A Pile is a long cylindrical strong material made up of Concrete, Steel, and timber driven into the ground to support the excessive loads coming from the superstructure. Pile foundations are probably taking higher loads comparing to spread or mat foundations.

When designing foundations with Piles, the two main aspects to take into consideration are bearing capacity and settlements. For a foundation on clay, settlements are almost exclusively the limiting factor. The main reason for using piles in foundation design is to transfer applied loads to a greater depth of the soil. Deeper layers of the soil, due to their stress history, normally have higher strength and stiffness compared to more shallow layers and therefore would have greater resistance to settlement. When a pile is subjected to a vertical force from the top of the pile head, shear stresses are mobilized in the ground that surrounds the pile. If the created shear stress exceeds the shear strength of the soil, ground failure will occur. Two different parameters decide the capacity:

1. Shear stress that is developed in the soil around the pile toe
2. Shear stress is developed at the interface between the shaft and the surrounding soil.

Advantages:

1. Pile foundation is used when the superstructure load is heavier and the load distribution is uneven.
2. Piles are used in the waterlogged subsoil.
3. Pile foundations can be used for any type of structure.
4. Pile foundations are used in any type of soil.
5. Piles can be pre-made into any length, shape, and size and can be used on the site thereby reducing the time.
6. Pile foundation requires less storage space.

Disadvantages:

1. Skilled labors are required and adequate preplanning is essential in the proper handling of the pile when driven into the ground.
2. It requires heavy equipment in the process of driving the pile.
3. It requires more cost compared to another type of foundation.

When and Where to Use Pile Foundation

Pile foundations are generally adopted in the following situations:

• The sub-soil water table is exceptionally high which can undoubtedly influence different establishments.
• The overwhelming and uniform burden is going to the dirt from the structure.
• Where pontoon or grillage establishments are either expensive or can’t be received because of nearby troubles.
• When timbering of the removal channels is beyond the realm of imagination.
• At the point when it is difficult to keep up the establishment channels in dry condition by siphoning because of the overwhelming inflow of drainage or slender water.
• When the underneath soil is waterlogged and compressive. Hard firm strata are arranged at a more profound profundity.
• At the point when the structure is arranged on or close to coastline or waterway bed and establishments are obligated to be scoured because of the activity of water.
• Heap establishments can be utilized in the development of wharves, docks, or other marine structures as bumper heaps.
• Heap establishment can likewise be utilized as grapples.

Types of Pile Foundation

Pile foundations can be classified based on function, materials and installation process, etc. Followings are the types of pile foundation used in construction:

Based on Function or Use

1. Sheet Piles
2. Load Bearing Piles
3. End bearing piles
4. Friction Piles
5. Soil Compactor Piles

Based on Materials and Construction Method

1. Timber Piles
2. Concrete Piles
3. Steel Piles
4. Composite Piles

image

These piles are briefly discussed below.

Classification of Pile Foundation Based on Function or Use

image

Sheet Piles

Sheet piles are segments of sheet materials with interlocking edges that are crushed into the ground to give earth maintenance and exhuming support. Sheet piles are most usually made of steel, however, they can likewise be framed of timber or fortified cement.

Sheet piles are generally utilized for holding dividers, land recovery, underground structures, for example, vehicle parks, and storm cellars, in marine areas for riverbank assurance, seawalls, cofferdams, etc.

The choice of sheet piling is reliant on factors, for example,

• The kind of work, for instance. regardless of whether it is perpetual or impermanent.
• Site conditions.
• The necessary profundity of heaps.
• The bowing minutes included.
• The idea of the structure.
• The sort of security required.

Load Bearing Piles

End Bearing Piles

In end bearing heaps, the base finish of the heap lays on a layer of particularly solid soil or shake. The heap of the structure is moved through the heap onto the solid layer. It might be said, this heap demonstrations like a section. The key rule is that the base end lays superficially which is the crossing point of a feeble and solid layer. The heap in this manner sidesteps the powerless layer and is securely moved to the solid layer.

Friction Piles

Friction piles take a shot at an alternate standard. The pile moves the pile of the structure to the dirt over the full tallness of the pile, by the grating. At the end of the day, the whole surface of the pile, which is tube-shaped fit as a fiddle, attempts to move the powers to the dirt.

To envision how this functions, envision you are driving a strong metal bar of state 4mm distance across into a tub of solidified dessert. When you have driven it in, it is sufficiently able to help some pile. The more noteworthy the implant profundity in the dessert, the more burden it can bolster. This is fundamentally the same as how a friction pile functions. In a friction pile, the measure of burden a heap can bolster is straightforwardly proportionate to its length.

Soil Compactor Piles

Sometimes piles are driven at placed closed intervals to increase the bearing capacity of soil by compacting.

Classification of Piles Based on Materials and Construction Method

Two parts can primarily be classified as piles. Scrolling or non-scrolling substitution stacks. Are piles known as displacement piles that cause the soil to move vertically and radially as they move on to the floor? If heap repairs happen, the ground is bland, drained and either concrete or a pre-cast concrete layer poured into the resultant void. Load-bearing piles can be categorized as follows depending on the components of the pile building and its installation procedure:

Timber Piles

• Untreated
• Treated with Preservative

Concrete Piles

• Pre-cast Piles
• Cast-in-place piles

Steel Piles

• I-Section Piles
• Hollow Piles

Composite Piles

image

Timber Piles

Transmission of the burden through timber piles happens by the frictional obstruction of the ground and the pile surface. Timber piles demonstrate practical hit supporting light structures to be situated in compressive soils always soaked with water. The timber piles are produced using timber got from trees like sal, teak, deodar, babul, Khair and so forth. It has been discovered that piles produced using Khair wood can stand the activity of ocean water better and are consequently usually utilized for marine works.

Timber piles might be roundabout or square in cross-area. Heaps are driven with the assistance of a pile-driving machine in which a drop hammer conveys blows on the heap head. To anticipate the pile head from brooming, an iron ring around 25 mm less in distance across than the pile head is given at the pile top. To encourage driving, the lower end of the pile is pointed and is furnished with a cast-iron cone-shaped shoe. Heaps ought not to be dispersed under 60 cm focus to focus. By driving piles a lot nearer, the frictional opposition is decimated. The best dispersing for timber piles is 90 cm c/c. The greatest load on a wooden pile ought to typically not surpass 20 tons. Piles produced using sound timber free from any deformity or illness and driven in the dirt which is either for all time wet or for all time dry, will stay in great condition for a considerable length of time. Be that as it may, when exposed to exchange dry and wet conditions by virtue of varieties in groundwater level they get rotted. It is on this record timber piles are cut a little underneath the most minimal water-mark and topped with solid, steel grillage, stone or timber. In the event that timber topping is utilized, the top ought to be forever submerged.

Advantages of timber piles:

• They are cost-effective.
• They can be moved quickly and great time saves are therefore created when carrying out piling research.
• where piles would probably be exposed to extreme lateral movements, timber piles can be suggested because of their elasticity.
• They do not need heavy machinery or complex technical control.

Disadvantages of timber piles:

• For a more deepwater table at a location, increased excavation costs required with pile coating can make the option uneconomical if the water table at a place is at a higher depth.
• The piles of wood can not be pushed without damage in filled terrain and can not, therefore, be suggested for these regions.
• The waters or insects may decay or deteriorate.
• They can not be used for jobs where long batteries are needed, despite their restricted duration.

Concrete Piles

Pre-cast Concrete Pile

Precast concrete batteries can be designated as a stack molded in a circular, square, rectangular or octagonal shape. In a casting yard, the precast cement piles are cast and cured and then transported for driving to the site. When space is sufficient, the stack can be cast and processed at the worksite. The drivers are driven with the help of stacks in the same way as timber stacks. The pile usually ranges between 1 mm 35 and 65 cm in diameter and differs between 45 and 30 m in size.

image

Advantages of Pre-cast Piles

• It provides high chemical and biological cracks tolerance.
• They’re usually very powerful.
• A tube can be placed along the middle of the pile to allow riding.
• When the piles have been cast and ready to be driven prior to the installation stage, the speed of work can be increased.
• The reinforcement protection may be assured.
• The pile quality can be checked.
• If any error has been found, before moving it can be repaired.
• Pre-cast piles underwater can be driven.
• The batteries can be instantly charged after driving up to the duration required.

Disadvantages of Pre-cast Piles

• After the pile length has been decided, the
• length of the pile will be hard to increase or decrease.
• It is hard to mobilize them.
• Heavy and inefficient driving vehicles.
• Since they are not ready to buy, a pause in the plan can result.
• Possibility of breakage or damage while the piles are being handled and driven.

Cast-in-Palace Concrete Piles

A form of the pile is created by applying newly poured concrete on the surface to the appropriate depth and then by enabling it to cure. Either a metal shell is carried to the ground and filled with concrete, and the shell is released with the concrete, or the shell is pulled out while the concrete is poured.

Advantages of Cast-in-Place Concrete Piles

• The shells were easy to handle and measured loosely.
• The pile length can easily be varied.
• The cockroaches can be mounted in view.
• Only to prevent damages from handling is no excess enforcement needed.
• No deployment break chance.
• Easy to supply additional piles, if necessary.

Disadvantages of Cast-in-Place Concrete Piles

• Installation requires careful monitoring and monitoring of the quality.
• Enough on-site requirements for the storage of the construction materials used.
• Cast piles where the underground water stream is high is difficult to construct.
• The pile’s base may not be symmetrical.
• If the stack is not strengthened and not cast, the stack can fail when the stress acts and the lifting force is exerted.

Steel Piles

Piles of steel can be of the I or hollow pipe section. They’re full of concrete. Diameter can vary from 10 to 24 inches and usually 3⁄4 inches in thickness. The piles are easy to drive due to the small sectional area. Most of them are used as end-bearing stacks.

Advantages of Steel Piles

• They can be installed easily. 
• It can reach a higher depth than any other pile type. 
• The less cross-sectional region can penetrate the hard layer of soils. 
• The splitting of steel piles can be simple with heavy burdens.

Disadvantages of Steel Piles

• Corrosion prone. Prone.
• Does have the opportunity to deviate during driving. 
• Comparably costly.

The post What is Pile Foundation? Types of Pile Foundation appeared first on civilengineer-online.com.