Ductile Iron Piles
Material and General Information
The Duktus system utilises spun-cast pile sections of ductile iron, featuring a unique conical spigot and socket joint. The material EN-GJS-400-10, from which the piles are made, is a ductile cast iron with spheroidal graphite and has outstanding strength properties.
While in the case of gray cast iron the stress lines are severely focused on the tip of the lamellar graphite (flake) and help crack propagation, in the case of ductile cast iron, the stress lines flow around the spheroidal graphite (nodule) almost undisturbed, thus removing the crack effect.
The standard length of the piles is 5 meters (196.85 in). The modular system enables during the driving process a continuous and very quick assembly of the individual pile sections, as well as a rigid connection guaranteeing both bending and compression strengths.
Installed as End-Bearing or as Skin Friction Pile, Ductile Iron Piles can accommodate a range of different and varying ground conditions.
Technical Specifications and Performances
Tensile strength Rm | 420 MPa (61 ksi) |
0.2% yield strength Rp | 0.2300 MPa (44 ksi) |
Elongation A | min. 10 % |
Modulus of elasticity E | 170.000 MPa (24,656 ksi) |
Compressive strength | 900 MPa (131 ksi) |
Brinell hardness | max. 230 HB |
Density | 7.05 kg/dm3 (0.257 lb/in3) |
Linear thermal expansion | 10.10-6 m/mK |
Pile Sizes
Outside Diameter: | Wall Thickness |
118 mm (4.65 in.) | 7.5 mm (0.30 in) |
118 mm (4.65 in.) | 9.0 mm (0.35 in) |
170 mm (6.69 in.) | 9.0 mm (0.35 in) |
170 mm (6.69 in.) | 10.6 mm (0.42 in) |
Load-bearing Capacities
Maximal permissible internal working load according to Austrian standard ONR 22567 for corrosivity class AS1, depending on wall thickness and concrete strength:
Pile Ø 118 mm (4.65 in.): 520 - 855 kN (117 -192 kip)
Pile Ø 170 mm (6.69 in.): 910 - 1,390 kN (205 - 312 kip)
Achievable pile working loads on site are dependant upon local ground conditions.
Installation and Pile Design
According to the manner in which they develop support (friction or point bearing) the TRM Ductile Iron Piles can be classified in two different ways:
End-Bearing Pile
The TRM system can be installed as conventional prefabricated driven pile. The load-bearing capacity is achieved by transferring the load through very soft soils to an underlying firm stratum. The piles are supported either by bedrock or by extra dense layer of soil at the tip.
Skin Friction Pile
When the pile is driven into soils of fairly uniform consistency and the tip is not seated in a hard layer, the load-bearing capacity is developed by friction along the embedded length, between the pile and the surrounding soil.
By fine-grained cohesive soils the piles are directly supported by friction between ductile iron shaft and surrounding soil (dry driven friction pile). By coarse-grained granular soils the simultaneous drive and grout technique enables to create a grouted annulus and increases the skin friction (grout injection friction pile) between the pile and the surrounding soil.
Many Duktus Ductile Iron Piles carry loads by combination of friction and end-bearing.
A driven pile is a tested pile!
