By Simon Griffiths 60R • 76R • 89R • ABC Anchors • Foundation Solutions • Screw Piles • • • • • • • • • • 0 Comments

Screw Piles

Screw Pile Capacities and Installation Equipment

60Rrangeb 76RRangeb 89R-39336b
Screw Pile Range 60R 76R 89R
Torque Head Model 400H 500X 1600X                       700H 2500X
400H 500X_XG 1800X 2500XGb
Max Torque 4kNm 5kNm 16kNm                     7kNm 22.5kNm
Machine Type Hand-held Excavator Excavator               Hand-held Excavator
Ultimate Pile capacity
(un-factored) torque		 120kN 150kN 450kN                      196kN 562kN
Safe Working Load
(2.5 FOS)		 48kN 60kN 180kN                      78kN 225kN
Specification Sheet
(PDF)

Un-factored Load - A Maximum load that the Pile will take before deflection exceeds standard limits.

FOS - Factor of Safety - is the ratio between the un-factored load and the working load

Safe Working Load -The actual load the pile is taking when the building is in place

All machines offer torque read outs, allowing the pile capacity to be calculated instantly.

Screw Pile Specifications

SPECIFICATION DEFINITION 60R 76R 89R
Shaft Diameter Diameter of the screw pile shaft excluding helices 60mm 76mm 89mm
Wall Thickness Thickness of the screw pile tube wall 6.35mm 9.5mm 9.5mm
Torque Limit The ability of the pile to transmit torque is always the limiting factor. This is therefore the ultimate practical pile install torque capacity. 4kNm 16kNm 22.5kNm
Empirical torque factor KtKt m-1 The “Empirical Torque Factor” expressed in metric units when torque is measured in kNm and force in kN. Its value decreases as pile diameter and helix plate thickness increases. This is due to a combination of skin friction and the energy needed to displace the soil. 30m-1 28m-1 25m-1
Tube Specification BSEN 10297

E355 HFS

 BSEN 10297

E355 HFS

 BSEN 10297

E355 HFS
Helix Specification BSEN 10025

S275

 BSEN 10025

S275

 BSEN 10025

S275
Fasteners Specification Metric M16 GR8.8 Metric M20 GR8.8 Metric M22 GR8.8

Pile Life/Corrosion

In most conditions, provided the top 2 metres are galvanised the pile life will be in excess of 100years. Where the soil resistivity is less than 10 Ohm– further steps must be taken. This means salt water, wet peat and where soils are subject to saturation. For more information and literature please contact us.

The estimated life is based on the assumption that a loss of 40% in thickness is acceptable without adverse effect on structural integrity. The atmospheric exposed areas of the piles are coated with high build zinc rich coating system or galvanised. There is a safety factor of x2 included for the anode design to take account of variances in corrosion conditions and ground resistivity.

Ground Resistivity(Ohm-m) Corrosion rate based on Uhlig data mm/yr Estimates life with corrosion protection (years) Corrosion protection methods, required for top 2m section of Pile. (Min 9.35mm wall thickness) Estimated life with additional corrosion protection* (years)
Less than 5 0.1-0.2 18-37 Zinc rich coating
4 x 20kg galvanic zinc bracelet		 100
5-10 0.033 80+ Zinc rich coating
4 x 20kg galvanic zinc bracelet		 100+
10-50 0.025 100 Zinc rich coating 100+
50-100 0.018 100+ n/a 100+
Greater than 100 0.014 100+ n/a 100+