Have you ever wondered how the buildings erected on the surface where the topsoil is feeble and nearly incapable of underpropping superstructures? The inadequacy of such characters to bear superstructure weight is covered and backed by a driven Pile.
In this article, we will be clueing in the readers on driven concrete piles, What Is a Driven Pile? It is its type, why it is constructed/used in buildings/structures, and other relevant questions.
What Is a Driven Pile?
A Driven pile is a long, slender column provided to support resisting forces made from a material having a predetermined shape and size. The driven concrete pile is a prefabricated element that was done on the ground by percussion, pressing or vibration with the help of machinery.
This driven pile foundation is optioned for when constructing bridges and low-rise buildings, so a load of such structures could easily be borne.
Such piles are shoveled up to the hard layer in the soil(as the topsoil lacks the ability) where the needs of bearing and skin friction are met. This is precisely why driven piles are such, of all.
How Does Driven Piles Work?
Dealing with driven piles may be quite complex for novices as you have no prior knowledge of handling such foundational piles.
Pilings work by shifting the load to a much deeper level than what is possible with a conventional shallow foundation. In piling, concrete/steel, wood piles are driven deep so that the foundation stays still, and whichever building sits on top wouldn’t be affected by any catastrophic or artificial event. These piles come in vertical forms like most of the foundational equipment.
One is sure to be baffled if they are told that these pilings were made of timber before things changed. Over time, the composition has observed a considerable change. For now, concrete or buttressed concrete is used. These piles are stuck into the hard layer to avoid buoying up buildings or collapse of the same.
The execution method used in the construction of the driven plies is speedy, and it does not depend upon the local conditions. The driven plies are best suitable to be used in the soil consisting of hard rocks.
Purpose of Pile Driving
Driving pile deep into the deep structures could be for numerous reasons, with the prime reason being circumventing catastrophic situations that may lead to the uplifting of any structure sitting on the surface or even collapsing of superstructures like bridges or low-rise foundation buildings.
Once the pile is buried deep into any surface, the building that is most likely to be constructed on it would remain unwavering, especially when someone lives in an area where topsoil could easily be disturbed by water; these piled foundations come in useful and are always sought for.
Acceptance Criteria for Driven Piles Foundations?
The following heading delves into the prerequisites of such driven pile foundations. The following are the same conditions or criteria in question:
- The first condition for pitching on driven pile foundations over others is that the area/surface being dealt with has a layer of weak soil. Since the soil cannot by itself cannot hold up the weight of the building, the burden must bypass this layer and be shifted to the stronger soil layer or the rock, just below the weak layer of soil. This is the first acceptance criteria for going for driven pile foundations.
- According to the design and design, the pile should be driven up to the hard soil layer, which is identified as the termination level. The termination level mainly depends upon the information provided in the soil investigation report.
- Another condition for fixing such foundational piles is when buildings have exceptionally heavy concentrated loads- high-rise structures, bridges, and water tanks, just to name a few. In such a condition, one may be hyper-fixated on this alternative to fighting shy of overloading weight.
- According to the design, the pile should be driven up to the hard soil layer, which is identified as the termination level.
- The design of the driven pile and its selection of the termination level will be based on the information provided in the soil investigation report. When it reaches up to the termination level, the movement of the pile will get reduced.
- Such driven pile foundations may very well be capable of shoring up higher poundage than those spread footings that distribute the weight. If you happen to live in an area that fulfills the above criteria, you may have to consider inserting such vertical columns.
Types of Driven Piles
There are several types of driven piles one can choose from. You can go over them and see what works the best for the soil structure and layer around you.
The different types of driven pile foundations are outlined below:
- Steel Driven Pile foundations
- Precast Concrete Driven pile foundations
- Timber piles
- Composite Piles
1. Steel Driven Pile Foundations
The first type of pile foundation is the steel-driven one. Since this material(steel) is quite readily available, the construction process can be carried through smoothly regardless of the location.
These steel piles(micro piles)can endure the heavy loads bestowed upon by superstructures like bridges. For medium-level loads, other types could be chosen.
There is, however, a disadvantage of the same, and that is, it is vulnerable to rusting and corrosion. But again, since these aren’t directly exposed to oxygen(as they are placed beneath the topmost layer), the chances are low.
These Steel Piles Foundations Have Further Classifications as Well, and Those Are:
1.1. Micro Piles:
Micropiles, which happen to be the first type within steel piles, are steel casinos crammed with concrete cement. The diameter of such micro piles is altered as per the load that will be sitting on them. In certain situations where the load may be more than expected, a much-bolstered cage can be inserted into the pile for extra safety.
The reinforcement cage is also inserted into the pile to increase the pile load-bearing capacity.
1.2.H Pile Driving:
The next type within steel pile foundations is Hot rolled sections, or popularly known as H piles. These hot rolled pieces are welded together to strengthen their capacity, subsequently lasting a while. These, however, are decided on in exceptional cases only. So, you may not find it lying around in any construction area.
1.3. Steel Box Piles:
To achieve the desired form and shape, four steel sheets are welded together to come up with a box shape or hollow box section, both of which can be used for construction purposes.
Once the sheets have been molded into the desired shape, concrete/cement is poured into the inner core part to bump up the lateral firmness and others. This cement filling part cannot be passed over at any cost.
1.4. Screw Piles:
The next type of pile is screw piles, where cast iron screw shape piles are forced into the deep ends using rotary drilling. These, however, aren’t really as popular as the other methods. These are used as per the bearing capacity and nature of the soil.
1.5. Steel Railed Piles:
These are compounded of rails, and to achieve the ultimate form, three rails are welded at the top or the bottom. Again, the reason behind the welding up of two or more sections is to intensify the weight.
The cost of such piles is relatively more minor when set against others. Since we are reusing the old rails people pushed off as old, this could be considered green construction.
2. Precast Concrete Driven Pile Foundations
Up next, we have precast concrete-driven pile foundations. There are two types of such piles, and those are:
- Reinforced precast concrete piles
- Prestressed piles
A few things need to be kept in mind during the construction of the concrete pile driving.
- The first and foremost reason for using such piles is because of their high bending and axial stress attributes.
- Since these are compounded of adequate cover and grade of concrete, they aren’t prone to any sort of deterioration. So, in this sense, they are more durable.
- The minimum cover should be kept at 50mm for the durability requirements.
- Use of Hard and sound aggregates, proper mix design, and compaction of the concrete should be done.
If the composition is not well taken care of, it could lead to deterioration. So when one fixes their sight on such piles, they strengthen them by prestressing, and the minimum cover to be maintained doesn’t fall less than 50mm. Additionally, since these are composed of concrete, there’s no glooming possibility of corrosion, and the cost is less too.
3. Timber Piles
Traditionally, timber piles were used for the construction and erection of structures.
- Over here,hard-driving trees, after their branches are gotten rid of, are used as foundational structures.
- They have the following attributes: They lack the capacity to hold up enormous loads. They cannot stand hard-driving, though they are capable of bearing applied forces and loads.
- Since these are made off of wood, they may very well be the easy targets for many species that feed on wood.
The design load of the timber-driven piles ranges between 150 KN to 250 KN, and the maximum load is about 300 KN.
4. Composite Piles
The purpose of creating such piles was to come up with longer piles that don’t overrun the set cost.
Composite piles, as the name suggests, are composed of different materials instead of sticking to anyone. Also, the selection of the composites is pivoted on the needs and structure.
There are quite a few combinations you can witness and those are:
- Timber piling goes below the ground level, while concrete ones are placed higher than the ground level.
- Pipes crammed with concrete form the lower part of the pile while the other is constructed using concrete cement.
- Up next comes the alternative of precast piles being the upper section.
The main disadvantage of this type of composition is the weakness of the materials at the joints, and there’s barely any method to guarantee it.
Construction of Driven Piles and How They Are Placed
- The structure of such piles isn’t complex. Driven piles, popularly known as precast piles, are readymade elements(timber, steel, cannot, or concrete) dumped deep into the ground or the soil structure of any area by the methods of percussion, vibration, or pressing. This activity is carried out using apropos machinery.
- There are mainly two types of methods in constructing the driven piles: conventional methods and Hammer going ways.
- In the conventional method of constructing the driven piles, the force is applied to the banks by a falling weight and falling into the bank. It should be ensured that the applied load should not exceed more than the capacity of the driven pile.
- The second method is the Hammer-driven pile which is very easy as compared to the conventional way. Generally, the precast piles are constructed with a length of 6m due to transportation issues.
- If any constructor considers this method, they needn’t be worried about the execution, and this doesn’t take much time as they are impervious to local conditions.
Advantages of Driven Piles Foundation
There are several advantages of choosing driven piles over other foundations like:
- The first advantage is that these driven concrete piles can be precast as per the requirements.
- driven concrete piles can be made in advance, as a result of which progress is fastened.
- There’s no extra work that one needs to be involved in post-completion, for the job is extremely neat and today.
- Since most of the activities at the site are handled by machinery, minimal supervision is required.
- You won’t need any extra storage space to keep the elements, machinery, and materials.
- Driven piles are the best alternative in places where drilling holes is strictly prohibited for known and apparent reasons.
- There’s minimal to, and fro movement as everything is at the site so you won’t have to go to any other place as compared to other piling methods.
- Since the equipment and installation methods are given the green signal in terms of quality and time-bound features, it is highly unlikely that something goes wrong.
- These driven piles maintain their shape amidst the installation and post-installation as well.
- The pile is driven into the granular soil, which compacts the adjacent soil mass and will increase the bearing capacity of the pile.
- The involvement of the technical staff in the construction of the driven pile is less.
- There will be no effect of the groundwater table on the construction of the Driven pile.
Disadvantages of Driven Piles Foundation
There are also some disadvantages of driven piles foundations that are as follows.
- The primary disadvantage of this alternative is that it requires advance planning for getting the materials ready and also driving them off to the site.
- The other demerit of such an alternative is the uncertainty to hold up burden during transportation and installation; for this, precast and prestressed concrete piles are required.
- Sometimes, the length cannot be determined just by looking at the site, so in some cases, cutting off the extra parts may be required, which can impede the progress.
- Another disadvantage that we could think of is that these may not be suitable for the places where there is below par drain tile system.
- Another major downside to opting for such foundations is that they are extremely noisy while being installed, so the chances of neighbors knocking on the door are high. Following up, the vibrations caused by the machinery can compound the pre-existing loopholes in any house, and the neighbors can bring the reason upon the piling vibration.
Difference Between the Driven Pile and Bored Pile
The fundamental difference between the two is that the former is pushed straight into the surface structure, and the load bypassing the topmost layer happens through bearing or friction. The latter, however, is typically poured in and the load is, by and large, shifted through the bearing. This is the significant difference between the two, which lies in their method of construction.
The Driven plies are mainly made from the preformed material, with a predetermined shape and size that can be physically inspected before or during the installation process. Whereas the Bored piles are the cast-in-place concrete piles.
The construction equipment required for the construction of the Driven piles is a crane, hammer, piling rig, etc., whereas the equipment required for the construction of the bored piles are drill rig, helper crane and spoil handling, etc.