national wood pole standardswoodpoles.org/portals/2/documents/woodpolecode_overview.pdf · 1....

1

.

National Wood Pole

Standards

Nelson G. Bingel III – NESC Chairman

President(678) [email protected]

2

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

3

• 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

4

ANSI

American National Standards Institute

4

5

ANSI


ANSI accredits the procedures of standards developing organizations

National consensus standards

Openness, balance, consensus and due process

5

6

ASC O5 Committee

American Standards Committee O5

USERS

PRODUCERS

GENERAL INTEREST


6

7

ASC O5 NESC

Accredited Standards

Committee O5:

Standards for Wood

Utility Structures

• Secretariat: AWPA

• Revised: 5 year cycle

• Founded in 1924

National Wood Pole Standards

7

8

ASC O5 Standards http://asco5.org/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

Poles Glu-Lam Crossarms

8

9

http://asco5.org/

9

10

http://asco5.org/standards/

10

11

Scope

Single Pole

Simple Cantilever

Transverse

Groundline

12

Maximum Stress Point

Max Stress @ 1.5 Diameter Load Point

Solid, Round, Tapered, Cantilever

Distribution Usually Groundline

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

12

13

ANSI O5.1 – Wood Poles

Wood

Quality

Class

Loads

Pole

Dimensions

Fiber

Strength

13

14

Wood Quality

• Allowable knots

14

15

Wood Quality

• Sweep

15

16

Wood Quality

• Growth Rings

16

17

Pole Marking & Code Letters

17

18

Pole Marking & Code Letters

18

19

Transverse Wind Loads

Ice

19

20

Class Loads

2 ft Lc

Horizontal

Class Load (lb)

10 370

9 740

7 1,200

6 1,500

5 1,900

4 2,400

3 3,000

2 3,700

1 4,500

H1 5,400

H2 6,400

H3 7,500

H4 8,700

H5 10,000

H6 11,400

20

21

Class Loads

2 ft Lc

Telco

Distribution

Transmission

Horizontal

Class Load (lb)

10 370

9 740

7 1,200

6 1,500

5 1,900

4 2,400

3 3,000

2 3,700

1 4,500

H1 5,400

H2 6,400

H3 7,500

H4 8,700

H5 10,000

H6 11,400

21

22

Strengths are Average Values

22

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjbr_aUraPLAhVDKx4KHWllBNwQjRwIBw&url=http://www.onlineinvestingai.com/blog/trading-and-the-bell-curve/&psig=AFQjCNEuihH-gdqBIwSi1YUmRIcY8H1bBw&ust=1457054137650024

23

Pole Populations

Wood Poles

Steel Poles

23

P

24

Lc

D

2 ft

Class 1 4,500 lb

Class 2 3,700 lb

Class 3 3,000 lb

Class 4 2,400 lb

Class 5 1,900 lb

Applied Bending Load

Applied Bending Load =

Lc x D (ft-lb)

24

25

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

25

26

Lc

Fiber Strength

Compression

(psi)

Tension

(psi)Fiber Strength

Bending Capacity =

k x fiber strength x C3 (ft-lb)

26

27

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%

27

28

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%

80-90%

Pole’s Bending Strength

In The Outer 2-3” Of Shell!

28

29

Table 1 – Designated Fiber Strength

Group AAir Seasoning

Group BBoulton Drying

Group CSteam Conditioning

Group DKiln Drying

29

30


Southern Yellow Pine 8,000 psi

Douglas fir 8,000 psi

Western red cedar 6,000 psi

30

31

Pole Species

31

Distribution:Southern Yellow Pine

Transmission:Douglas fir

Western red cedar

Southern Pine

Distribution:Douglas fir

TransmissionDouglas fir

Western red cedar

32


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.

4) The designated fiber strength represents a mean, groundline, fiber strength value

with a coefficient of variation equal to 0.20.

32

33

Through-boring

34

Oregon State University

-Through-Boring Project-

34

37

Through-boring

37

38


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.

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.

38

39

2017 Table 1 to add MOE

40


41


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.

42

Circumference Dimensions

TIP

6ft

G/L

Bending Capacity =


42

43

Circumference Dimension Tables

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.

43

44

Annex B: Groundline Stresses

44

45


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

Bending Capacity =


Applied Bending Load =

Lc x D (ft-lb)

45

46

Pole Dimension Table

(in)

Southern Pine and Douglas Fir

47


(in)

Southern Pine and Douglas FirApplied Bending Load=

Class Load x Distance

2,400 lbs x 32 ft =

76,800 ft-lbs

48


(in)

Southern Pine and Douglas FirApplied Bending Load=

Class Load x Distance

Bending Capacity =

k x fiber strength x C3

.000264 x 8000 x 33.53 =

79,401 ft-lbs

2,400 lbs x 32 ft =

76,800 ft-lbs

49

40 ft Class 4 Poles

Douglas fir

(8000 psi)

36 1/2”

Western Red Cedar

(6000 psi)

33 1/2”

2400 lb

49

50


Average circumference tapers

in the groundline zone of a pole

Note 7

50

51

ANSI O5.1 Summary

2 ft Lc

Bending

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

All Species

Same Length & Class

Similar Load Capacity

51

52

Fiber Strength Values

1965 Publication

Forest Products Lab

Fiber Strength

Derivation

52

53

FPL 39 Table 4Final Adopted Fiber Strengths

53

54

FPL 39 Table 4

Final Adopted Fiber Strengths

Near 5% Lower Exclusion Limit

Of Actual Average Bending Strength

Of Three Pole Groups

For Grade B Construction

54

55

Annex C Data < 50 ft

55

56

Annex C Data – 50 ft +

56

57

Full Scale Break Tests

02000400060008000

10000120001400016000

15 25 35 45 55 65 75 85

MO

RG

L (

psi

)

Groundline Circumference (GC) (in)

Douglas Fir Poles

Mean = 8380 psiL5 = 6401 psi Mean = 6630 psi

L5 = 4825 psi

ASTM

EPRI

57

58

Full Scale Break Tests

02000400060008000

10000120001400016000

15 25 35 45 55 65 75 85

MO

RG

L (

psi

)

Groundline Circumference (GC) (in)

Douglas Fir Poles

Mean = 8380 psiL5 = 6401 psi Mean = 6630 psi

L5 = 4825 psi

ASTM

EPRI

No Changeto

Previous Fiber Strengths

58

59

Annex A

Fiber Stress Height Effect

59

60

Annex A

Fiber Stress Height Effect

Round timbers are known to

decrease in ultimate unit strength

with height above ground.

60

61

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

SC

OK

OR

CT

IA

MS

KS

AR

UT

NV

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)

61

62

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

• Southern Yellow Pine 6,634 poles

11 Producers; 16 Locations

• Western Red Cedar 6,982 poles


• Northern Red Pine 2,266 poles


Grand Total 22,859 poles

Pole Circumference Data

62

63

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

63

64

ASC O5 Standards http://asco5.org/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

Poles Glu-Lam Crossarms

64

65

ASC O5 NESC

Accredited Standards

Committee O5:

Standards for Wood

Utility Structures

• Secretariat: AWPA


• Founded in 1924

National Wood Pole Standards

65

66

National Overhead Line Standard

ANSI C2:

National Electrical

Safety Code

• Secretariat: IEEE (Institute of Electrical and

Electronics Engineers)


• Established in 1915

NESC

67

NESC Committee Structure

67

Chairman Vice Chair Secretary-IEEE

25 – 35 Members

Main

Committee

Executive

Subcommittee

Technical

Subcommittees

Chairman Secretary

6 - 10 Members

Chairman Secretary

SC 1 – Coordination; Sections 1,2,3

SC 2 – Grounding

SC 3 – Substations

SC 4 – Overhead Lines – Clearances

SC 5 – Overhead Lines – Strength & Loading

SC 7 – Underground Lines

SC 8 – Work Rules

68

Purpose of the NESC

69

B. NESC rules contain the basic provisions, under

specified conditions, that are considered necessary for

the safeguarding of:

1. The Public

2. Utility workers (employees and contractors), and

3. Utility facilities

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

an instruction manual.

Purpose of the NESC

70

NESC Committee Structure

70

Chairman Vice Chair Secretary-IEEE

25 – 35 Members

Main

Committee

Executive

Subcommittee

Technical

Subcommittees

Chairman Secretary

6 - 10 Members

Chairman Secretary

SC 1 – Coordination; Sections 1,2,3

SC 2 – Grounding

SC 3 – Substations

SC 4 – Overhead Lines – Clearances

SC 5 – Overhead Lines – Strength & Loading

SC 7 – Underground Lines

SC 8 – Work Rules

71

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

72

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

73

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

73

74

TRANSVERSE

V

E

R

T

I

C

A

L

74

Section 25 – Loadings for Grade B & C

75

Wire with Ice

Transverse Loading Usually Governs

76

Wind Bending Loads On:

Wires

Ice

Pole

Equipment

Offset Bending Loads

Wire Tension

76

Calculating Transverse Loads

77

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)

77

78

NESC District Loading

½” Ice – 40 mph

¼” Ice – 40 mph

0” Ice – 60 mph40 mph = 4 lbs/sqft

60 mph = 9 lbs/sqft

78

Winter Storm

79

¼” Ice

40 mph

Medium Loading District

80

Wind Load Increase per Wire Sizes

0.75” 1.50” 3.00”

80

Double wire diameter = Double the load

+100% +200%

2x2x

81

1.25” 2.00” 3.50”

+67% +33% +17%

Wind Load Increase With 0.25” Radial Ice

1.50” 3.00”

.25” Ice

81

0.75”

82

District Loads vs Wire Size

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

82

No ICE

1/4” ICE

1/2” ICE

83



83

Deterministic

84

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

85 mph = 18.5 lbs/sqft

90 mph = 21 lbs/sqft



84

Summer Storm

85

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

Winter Storm

Wind Speeds

30 mph

40 mph

50 mph

60 mph

Radial

Ice

0”

0.25”

0.5”

0.75”

1.0”

85

86



• Rule 250C: Extreme Wind Loading

(60ft Exemption)

• Rule 250D: Extreme Ice

With Concurrent Wind Loading

(60ft Exemption)

86

Deterministic

Probabilistic

Probabilistic

87

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

88

StrengthPole Strength x SF

Pole Strength x SFAlternate Method

Strength

Load

>>

Storm Load x 4 (B)

Storm Load x 2 (C)>>

Pole Strength

Pole Strength

LoadStorm Load x LF (B)

Storm Load x LF (C)

89

Grade B Grade Cx Grade CR

ule

25

0B

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.

25

0C

Wind Loads 1.00 1.00 1.00

25

0D Ice and Wind

loads1.00 1.00 1.00

Section 25: Table 253.1-Load Factors

90

Section 26: Strength Factors

Grade B Grade CR

ule

25

0B Metal Structures 1.0 1.0

Wood Structures 0.65 0.85

25

0C

& 2

50

D

Metal Structures 1.00 1.00

Wood Structures 0.75 0.75

Fiber Strength (ANSI)

× Strength Factor (NESC)=

Allowable Stress of Pole

Table 261-1

90

91

StrengthPole Strength x SF

Pole Strength x SFAlternate Method

Strength

Load

>>

Storm Load x 4 (B)


Pole Strength

Pole Strength

LoadStorm Load x LF (B)

Storm Load x LF (C)

92

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

93

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

93

95

Equate the

Total Storm Load

to a

Single Horizontal Load

applied

2 feet from the tip.

900 lb

96

900 lb Storm Load

x 3.85 (Grade B)

Class 1 4500 lb

Class 2 3700 lb

Class 3 3000 lb

Class 4 2400 lb

Class 5 1900 lb= 3465 lb

NESC ANSI O5.1

Load < Strength

Grade B

97

900 lb Storm Load

x 2.06 (Grade C)

= 1854 lb

NESC ANSI O5.1

Load < Strength

Grade C

Class 1 4500 lb

Class 2 3700 lb

Class 3 3000 lb

Class 4 2400 lb

Class 5 1900 lb

98

IEEE Online Courses – MOOC’s

98

MOOC #1 NESC Overview

MOOC #2 2017 Changes

http://standards.ieee.org/about/nesc/

99

Technical Subcommittees

99

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

100

Online Courses – MOOC’s

100

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

101

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 !!!!

http://standards.ieee.org/about/nesc/mobile_app.html

102

Tables & Equations

Home Page Table of Contents

NESC Mobile App

103

Search the NESC Search IEEE

NESC Mobile App

104

.

National Wood Pole

Standards

Nelson G. Bingel III – NESC Chairman

President(678) [email protected]

national wood pole standardswoodpoles.org/portals/2/documents/woodpolecode_overview.pdf · 1....

Documents