The top-of-the-range pile.
Frankipfahl NG piles are primarily used where good-quality load-bearing soil types are located deep below the surface and/or where an unusually high load transfer is required. The variety of execution options allow for individual adaptation to a wide variety of subsoil conditions and site locations, ensuring high load-bearing capacities can be achieved.
These piles can be used as perpendicular piles or raking piles at angles of up to 4:1. Frankipfahl NG® piles also feature an enlarged base to improve the absorption of tensile loads.
Edgard Frankignoul originally applied for a patent for what is now a popular pile system all over the world in 1908. This included the fabrication of the complete pile using tamped, earth-moist concrete. The fabrication of shafts using pourable concrete and the characteristic foot dimensions, which have been in common use in Germany since the early 1990s, represent secure and economical improvements to the original concept. To differentiate between the system devised by Edgard Frankignoul and the newer version, we use the name Frankipfahl NG® for the new one, where NG stands for “new generation”.
Frankipfahl NG piles are used in a wide range of soil conditions as foundation elements for a wide range of building types, including:
- Bridge constructions
- Wind energy installations
- Crane runways
- Dock bases
- Industrial buildings
- Heavy-duty surfaces and more
The dimensioning and fabrication of Frankipfahl NG piles is carried out in compliance with Eurocode 7, national standards, DIN 1054, DIN EN 12699, EA guidelines for piles and the recommendations of the Working Group on Piles.
Frankipfahl NG piles are in-situ concrete driven piles with retrievable casing tubes. The tubes are fitted with a waterproof seal at the foot in the form of a plug of dried concrete or gravel sand. A free-falling drive-hammer works inside the casing, striking this plug and driving the tube into the earth. The required ramming force, measured in blows per metre, is an indication of the load-bearing capacity of the soil on the site.
After reaching the desired depth or ramming criteria, the plug is detached and the necessary volume of footing concrete is driven in. The volume required for the expanded pile foot can then be determined on the basis of the firmness of the soil and the pile load expected, using the foot measurement curves. Next, a reinforcement cage is installed, concrete filled in and the casing tube is retracted.
If the soil at the intended casing landing depth does not have sufficient load-bearing capacity, soil improvement measures involving gravel pre-compaction may be undertaken before the pile toe is fabricated. This form of soil improvement consists of pounding in (compacting) gravel both above and below the intended pile casing landing depth. Once the gravel pre-compaction is complete, the pipe is once again rammed in to the intended depth and the previously described fabrication of the Frankipfahl NG pile can begin.
Particularly economically viable.
The specific adaptation of the various designs to suit the soil type and construction site location enables optimum usage with regard to load-bearing capacity and pile length. Frankipfahl NG piles have been used in construction for over 100 years as a result of their sophisticated engineering, high performance standards and outstanding economic viability.
Owing to the contained internal driving method, Frankipfahl NG piles can be fabricated with very low emissions. In suitable boundary conditions, pile foundations can be constructed close to existing buildings using this system.
Full soil displacement means there is no need to extract any soil materials, which prevents any breaking-up of the soil. This type of pile foundation has proven to be particularly successful in construction schemes on contaminated sites.
- Typical load rating up to 6,000kN
- Full soil displacement, no need to transport excavated soil
- May be used on contaminated sites
- Very good resistance and settlement characteristics
- Soil may also be improved by means of gravel pre-compaction
- Reduced pile casing landing depth
- Low noise emissions in comparison to head-driven systems
- Reduced number of piles and foundation dimensions required
- Very economical due to savings in concrete and steel