Factors For Selecting The Best Piling On An Industrial Construction Project
November 1, 2015
Deep foundation work requires the right structural integrity. Support piling is a large topic with almost overwhelming variety. The range of piles in common use includes wood piles, prefabricated concrete piles, driven and cast-in-place concrete piles, bored and cast-in-place (non-displacement) piles, steel piles, and specialty piles. This overview will give you a better idea of which piles should be used in different conditions, as well as highlight the necessity of expert analysis from professionals like the STI Group.
Wood piles are the easiest to erect and handle, and they typically have the lowest material and handling costs. Sections are much easier to add or remove than other pile types. The drawbacks to wood are that they cannot bear loads as heavy as the others, the wood is susceptible to water damage and rot, the piles are difficult to splice, and they are vulnerable to borers.
Prefabricated Concrete Piles
Concrete has many advantages over wood. It can hold heavier loads, and it will never rot. Prefabricated concrete adds some more specific advantages. The quality of the concrete can be checked before the pile is driven, reducing potential expenses. These piles are stable in softer soils and clays and are unaffected by groundwater. They can also be driven in long lengths, making them ideal for marine or water structures. Prefabricated concrete has disadvantages as well. It can be difficult to cut, and it can have heavy impact on the site soil, sometimes causing large amounts of soil displacement. Concrete is susceptible to damage during driving, meaning replacement costs can be incurred during construction. These piles cannot be driven with very large diameters, and they require sufficient headroom for driving. Finally, they can have problems with vibration.
Driven and Cast-in-Place Concrete Piles
These are concrete piles that are not necessarily prefabricated. The have a distinct advantage that they can be either permanently or temporarily cast. Like other concrete piles, they can be inspected before installation. They can also easily be cut or extended. They are lower cost than most pile types and have a low noise level. These piles can also be cast before excavation. This allows them to be structured to prevent groundwater damage, and driving damage is not an issue.
Concrete piles have disadvantages to consider as well. If they are not prefabricated, then they are at much higher risk for tension damage. With cast piles, the concrete cannot be inspected after construction. These piles are very difficult to add to after casting, and they can cause significant ground displacement.
These piles involve the removing of soil. This creates a unique advantage in that the removed soil can be sampled and tested. These are typically cast-in-place piles, which means the usual structural advantages of concrete are available. Additionally, they can be constructed with larger diameters than other concrete piles, and they require minimal headroom for driving. These piles are not at risk to driving damage, enabling a wider use of concrete materials for mixing. They also afford varying pile length.
The cons of non-displacement piles begin with the inability to inspect them after construction. In some cases, pressure can wash out the cement. They cannot be extended above ground level in river and marine structures. Removing soil can loosen surrounding earth, requiring additional stabilizing methods before the piles are installed. The piles can also move enough soil to cause settlement among nearby structures.
Steel is relatively easy to handle and is very customizable in shape and function. Steel piles offer the most tensile strength which allows them to be driven through very dense layers. Pipe piles can also be implemented to minimize soil displacement. Steel piles can bear the heaviest loads, can endure the heaviest driving and can be used in the most diverse ground conditions. They are also among the easiest to add to after driving.
Downsides to steel piles include corrosion, water damage and cost. They are among the most expensive piles and are very vulnerable to water exposure. They are also the most likely to deviate during driving, meaning that replacement costs may be incurred.
These are the piles you use when none of the others will satisfy requirements cut it. They can be made from any of the materials of the other types of piles, depending on your specific needs. The advantages of specialty piles is that they can do the jobs no other piles complete. Their drawbacks are usually related to cost. Special design and driving methods are often more expensive than standard options.
The large variety of piling options can be daunting. However, In most cases selecting the right pile can be simplified by understanding the pros and cons of each and being aware of project priorities. Having the right expertise when designing and driving piles is the only way to ensure safe, efficient and cost effective construction. STI Group is extremely experienced in deep foundation work and we can help our clients select the best piles for their deep foundation projects.