national wood pole standards44 circumference3effect mg/l= .000264 x fiber strength x circumference 3...

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• Nelson G. Bingel III• ASC O5 Chairman• NESC Chairman

National Wood Pole Standards

President(678) [email protected]

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Benefits of Wood as a Utility Pole Material

• Long-Life Span• ~45 years national average without remedial treatment

• Lowest cost• Both initial and full life-cycle costs

• Proven Performance • “Go to” overhead line construction material since the

early 1900’s

• Climb-ability• Ability to service attachments without heavy equipment

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• Supply Chain is Proven• Even in natural disaster events where demand is high, the wood

pole industry has provided poles in required timeline.

• Beneficial Physical Properties• Good insulator, resilience to wind and mechanical impacts

• Easy Maintenance and Modification in service

• “Green”• a treated wood pole has a reduced environmental impact when

compared to other utility pole materials.• A renewable and plentiful resource

“10 Features Often Overlooked About the Extraordinary Wood Pole.” North American Wood Pole Council. www.woodpoles.org

Benefits of Wood as a Utility Pole Material

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ANSI

American National Standards Institute

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ANSI


ANSI accredits the procedures of standards developing organizations

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ANSI



National consensus standards

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ANSI



National consensus standards

Openness, balance, consensus and due process

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American Standards Committee O5 – ASC O5

American Standards Committee O5

USERS

PRODUCERS

GENERAL INTEREST


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Accredited Standards Committee O5:

Standards for Wood Utility Structures

• Secretariat: AWPA

• Revised: 5 year cycle

• Founded in 1924


ASC O5 NESC

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ASC O5 Standards

O5.4 - 2009 Naturally Durable Hardwood Poles

O5.5 - 2010 Wood Ground Wire Moulding

O5.6 - 2010 Solid Sawn Naturally Durable Hardwood Crossarms & Braces

O5.TR.01-2004 Photographic Manual of Wood Pole Characteristics

Glu-Lam CrossarmsPoles

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http://asco5.org/standards/

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http://asco5.org/standards/

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Scope

Single Pole

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Scope

Single Pole

Simple Cantilever

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Scope

Single Pole

Simple Cantilever

Transverse

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Scope

Single Pole

Simple Cantilever

Transverse

Groundline

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Maximum Stress Point

Solid, Round, Tapered, Cantilever

Load(Wind Force on Wires, Equip., etc.)

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Max Stress @ 1.5 Diameter Load Point



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Distribution Usually Groundline


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Distribution Usually Groundline


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ANSI O5.1 – Wood Poles

WoodQuality

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ANSI O5.1 – Wood Poles

WoodQuality

ClassLoads

PoleDimensions

FiberStrength

23

Wood Quality

• Allowable knots

24

• Sweep

Wood Quality

25

• Growth Rings

Wood Quality

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Pole Marking & Code Letters

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Pole Marking & Code Letters

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Transverse Wind Loads

Ice

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Class Loads

2 ft Lc

HorizontalClass Load (lb)10 3709 7407 1,2006 1,5005 1,9004 2,4003 3,0002 3,7001 4,500

H1 5,400H2 6,400H3 7,500H4 8,700H5 10,000H6 11,400

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General Class Load Applications

2 ft Lc

HorizontalClass Load (lb)10 3709 7407 1,2006 1,5005 1,9004 2,4003 3,0002 3,7001 4,500

H1 5,400H2 6,400H3 7,500H4 8,700H5 10,000H6 11,400

Telecom Only Poles

Distribution

Transmission

General Industry Use

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Strengths are Average Values

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Wood vs. Steel VariabilityASCE Manual and Reports on Engineering Practice No. 141

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Lc2 ft

Class 1 4,500 lbClass 2 3,700 lbClass 3 3,000 lbClass 4 2,400 lbClass 5 1,900 lb

Applied Bending Load

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Lc

D

2 ft



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Lc

D

2 ft


Applied Bending Load =Lc x D (ft-lb)


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L x D = Bending Moment (ft-lb)

76,800 ft-lb

2400 lb

32 ft

40 ft Class 4

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L x D = Bending Moment (ft-lb)

76,800 ft-lb

2400 lb

32 ft

40 ft Class 4

41 ft

98,400 ft-lb

2400 lb

50 ft Class 4

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Lc

Fiber Strength

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Lc

Compression(psi)

Tension(psi)

Fiber Strength

40

Lc

Fiber Strength

Fiber Strength

Compression(psi)

Tension(psi)

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Lc

Compression(psi)

Tension(psi) Fiber Strength

Bending Capacity =k x fiber strength x C3 (ft-lb)

Fiber Strength

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Circumference3 Effect

MG/L = .000264 x Fiber Stress x Circumference 3

26”34”

37,120 ft-lb83,010 ft-lb

Circumference Increase - 30%

Bending Capacity Increase - 123%

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MG/L = .000264 x Fiber Strength x Circumference 3

26”34”

37,120 ft-lb83,010 ft-lb



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MG/L = .000264 x Fiber Strength x Circumference 3

26”34”

37,120 ft-lb83,010 ft-lb



80-90% Pole’s Bending Strength

In The Outer 2-3” Of Shell!

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Table 1 – Designated Fiber Strength

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Group AAir Seasoning

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Group BBoulton Drying

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Group CSteam Conditioning

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Group CSteam Conditioning

Group DKiln Drying

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Southern Yellow Pine 8,000 psi

Douglas fir 8,000 psi

Western red cedar 6,000 psi


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Pole Species

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Pole Species

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Pole Species

Distribution:Southern Yellow Pine

Transmission:Douglas fir

Western red cedarSouthern Pine

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Pole Species

Distribution:Southern Yellow Pine

Transmission:Douglas fir

Western red cedarSouthern Pine

Distribution:Douglas fir

TransmissionDouglas fir

Western red cedar

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1) The effects of conditioning on fiber strength have been accounted for in the Table 1 values provided that conditioning was performed within the limits herein prescribed.


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4) The designated fiber strength represents a mean, groundline, fiber strength value with a coefficient of variation equal to 0.20.


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Through-boring

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Oregon State University-Through-Boring Project-

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Through-boring

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5) Where Douglas-fir (coastal or Interior North) are through-bored prior to treatment, to account for the process, the designated fiber strength shall be reduced 5% to 7600 psi.


4) The designated fiber strength represents a mean, groundline, fiber strength value with a coefficient of variation equal to 0.20.


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2017 Table 1 added MOE

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1) The fiber strength and MOE values in Table 1 apply to wood utility poles meeting this standard. The effects of conditioning on fiber strength and MOE have been accounted for ……..

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1) The fiber strength and MOE values in Table 1 apply to wood utility poles meeting this standard. The effects of conditioning on fiber strength and MOE have been accounted for ……..

7) The Modulus of Elasticity (MOE) represents a mean value.

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TIP

6ft

G/L

Circumference Dimensions

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TIP

6ft

G/L


Circumference Dimensions

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Circumference Dimension Tables

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72


1) The figures in this column are not recommended embedment depths; rather, these values are intended for use only when a definition of groundline is necessary in order to apply requirements relating to scars, straightness, etc.

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Annex B: Groundline Stresses

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Minimum circumferences specified at 6 feet from the butt

Were calculated so each species in a given class

Can support the class horizontal load applied 2 ft from the tip

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76

77







77

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Pole Dimension Table

(in)

Southern Pine and Douglas Fir

78

79


(in)


79

80


(in)


80

81


(in)


81

Applied Bending Load= Class Load * Distance

76,800 ft-lbs= 2,400 lbs* 32ft

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(in)


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Applied Bending Load= Class Load * Distance

Bending Capacity =k x fiber strength x C3

79,401 ft-lbs=.000264 x 8000x 33.53

76,800 ft-lbs= 2,400 lbs* 32ft

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40 ft Class 4 Poles

Douglas fir(8000 psi)

Western Red Cedar (6000 psi)

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40 ft Class 4 Poles



2400 lb

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40 ft Class 4 Poles


36 1/2”


33 1/2”

2400 lb

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Note 7

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Average circumference tapersin the groundline zone of a pole

Note 7

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ANSI O5.1 Summary

2 ft Lc

BendingCapacity = k x fiber strength x C3 (ft-lb)

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ANSI O5.1 Summary

2 ft Lc


Lc

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ANSI O5.1 Summary

2 ft Lc


All SpeciesSame Length & ClassSimilar Load Capacity

Lc

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ANSI O5.1 Summary

2 ft Lc



Lc

= k x fiber strength x C3 (ft-lb)

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ANSI O5.1 Summary

2 ft Lc



Lc

= k x fiber strength x C3 (ft-lb)= k x fiber strength x C3 (ft-lb)

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Fiber Strength Values

1965 Publication

Forest Products Lab

Fiber Strength Derivation

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FPL 39 Table 4Final Adopted Fiber Strengths

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FPL 39 Table 4Final Adopted Fiber Strengths

Near 5% Lower Exclusion Limit

Of Actual Average Bending Strength

Of Three Pole Groups

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Newer Test Data That Was Adjusted to Align with FPL 39

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Annex C – Poles <50 ft

9797

Newer Test Data That Was Adjusted to Align with FPL 39Annex C – Poles 50 ft and longer

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All Adjusted Full Scale Break Tests

ASTM

EPRI

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All Adjusted Full Scale Break Tests

ASTM

EPRI

No Changeto

Previous Fiber Strengths

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Annex AFiber Stress Height Effect

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101

Annex AFiber Stress Height Effect

Round timbers are known to decrease in ultimate unit strength

with height above ground.

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Actual Pole Dimensions

CA

TX

NY

FL

IL

PA

OH

MI

NJ

GA

NC

VA

MA

IN

WA

TN

MO

WI

MD

AZ

MN

LA

AL

CO

KY

SCOK

OR

CT

IA

MS

KS

AR

UTNV

NM

WV

NE

ID

ME

NH

RI

MT

DE

SD

ND

VT

DC

WY

Sample Locations Coastal Douglas Fir (8)

Coastal DF & Western Red (3)

Northern Red Pine (3)

Southern Yellow Pine (16)

Western Red Cedar (5)

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• Coastal Douglas fir 6,997 poles9 Producers; 11 Locations

• Southern Yellow Pine 6,634 poles11 Producers; 16 Locations

• Western Red Cedar 6,982 poles5 Producers; 9 Locations

• Northern Red Pine 2,266 poles2 Producers; 4 Locations

Pole Circumference Data

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• Coastal Douglas fir 6,997 poles9 Producers; 11 Locations

• Southern Yellow Pine 6,634 poles11 Producers; 16 Locations

• Western Red Cedar 6,982 poles5 Producers; 9 Locations

• Northern Red Pine 2,266 poles2 Producers; 4 Locations

Grand Total 22,859 poles

Pole Circumference Data

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Fiber Stress Height Effect (FSHE)

• Tips average 1.5 to 2 classes larger

• Poles 55 ft and shorter• Maximum stress is usually at G/L– FSHE not applied• Maximum stress for guyed poles may be above G/L– Oversize offsets fiber stress height effect

• Poles 60 ft and taller• If maximum stress is at the G/L, no FSHE• If maximum stress is above ground, tables for

reduction

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O5.4 - 2009 Naturally Durable Hardwood Poles

O5.5 - 2010 Wood Ground Wire Moulding

O5.6 - 2010 Solid Sawn Naturally Durable Hardwood Crossarms & Braces

O5.TR.01-2004 Photographic Manual of Wood Pole Characteristics

Glu-Lam CrossarmsPoles

ASC O5 Standards http://asco5.org/standards/

107

Accredited Standards Committee O5:

Standards for Wood Utility Structures

• Secretariat: AWPA


• Founded in 1924


ASC O5 NESC

108

National Overhead Line Standard

ANSI C2:

National Electrical Safety Code

• Secretariat: IEEE (Institute of Electrical and Electronics Engineers)


• Established in 1915

NESC

109

NESC Committee Structure

Chairman Vice Chair Secretary-IEEE

25 – 35 MembersMainCommittee

ExecutiveSubcommittee

TechnicalSubcommittees

Chairman Secretary

6 - 10 Members

Chairman Secretary

SC 1 – Coordination; Sections 1,2,3SC 2 – GroundingSC 3 – SubstationsSC 4 – Overhead Lines – ClearancesSC 5 – Overhead Lines – Strength & LoadingSC 7 – Underground LinesSC 8 – Work Rules

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Purpose of the NESC

111

B. NESC rules contain the basic provisions, under specified conditions, that are considered necessary for the safeguarding of:1. The Public2. Utility workers (employees and contractors), and3. Utility facilities

C. This code is not intended as a design specification or asan instruction manual.

Purpose of the NESC

112

NESC Committee Structure

Chairman Vice Chair Secretary-IEEE

25 – 35 MembersMainCommittee

ExecutiveSubcommittee

TechnicalSubcommittees

Chairman Secretary

6 - 10 Members

Chairman Secretary

SC 1 – Coordination; Sections 1,2,3SC 2 – GroundingSC 3 – SubstationsSC 4 – Overhead Lines – ClearancesSC 5 – Overhead Lines – Strength & LoadingSC 7 – Underground LinesSC 8 – Work Rules

113

Section 24Grades of Construction

Section 25Loading for Grade B&C

Section 26Strength requirements

• Grades B, C & N (B is the highest)

• Load Factors

• Rule 250B: Combined Ice and Wind District Loading

• Rule 250C: Extreme Wind Loading

• Rule 250D: Extreme Ice with Concurrent Wind Loading

• Strength Factors

Overhead Lines Subcommittee 5

114

Section 24Grades of Construction

Section 25Loading for Grade B&C

Section 26Strength requirements

• Grades B, C & N (B is the highest)

• Load Factors

• Rule 250B: Combined Ice and Wind District Loading

• Rule 250C: Extreme Wind Loading

• Rule 250D: Extreme Ice with Concurrent Wind Loading

• Strength Factors

Overhead Lines Subcommittee 5

Section 27Insulators

• Electrical Strength• Mechanical Strength

115

Section 24: Grades of Construction

• Grade B: (3.85 SF)• Crossing Limited Access Highways• Crossing Railways• Crossing Navigable Waterways

• Grade C: (2.06 SF)• All other standard construction

• Grade N: (Strength shall exceed expected loads)• Mainly used for temporary and emergency construction

116

TRANSVERSEVERTICAL

Section 25 – Loadings for Grade B & C

117

TRANSVERSE

Transverse Loading Usually Governs

VERTICAL

118

Wind Bending Loads On:

118

Calculating Transverse Loads

119

Wind Bending Loads On:WiresIce

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Wind Bending Loads On:WiresIcePole

120


121

Wind Bending Loads On:WiresIcePoleEquipment

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122


Offset Bending Loads

122


123


Offset Bending Loads

Wire Tension123


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Section 25: Loading for Grade B & C

• Rule 250B: District Loading Combined Ice and Wind

• Rule 250C: Extreme Wind Loading (60ft Exemption)

• Rule 250D: Extreme Ice With Concurrent Wind Loading(60ft Exemption)

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NESC District LoadingWinter Storm

126

NESC District Loading

½” Ice – 40 mph½” Ice – 40 mph

¼” Ice – 40 mph¼” Ice – 40 mph

0” Ice – 60 mph0” Ice – 60 mph

Winter Storm

127

NESC District Loading

½” Ice – 40 mph½” Ice – 40 mph

¼” Ice – 40 mph¼” Ice – 40 mph

0” Ice – 60 mph0” Ice – 60 mph40 mph = 4 lbs/sqft

60 mph = 9 lbs/sqft

40 mph = 4 lbs/sqft

60 mph = 9 lbs/sqft

Winter Storm

128

¼” Ice

128

40 mph40 mph

Medium Loading District

129

Wind Load Increase per Wire Sizes

0.75” 1.50” 3.00”

Double wire diameter = Double the load

+100% +200%

2x2x

130

1.25” 2.00” 3.50”+67% +33% +17%

Wind Load Increase With 0.25” Radial Ice

1.50” 3.00”.25” Ice

0.75”

131

0

1

2

3

4

5

6

7

8

9

4ACSR 1/0 336 556

REL

ATIV

E LO

AD

CONDUCTOR (SMALLEST TO LARGEST)

NESC-L

NESC-M

NESC-H

District Loads vs. Wire Size

No ICE

1/4” ICE

1/2” ICE

132



133



Deterministic

134

Extreme Wind– Rule 250C(60 ft. Exclusion)

85 mph = 18.5 lbs/sqft

90 mph = 21 lbs/sqft



85 mph = 18.5 lbs/sqft




Summer Storm

135

Extreme Ice with Concurrent Wind –Rule 250D(60 ft. Exclusion)

Winter Storm

Wind Speeds

30 mph

40 mph

50 mph

60 mph

Wind Speeds

30 mph

40 mph

50 mph

60 mph

Radial Ice

0”

0.25”

0.5”

0.75”

1.0”

Radial Ice

0”

0.25”

0.5”

0.75”

1.0”

136





Deterministic

137





Deterministic

Probabilistic

138





Deterministic

Probabilistic

Probabilistic

139

Section 25 Load Cases

• Rule 250 B - Combined Ice & Wind– Light 0” Ice 60 mph– Medium ¼” Ice 40 mph– Heavy ½” Ice 40 mph– Loads to be Factored

• Rule 250 C – Extreme Wind– Poles Taller than 60 feet Above Ground– Wind only (no ice) – Ultimate Load with probability of occurrence

• Rule 250 D – Extreme Ice with Wind– Poles Taller than 60 feet Above Ground– Ice Thickness with Concurrent Wind– Ultimate Load with probability of occurrence

140

Alternate Method

Strength

Load

Storm Load x 4 (B)

Storm Load x 2 (C)>>

Pole Strength

Pole Strength

141

StrengthPole Strength x SF

Pole Strength x SFAlternate Method

Strength

Load

>>

Storm Load x 4 (B)


Pole Strength

Pole Strength

142



Strength

Load

>>

Storm Load x 4 (B)


Pole Strength

Pole Strength

LoadStorm Load x LF (B)

Storm Load x LF (C)

143

Grade B Grade Cx Grade CRu

le 2

50B

Vertical Loads 1.50 1.90 1.90

Transverse Loads(wind) 2.50 2.20 1.75

Longitudinal Loads 1.10 No Req. No Req.

250C Wind Loads 1.00 1.00 1.00

250D Ice and Wind

loads 1.00 1.00 1.00

Section 25: Table 253.1-Load Factors

144

Grade B Grade Cx Grade CRu

le 2

50B

Vertical Loads 1.50 1.90 1.90

Transverse Loads(wind) 2.50 2.20 1.75

Longitudinal Loads 1.10 No Req. No Req.

250C Wind Loads 1.00 1.00 1.00

250D Ice and Wind

loads 1.00 1.00 1.00

Section 25: Table 253.1-Load Factors

145

Section 26: Strength Factors

Grade B Grade CRu

le 2

50B Metal Structures 1.0 1.0

Wood Structures 0.65 0.85

250C

& 2

50D

Metal Structures 1.00 1.00


Table 261‐1

146


Grade B Grade CRu

le 2



250C

& 2

50D



Fiber Strength (ANSI)× Strength Factor (NESC)=

Allowable Stress of Pole

Table 261‐1

147


Grade B Grade CRu

le 2



250C

& 2

50D



Fiber Strength (ANSI)× Strength Factor (NESC)=

Allowable Stress of Pole

Table 261‐1

148



Strength

Load

>>

Storm Load x 4 (B)


Pole Strength

Pole Strength

LoadStorm Load x LF (B)

Storm Load x LF (C)

149

StrengthPole Strength x .65

Pole Strength x .85Alternate Method

Strength

Load

>>

Storm Load x 4 (B)


Pole Strength

Pole Strength

LoadStorm Load x 2.5 (B)

Storm Load x 1.75 (C)

150

StrengthPole Strength x .65

Pole Strength x .85Alternate Method

Strength

Load

>>

Storm Load x 4 (B)


Pole Strength

Pole Strength

LoadStorm Load x 2.5 (B)

Storm Load x 1.75 (C)

3.85 2.06

151

Section 24: Grades of Construction

• Grade B: (3.85 SF)• Crossing Limited Access Highways• Crossing Railways• Crossing Navigable Waterways

• Grade C: (2.06 SF)• All other standard construction

• Grade N: (Strength shall exceed expected loads)• Mainly used for temporary and emergency construction

Equate the

Total Storm Load

to a

Single Horizontal Load

applied

2 feet from the tip.

900 lb

900 lb Storm Loadx 3.85 (Grade B)

Class 1 4500 lbClass 2 3700 lbClass 3 3000 lbClass 4 2400 lbClass 5 1900 lb

= 3465 lb

NESC ANSI O5.1

Load < Strength

Grade B

155

900 lb Storm Loadx 2.06 (Grade C)

= 1854 lb

NESC ANSI O5.1

Load < Strength

Grade C

Class 1 4500 lbClass 2 3700 lbClass 3 3000 lbClass 4 2400 lbClass 5 1900 lb

157

Length

158

ClearanceLength

159

ClearanceLength

Class

160

Clearance

Capacity

Length

Class

161

Clearance

Capacity

Length

Class


162

Online Courses – MOOC’s

MOOC #1 NESC Overview

MOOC #2 2017 Changes

163

Technical Subcommittees

SC1 - Coordination between technical subcommittees Sections 1, 2 and 3

SC2 - Grounding Methods - Section 9

SC3 - Electric Supply Stations - Sections 10-19

SC4 - Overhead Lines - Clearances - Section 20-23

SC5 - Overhead Lines - Strength and Loading -Sections 24-27

SC7 - Underground Lines - Sections 30-39

SC8 - Work Rules - Sections 40-43

164

Online Courses – MOOC’s

MOOC #1 NESC Overview

MOOC #2 2017 Changes

MOOC #3 Grounding Methods

MOOC #4 Electric Supply Stations

MOOC #5 Overhead Lines – Clearances and S&L

MOOC #6 Underground Lines

MOOC #7 Work Rules

165

NESC Mobile App

• Mobile device or tablet

• iOS, Android, Windows

• Full printed document

• Enhanced features

– Instant access to formulas, equations and calculations with context

– Quick look-up of terms

– Quick access to sections

Released !!!!

166

Tables & Equations

Home Page Table of Contents

NESC Mobile App

167

Search the NESC Search IEEE

NESC Mobile App

168

• Nelson G. Bingel III• ASC O5 Chairman• NESC Chairman


President(678) [email protected]

national wood pole standards44 circumference3effect mg/l= .000264 x fiber strength x circumference 3...

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