Virtually every man-made structure of significant size begins with a foundation. In this modern age, when construction types vary from expansive bridges to towering skyscrapers, innovators have had to create foundation types that can withstand tougher conditions than ever before.
One of the support structure types best suited for difficult construction sites is the piling foundation. In this blog, we explain the structure of piling foundations and the reasons why developers choose piling foundations over other foundations.
What Is a Piling Foundation?
In construction, the terms piling and pile refer to structural columns that construction crews use to stabilise other construction elements, primarily deep foundations. While foundations cover horizontal surfaces, pilings run vertically. This perpendicular design provides support similar to the framing inside the walls of a building.
Contractors install pilings by drilling straight down under the area where the foundation will eventually sit. The pilings themselves fit into these bored holes with the topmost portion of each piling remaining aboveground. When workers pour the final foundation, the exposed part of the pilings will integrate into the foundation.
Pilings typically consist of concrete or building metals like steel.
Why Do Construction Companies Use Piling Foundations?
Piling foundations provide a much higher level of stability than simple poured foundations due to their anchoring below the main foundation. You can use piling foundations in almost any building or structure construction project; however, construction companies most often use them for tall, heavy or particularly large projects.
The most basic reason an engineer or contractor chooses a piling foundation is for added support in these oversized projects. For example, towers, bridges and expansive warehouses need the weight distribution and reduced movement a piling foundation offers.
Additionally, piling foundations may be used whenever the ground conditions are not ideal for building. The design of a piling foundation combats the following issues:
- Horizontal pressure: The vertical design of pilings can reduce the effects of horizontal forces on a building. Types of horizontal pressure include seismic activity beneath the building or high winds around a taller building.
- Scouring: Structures built near water must have foundations deep enough not to loosen due to tidal and seasonal water level changes, known as scour. Docks, marine structures and other structures near rivers, lakes and the ocean need piling foundations that reach below scour depth.
- Small building site: The strength of poured foundations comes from their wider dimensions. Buildings with smaller footprints, especially those with multiple stories, need additional support from pilings below.
- Soil erosion: Like scouring, natural soil erosion can expose a foundation and cause shifting. Piling foundations can account for projected erosion and protect against the negative effects on the building.
- Soil expansion: Soil that undergoes cycles of high and low moisture expands and contracts rapidly, straining building foundations. The deep anchor of pilings can minimise the impact of expansion.
- Uplift: Structures built below the water table, such as offshore platforms, experience upward forces, known as uplift, that require deeply set anchors.
- Vibration: Vibration in a building, such as the effects of large turbines, can lead to foundation cracks and instability over time. Piling foundations offset these effects.
- Weak soil: When the top layer of soil at a construction site is particularly prone to collapse or compression, such as in sandy areas, piling foundations are required.
A piling foundation can also provide safer conditions during construction projects with tight timelines when many pieces of large equipment may work simultaneously.
When you’re responsible for the completion of a construction project, your plan begins and relies on a strong foundation.
Consult with your engineers, architects and foundation contractor to determine if a piling foundation is the appropriate way to address potential difficulties at your construction site.