This document discusses the use of helical anchors as foundations for transmission line towers in Brazil. It notes that Brazil is investing $20 billion USD by 2018 to expand its transmission network by 37,600 km. One project discussed is the Belo Monte transmission line, which will be up to 2,500 km long and carry 800kV. Soil tests were conducted to determine appropriate foundation solutions. Helical piles between 3.5-4.5 inches in diameter are commonly used in Brazil for compression and tension loads on guy, central, and self-supported towers. Dimensioning of helical piles considers soil properties. Field tests demonstrated helical piles can successfully support guyed and self-supported towers. They provide advantages over conventional

1. The Use of Helical Anchors as a
Foundation Solution to Build
Transmission Line Towers in Brazil
Danilo Policastro P.E.
Latam Civil Application Engineer
MacLean Power Systems
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2. Brazil Transmission Market Overview
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INVESTMENT UNTIL 2018
R$ 70 BILLION
US$ 20 BILLION
37.600 KM
INVESTMENT ALREADY
CONTRACTED TO HAPPEN
IN 2015-2018
R$ 22 BILLION
US$ 6 BILLION
SOURCE: EPE/MME/BRAZIL

3. Belo Monte – Transmission Line
Characteristics
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4. Belo Monte – Hydro Generation
• 3 types of guying
towers
• Up to 80 metric tons
(177k lb) of load per
guy anchor
• 800kV line
• Up to 2500km of line
double circuit DC
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5. Soil tests
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6. Helical Piles Families Used in
Brazil and General Specifications
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PIPES 3.5”&4.5” OD RCS 1.75”&2.0”
COMPRESSION & TENSION
LOADS
TENSION LOADS
GUY / CENTRAL TOWER /
SELF SUPPORTED TOWER
GUY ANCHORS

7. Helical Piles – Dimensioning
Overview
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QHELIX=Ah . [(c . Nc) + (q x Nq)]
Cohesive soils:
clay
Non-cohesive
soils: sand
QPILE = ∑ QHELIXES
PRODUCTIVITY:
PITCH = 3”
8 CYCLES
PER MINUTE
24”/MIN
0.6M/MIN
40MIN PER
ANCHOR

8. Helical Piles – Safety Factors
Considerations
• Brazil:
• Self supported towers: 1.5
• Central foundation: 1.3
• Guy: 1.1
• Latin America:
• 2 ~ 3 all foundations
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9. Other Foundation Methods for
Transmission Lines
• Auger Cast
• Drilled Shafts
• Spread Footing
• Precast piles
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10. Helical Piles x Conventional
Solutions (EPC’s View)
• 3 people per team
instalation
• 2 towers per day of
instalation
• After installed is ready
to receive the load
• High quality control
• Cost: $$
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11. Helical Piles x Conventional
Solutions (EPC’s View)
• More than 10 people per team
• 1 tower each 2 days of construction
• Need to wait 14 days to start putting load
• Quality control not always reflects what happen
• Cost: $$$$
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12. Instalation
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• Location: Monte
Carmelo (MG)

13. Field tests for helical piles
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14. Field tests for helical piles
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15. Helical Piles for Guying Towers
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16. Helical Piles for Self Supported
Towers
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17. Danilo Policastro
Latam Civil Application Engineer
dpolicastro@macleanpower.com
+55 (11) 99809-3933
Skype: danilo.policastro
MacLean Power Systems
www.macleandixie.com
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