In the field of construction, piles, and piers are two types of deep foundations that are commonly used in the construction of buildings. If you are going to construct a home on a pile foundation, you will need to know the difference between pile and pier foundation.
It is important for a foundation engineer to know the differences between these two types of deep foundations in order to choose between them when installing a foundation. Here in this article, we are going to try to explain to you the difference between pile and pier foundation.
What Is Pile?
A pile is basically a column that is embedded beneath the subsoil strata in order to transmit the structural load to the lower level of the subsoil strata in the form of a load transmission system. The Pile foundation is a type of deep foundation whose vertical members are used to transfer the loads from the top of the pile to the bottom stratum underneath it.
In the case of pile foundations, the loads are transferred via the vertical member. There are many different materials that can be used to make piles such as wood, concrete, and steel.
As a general rule, pile foundations are built at a greater depth than other types of foundations. As a rule of thumb, pile foundations are used in the construction of megastructures such as bridges and flyovers.
Types Of Pile?
There are a number of types of pile foundations, and they include the following:
- End bearing piles foundation.
- Compaction pile foundation.
- Anchor pile foundation.
- Friction pile foundation.
- Dolphin and fender piles foundation.
- Tension or uplift piles foundation.
- Sheet and batter piles foundation.
- Combined end bearing and friction piles foundation.
Condition to Use Pile Foundation
Basically, if you want to know the difference between pile and pier foundation get to know that the pile foundations are used where there is a very unstable and low bearing soil strata up to a definite layer at the base of the ground strata.
In cases where a foundation is unable to transmit the safe load directly below the foot of the substructure to the ground without exceeding the soil’s bearing capacity, pile foundations are usually used.
Due to its frictional bearing mechanism, the pile’s foundation is capable of gradually transferring the load throughout the ground strata of the substructure.
Additionally, pile foundations are considered a technique for improving soil-bearing capacity. Additionally, they can be used to prevent excessive seepage through the ground strata (especially sheet piles).
Piles are particularly useful in areas where the groundwater table is high. So, in most civil construction projects, such as dams, reservoirs, bridges, etc., piles are installed to ensure a stable base for the structure even in high water table conditions.
When driven piles are embedded over loose soil, the soil can even be compacted and its bearing capacity reduced. Further, friction piles are used for structures that may experience both uplift and thrust pressure.
What Is Pier Foundation?
A pier is a raised structure that supports a well-based foundation. Pier foundations consist of large diameter cylinder columns used to support the superstructure load and transfer it to the soil beneath. In general, pier foundations are constructed at a shallow depth.
The pier foundation is primarily a type of pile foundation that has a higher cross-section area and a lesser depth than pile foundations. Due to their large cross-sectional area, they are constructed by drilling boreholes and casting in situ or installing precast piers.
Due to their very low frictional bearing capacity, their primary means of transferring load to the ground is through end bearings. Piles are similar to shallow foundations, but they are dug deeper until they reach the hard strata of soil or bedrock, thereby transferring the load without exceeding the safe bearing capacity.
Having a large cross-sectional area, the pier foundations are used separately, so the pier cap is applied to each pier above which the column’s footrests.
Types Of Pier Foundation?
In the following list, we will discuss the different types of pier foundations:
- Drilled caissons pier foundation.
- Drilled concrete pier foundation.
- Concrete in steel shell pier foundation.
- Concrete and steel pier foundation.
Condition to Use Pier Foundation
Pier foundations transfer their load through end bearing mechanisms. Therefore, they can only be used when the ground strata do not have a good bearing capacity only up to the surface, but consist of either a hard rock bed or a good bearing capacity soil layer that reaches a certain depth below the surface.
For compacted stiff soils and rocky bases where drilling holes are too deep for piles, piers are more convenient. When such conditions exist, they are more effective than pile foundations. In general, they have a flat bottom at the end of the ream so that the load intensity at the bottom layer of the pier-soil interface is decreased.
As opposed to normal residential and commercial buildings with good ground strata at a certain convenient depth, pier foundations are useful for structures with relatively high structural loads.
There are times when the pier is also suitable for loading over pile caps and is therefore referred to as a post foundation. When there is a bridge that is too high from the ground level to the top of the bridge, this is usually very useful. It is therefore up to the depth of the strata just below the ground level that the piles are brought, and above these piles are constructed the piers.
Since you are eager to know what the difference is What is the difference between pile foundation and pier foundation, I am going to answer it for you. Let’s have a look at this together. In this lesson, we will learn about Piers vs. Piles or the difference between pile and pier foundation.
Difference Between Pile and Pier Foundation
Below are some of the main differences between pier and pile foundations. It’s time to look at Piles vs. Piers.
| Description | Pile Foundation | Pier Foundation |
| Load Bearing and Transfer Mechanism | Due to their large cross-sectional area, they are preferred to be installed by drilling the boreholes in order to install them. | In general, it is applied directly to the bottom end of the foundation using end-bearing mechanisms. |
| Uplift Force With Standing | It is due to the frictional driving of piles that they have an excellent frictional bearing mechanism. When piles are being pushed downwards, an upward frictional resistance force is created, and when piles are being thrust upwards, this frictional resistance changes to a downward force. | It is not able to withstand the uplift forces due to its mechanism and its own weight as well. |
| Horizontal Forces | It is designed with an inclination so as to overpower horizontal forces in such a way. | A horizontal load only needs to be countered by the flexural property, in order to maintain the retaining capacity. |
| Sizes | It has a very small cross-section and a higher depth. Its diameter ranges from 0.3 meters to 2 meters, and its depth ranges from 20 meters to 100 meters. | Comparatively larger cross sections, with a diameter of 0.6 m to 3 m and a depth of 5 m to 20 m. |
| Installation | Installation of these pipes can be done in two ways, either by ramming & hammering them into the ground or by casting them into boreholes. | Generally, these are suitable and economical when the hard soil strata or rock beds are exposed at a depth of 5-10 meters. In areas where the groundwater table is high, they are not recommended. |
| Suitability | Generally, they are very suitable for use where the soil has a very low bearing capacity to the depth of a great deal. As a result, they are suitable for areas with a high groundwater table. | The piles are of small diameter and are often spaced closely together. Since the use of a single pile is very limited, the piles are usually used as a group of piles monolithically connected by pile caps. The minimum spacing is 2.5d for end-bearing piles and 3d for frictional piles. The maximum spacing ranges from 6d to 8d (d is the diameter of the pile). |
| Spacing | Compared to piles, they are used in a single way and are arranged at greater spacings. In the case of single piers, a single-pier cap is provided. As required, the spacing between each unit is between 5 and 10 feet. | They are considered to be techniques for improving soil-bearing capacity. |
| Perspective | They are considered to be techniques for improving soil bearing capacity. | The members of the structure are considered structural members. |
| Economy | Pile foundations are more expensive than other types of foundations. Consequently, they are used only when the construction of a project is large and complex. | The cost of pier foundations is comparatively lower than that of pile foundations. |
Final Words
As I conclude this article on the “difference between pile and pier foundation”, I hope that you will find this information useful and learn the difference between pile and pier foundation. The terms “piles” and “piers” are very similar in their meaning, and they are often referred to synonymously, but there are a few key differences in terms of their sizes and materials.
Frequently Asked Questions
What Is Pile In Civil?
As a part of building construction, a pile is a post-like support member that has been used since prehistoric times. To support a structure, piles made of timber, steel, or concrete may be driven into the ground; bridge piers, for example, may be supported on groups of large-diameter piles, as in modern civil engineering.
Pier vs Pile
There are so many difference between pile and pier foundation. The piles are made up of vertical pillars, which are made out of concrete or steel. It is common for piers to be the same size and shape as each other. In soils lacking firm strata, such as bedrock, piles are often used to prevent soil from settling. It is typically the case that piles are used to support greater loads, such as the weight of highway bridges.