The Top 6 Techniques for Casting Reinforced Concrete Piles
Precast piles can be transported to the construction site or constructed at the project site. Cast in situ piles are constructed by drilling a borehole, installing reinforcement cages, and placing concrete.
Reinforced Pile Construction Techniques
Rotary Drilling While Supporting by Hydrostatic Pressure
The borehole is excavated by rotary drilling, but the wall is supported by bentonite solution or polymer slurry. At the beginning of the excavation, a short length casing guides the excavator, and the excavation spoil is removed with a bucket.
There is no limit to the size or depth of the piles, as well as the diameter and depth of the piles, with this construction method. Drilling is vibration free, and the pile could be drilled to a depth of 40 meters or deeper, and its diameter could range from 40 cm to 240 cm.
Rotary Drilling While Supporting by Casting
Boreholes are excavated using rotary drilling, and their sides are supported by casings. The casing is driven into the ground with a diameter slightly larger than the pile diameter using a rotary drive.
Piles with larger diameters and deeper depths, casing oscillators can be used. There is no limit to the type of soil or constrictions of the construction site that this technique will work on.
It does not produce vibrations during drilling is an outstanding advantage. A range of 60 cm to 180 cm is required in diameter for the pile. It is possible to reach a depth of 40 m at the deepest point of the pile.
Rotary Drilling While using Two Rotary Head
Construction machinery produces no vibration, which is a desirable feature, especially in urban areas. With counter rotating twin drives, contractors can simultaneously drill and install casing with continuous flight augers. The system can be installed against existing walls on constrained sites and is suitable for all soil types.
A pile with a diameter of 63 cm to 88 cm reaches a depth of around 15 m. This technique involves pouring concrete while lifting the auger. As a result, the reinforcement cage is placed after the concrete has been placed. The reinforcement cage must be placed by vibration or driven force.
Augar Cast in Situ Pile
Boreholes are drilled, soil is lifted, and concrete is poured while the continuous auger is moving up. Therefore, hydrostatic pressure and casing are not needed to prevent borehole wall damage.
Construction sites with limited space can benefit from Auger cast-in-situ piles. This is a vibration free facility that can be accessed easily to a depth of about 18 meters. Auger cast in situ piles range in diameter from 40 cm to 100 cm.
Because it does not affect its surroundings, grab construction requires a minimum distance from existing structures. Construction of grab piles involves a crawler crane and a casing oscillator.
There is a high demand for casing technology in grab construction for certain soil types, like sand and gravel. A chisel can break boulders and bedrock in locations where it is affordable and feasible. Approximately 50 meters deep and 62 cm in diameter, the pile has a 62 to 200 cm diameter.
Pile Construction Displacement
A displacement pile is a unique method where the pile construction method can be used in contaminated soil to prevent drill spoil disposal. Construction sites with soft soil and tight spaces are also suitable for it.
Comparatively to auger cast in-situ piles, displacement piles have a high bearing capacity, avoid drilling spoil, and reduce concrete utilization. The pile depth is around 34 m, and the drilling diameters are 42 cm, 51 cm, and 61 cm.
To learn more, watch the following video tutorial.
Video Source: Proud to be a Civil Engineer
Wrapping it Up
It is recommended to use a pile foundation when a structural load is large, and a thick and weak soil layer is present below. By transferring load from a weak soil to a stiff layer, it can support a substantial superstructure.
Rings on the outer and inner sides of the pile cage provide vertical reinforcement. Piles can be reinforced vertically, horizontally, or both with Outer Ring Reinforcement & Inner Ring Reinforcement.