaching the end design. The reinforced concrete is primarily designed to fill the void space inside the steel tubular from pile cap to a specific distance below the seabed.

There are multiple benefits and features when it comes to using Marine or Secant piling mechanisms. There can be an array of reasons why a civil engineering company or construction engineering company choose the piling mechanism at hand. It is usually dependent on the depth of the water table, flexibility of the pile and reason in which contractors have been employed to secure, load and infill these piles.

In the next post we will explore the range of methods involved in foundations, the processes behind them, why that particular method has been chosen and the benefits of each.

An Overview of Various Piling Techniques: Screw Piling

Factors that may influence your choice of piling system include the cost of installation, durability, and your preferred material. The ideal pile material is determined by the type of soil. The common types of material utilized for piling include concrete, steel, and wood. The piles designed from the three materials are usually jacked, drilled or driven into the ground and linked to pile caps. Piles are primarily slender and long and are used for transferring the load to a rock of high bearing capacity or deeper soil preventing shallow soil of low bearing capacity. The integral components of a foundation are pile and pile caps.

The video above gives a clearer indication of how screw piles and piers are inserted into the ground. This can be a lengthy process due to safety standards and regulations.

 

The Different Types of Piling Systems

  1. Screw Piling

Screw piles are also known as helical piles. Depending on the prevailing ground conditions, helical steel plates are usually welded to the pile shaft. Screw piles are designed in a variety of sizes of hollow tubular sections for the anchor-shaft or pile. The helical piles are a robust ground anchoring system employed for building deep foundations.

The Minimum Design Life

The design life via sacrificial corrosion is usually in excess of the specified life. The thickness of the pile shaft depends on the strength it requires to be installed in the ground. A design life of fifty years means that the piles will at least have the capacity to withstand the original design loads even after fifty years.

Do They Corrode?

Corrosion needs to be factored in all designs because all steel corrodes. However, corrosion can be addressed in either of the outlined two ways:

-Surface protection can be applied to the steel to minimize the rate of corrosion.

-A predetermined rate of corrosion (sacrificial corrosion) can be allowed based on the accepted standards.

https://en.wikipedia.org/wiki/Screwpiles

How They Are Connected

The most typical technique of linking a screw piers system to the foundation involves casting the head of the screw pile into the structure’s foundation. The reinforcing bars usually have a standard right-angled bend that is sometimes substituted for Reidar enhancing with foot plates or flange nuts screwed onto their ends. The fixity is mainly accomplished via steel reinforcing bars that are usually cast into the piles and protrude into the footing of the house. Both structural and geotechnical input is required while designing the connection. The interface between the pile and the building and is a crucial part of the design and needs lots of care.

Main Benefits in Modern Use

They are usually sued for retaining structures, signs, and masts because they are suitable for both compression and tensile loads. Screw piling systems are also ideal because of their reduced costs, minimized risks to the workforce, and ease of removal when the particular foundation is no longer needed. Other benefits of screw pile foundations include reduced carbon footprint, ease of access, ease of installation and shorter project times.