Support of Transmission Line Structures Using HELICAL ANCHORS and PILES

111 Pages·2014·19.65 MB·English

by  Nick Farkas

Support of
Transmission Line
Structures Using
HELICAL ANCHORS
and PILES
MITCHELL SCREW PILE & MOORING
Maplin Sands Lighthouse -
1838
1st Recorded use was by
Alexander Mitchell (1780-1868)
in 1836 for Moorings and was
then applied by Mitchell to
Maplin Sands Lighthouse in
England in 1838
U.K. Patent No. 6446 – 1833
(renewed 1847)

U.S. Patent No. 3986 - April 1, 1845
Advantages – Screw Anchors/Piles
• Quick, Easy Turnkey
Installation
• Immediate Loading
• Small Installation Equipment
• Pre-Engineered System
• Easily Field Modified
• Torque to Capacity Correlation
• Install in Any Weather
• Solution for:
– Restricted Access Sites
– High Water Table
– Weak Surface Soils
• Environmentally Friendly
– No Vibration
– No spoils to Remove
– No Concrete
Helical Piles

Why Use Helical
Piles?
1. Economically handle the loads
• Uplift
• Compression
• Shear and overturning
moment due to wind loads

2. Resists Up-Heave due to:
• Ground Freeze
• Expansive Soils

®
3. Environmental Benefits:
• No excavation
• Eco system simplified permitting
• Removable, reuse or recycle
• Quiet installation
• Soil compaction without changing
mean elevation

4. Fast, simple, low cost installation
• Standard excavation equipment
• Inexpensive Tooling
• High Production rates
100+ piles/day/crew
• Load the piles immediately
• Minimal training needed
(a specialty contractor is
not required)

®
Square Shaft
Helical
Products
CHANCE SCREW ANCHORS
SS5,SS150, SS175, SS200 &
SS225
SQUARE SHAFT
356 mm
36
3 m
305 mm
254 mm
203 mm
Lead Section Helical Extension Extension
CHANCE® Helical Anchors & Piles
Tension/Compression
SQUARE SHAFT
Torsion & Tension Ratings
SS125 SS5 SS150 SS175 SS200 SS225
4,000 ft-lb 5,500 ft-lb 7,000 ft-lb 10,500 ft-lb 16,000 ft-lb 23,000 ft-lb
50 kip 70 kip 70 kip 100 kip 150 kip 200 kip
22700 kgf 31750 kgf 31750 kgf 45400 kgf 68000 kgf 90700 kgf
CHANCE® Helical Anchors & Piles
Tension/Compression
Shaft Grade – 70,000 psi (483 mPA) & 90,000 psi (621 mPa) minimum
Helix Grade – 50,000 psi (345 mPa) & 80,000 psi (552 mPa)
Square Shaft Series Product Ratings
Product Torque Ultimate Tension
Series Rating ft-lb Tension Capacity in
(N-m) Strength* Soil**
lb (metric lb (metric
ton) ton)
SS5 5500 (7500) 70000 (32) 55000 (25)
SS150 7000 (9500) 70000 (32) 70000 (32)
SS175 10500 100000 (45) 100000 (45)#
(14240)
SS200 16000 150000 (68) 150000 (68)#
(21700)
SS225 23000 200000 (91) 200000 (91)#
(31200)
* Based on Mechanical Strength of Coupling.
** Based on Shaft Torque Rating – Tension/Compression = Shaft Torque Rating x K
t
“Default “ K for the SS Series = 10 ft-1
t
# Limited by Mechanical Strength of Coupling
Pipe Shaft
Helical
Products
CHANCE SCREW PILES
RS2875, RS3500,
RS4500,RS8625, RS10750