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TABLE OF CONTENTS

INSTRUCTIONS WHEN USING RUS GUIDE SPECIFICATIONS ..............5a

TECHNICAL SPECIFICATIONS ................................... .. 1

1. Scope .................................................. .. 1

2. Definitions ............................................... 1

3. Codes and Standards ....................................... 4

4. General Requirements ...................................... 6

5. Inspection and Testing ....................................17

6. Shipping and Delivery .....................................20

7. Drawings and Information to be Supplied

 by the Manufacturer... ..............................21

8. Approvals, Acceptance, and Ownership ......................22

9. List of Attachments .......................................23

 Attachment A - Pole Framing Drawings .....................25

 Attachment B - Application Requirements ..................27

 Attachment C - Bid Summary-Design Information, Weights,

 And Costs(Information to be Submitted with Proposal) 29

APPENDIX A - COMMENTARY .................................... A-1

APPENDIX B – EXAMPLE POLE FRAMING DRAWING ................... B-1

APPENDIX C - DESIGN EXAMPLE ................................. C-1

APPENDIX D - SELECTED SI-METRIC EQUIVALENTS ................ D-1

APPENDIX E - CONTRIBUTORS .................................. E-1

INDEX: POLES: Concrete

 SPECIFICATIONS AND STANDARDS: Guide Specification for

Standard Class Spun Prestressed Concrete Poles

 Transmission Facilities: Poles (Concrete)

ABBREVIATIONS

ACI American Concrete Institute

AISC American Institute of Steel Construction

ASCE American Society of Civil Engineers

ASTM American Society for Testing and Materials

AWS American Welding Society

FOB Free on Board

IFI Industrial Fasteners Institute

kip 1,000 pounds

ksi kips (1000 lb.) per square inch

mph miles per hour

NESC National Electrical Safety Code

OLF Overload Factor

OHGW Overhead Ground Wire

PCI Prestressed Concrete Institute

psi pounds per square inch

PVC Polyvinyl chloride

RUS Rural Utilities Service
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INSTRUCTIONS WHEN USING RUS GUIDE SPECIFICATIONS

FOR STANDARD CLASS SPUN, PRESTRESSED CONCRETE POLES

A. Purpose: This guide specification provides a basis for

procuring direct embedded standard class spun prestressed

concrete poles. If poles are competitively bid, use of this

specification will eliminate ambiguities which might arise in the

evaluation process.

Terminology used in this specification has been simplified in

order to provide consistency. Referring to the owner can also

mean the owner's representative or engineer.

The owner is responsible for completing this specification and

adding other information, drawings and supplemental requirements

as appropriate. It may be necessary for the owner to modify this

specification in order to consider special applications or

preferences.

B. Scope: This purchase specification covers the technical

aspects of design, materials, manufacturing, inspection, testing,

and delivery of direct embedded standard class spun prestressed

concrete poles. It is recommended that this specification be

limited to poles which are not guyed, not subjected to unbalanced

lateral loads, or do not have deflection limitations or other

special limitations. For concrete pole applications which

consider these items, it is recommended that the owner use Guide

Specification for Spun, Prestressed Concrete Pole and Concrete

Pole Structures, RUS Bulletin 1724E-206. This specification does

not include front-end documents or specifications for

construction. The owner needs to add front-end documents

including instructions to the bidders and general conditions.

This specification may be expanded to include H-frame structures.

C. Initial Design Considerations: There are several engineering

decisions required of the user of this specification to determine

which standard class concrete poles to specify. Some examples

include, but are not limited to:

• Amount of foundation rotation and deflection to consider for

incorporating P-delta moments;

• Location of point of fixity;

• Embedment depths;

• Load cases to be considered in addition to those required by

the National Electrical Safety Code (NESC); and

• Deflection limitations.
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Prior to the selection of a standard class pole, the user should

perform the engineering required for these types of issues or

employ an engineering consultant to do so. See Appendix A for a

discussion of some of these items.

D. Information to be Completed by the Owner - When using these

specifications the owner should detach sheets 1a to 8a and the

Commentary, and add or complete the following:

D.1 Documents and general information to be added to the

technical specification: The following front-end documents and

general information need to be added to this technical

specification:

♦ RUS Form 198 (Recommended for competitive bidding)

♦ Supplemental Instructions to Bidders

♦ General Conditions

It is recommended that RUS Form 198 be used for competitive

bidding. This form covers Notice and Instructions to Bidders,

Proposal, and Equipment Contract. Other supplemental information

which the owner may want to add includes Bid Submission, Bid

Price and Schedule, Bid Acceptance Period, Bid Requirements, Bid

Data, and Bidder's Qualifications. A section on General

Conditions could include such items as Definition of Terms,

Inspection and Acceptance, Interpretation of Bid Documents,

Addenda to the Bid Documents, Insurance, Method of Payment (if

Form 198 is not used), Quantities, and Tabulation of Unit Prices.

D.2 Specifications and technical information to be completed by

the Owner:

a. Configuration requirements and other information (Attachment

A of the specification or equivalent):

(1) Structure dimensions;

(2) Conductor support (type, holes, orientation and height);

(3) OHGW support (type, holes, orientation and height);

(4) Underbuild support (type, holes, orientation and height);

(5) Embedment depths; and

(6) Other hole locations and/or requirements.

b. Strength requirements - Standard class designations for spun

concrete poles, which include ultimate loading and ultimate

strength requirements.

This specification establishes standard concrete pole sizes. The

appropriate standard class pole from Section 4 needs to be
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selected by the engineer.

In the calculations to select the standard class pole, the

engineer should use minimum design loads which meet NESC

requirements appropriate for the loading district, any local

codes, the NESC extreme wind load provisions, and any necessary

extreme ice and wind conditions with the appropriate overload

factors. The design loads account for all loading cases including

wind on pole and secondary stresses from foundation deflection

and rotation, and from vertical loads acting on lateral pole

deflection (P-delta effect).

ASCE Guidelines for Transmission Line Structural Loading can be

used for developing loads produced by climate, accidents,

construction and maintenance. Calculations need to include the

vertical, transverse, and longitudinal loads with wind on the

structure and the dead weight of the structure for any given

loading condition applied simultaneously.

c. Application Requirements (Attachment B to be completed by the

Owner).

(1) Location of climbing and/or working devices and the quantity

of each to be supplied with the poles.

(2) Delivery schedule, F.O.B. location, and name, address, and

telephone number of the owner's contact.

(3) Additional requirements. Additional items such as special

pole color (stain, paint, or dye additive), location of bolt

holes for other attachment requirements, grounding requirements,

cant holes, switch operating mechanisms, etc.

(4) Pole tests required.

E. Information to be Completed by the Manufacturer

E.1 The owner should have the following information completed

and submitted by each bidder (Attachment C or equivalent).

a. Calculated weight of each concrete pole;

b. For each standard class pole ultimate loading, provide

section and strength properties, including the ultimate,

cracking and zero tension moments and deflections, at

maximum five foot intervals along the pole;
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c. Pole diameter at top, bottom, and groundline;

d. Tip and butt wall thickness;

e. Prestress strand - quantity, size and dropout location;

f. 28-day compressive strength of concrete; and

g. Diameter taper (in/ft).

E.2 The owner should have the following information completed by

the successful bidder prior to pole manufacture:

a. Type of material of major components (ASTM number and

grade);

b. Quantity, size and grade of prestressing strands or

other reinforcement;

c. Description of pole including thickness, length,

diameter, and taper; and

d. Design exceptions.

E.3 Test reports as requested by the owner.
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TECHNICAL SPECIFICATION FOR STANDARD CLASS

SPUN, PRESTRESSED CONCRETE POLES

1. SCOPE This specification covers the design, materials,

manufacture, inspection, testing, drawings, shipping, and

delivery of direct embedded standard class spun prestressed

concrete poles.

2. DEFINITIONS

Admixture - Any material other than water, aggregate, or cement

that is used as an ingredient of concrete and added to concrete

before or during its mixing to modify its properties.

Appurtenance - Any hardware or structural members that are

attached to the concrete pole to make a complete structure.

Bonding, Electrical - The electrical interconnecting of

conductive parts, designed to maintain a common electrical

potential.

Cant Hole - A through hole in the pole which is used in rotating

the pole about its axis during setting. The hole is typically 

1-1/2” in diameter and located approximately 4 feet above the

groundline.

Circumferential Cracks - Cracks that parallel a cross-section of

a concrete pole.

Cracking Moment - The moment which is developed in the pole at

the time the cracking strength of the pole is experienced.

Cracking Strength - The point at which the concrete just begins

to separate due to exceeding the tensile strength of the concrete

on the tension face of the pole.

Deleterious Substance - Any substance that is not desirable in a

mixture, usually causing harm in sufficient quantities.

Dropout, Steel Cable - The terminating point of any longitudinal

steel that is not continuous for the length of the pole.

Efflorescence - The formation of a white film on the surface of

the pole, typically caused by the emergence of chlorides during

curing.

Embedment - That portion of the pole which is designed to be

located in the ground or other supporting medium.
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Groundline - The point at which the embedment begins. Resistance

from the supporting soils or other medium begins at or below

groundline. Groundline is defined for transmission line design to

determining ground clearances and for locating climbing devices,

cant holes, nameplates, etc.

Group of Bolt Holes - All of the holes in which a single hardware

assembly will be attached.

Guyed Structure - A structure in which cable supports are used to

increase its lateral load resistance.

In-Line Face - The face of the pole which “faces” an adjacent

structure in the line.

Longitudinal Cracks - Cracks in concrete that are parallel to the

long axis of the pole.

Longitudinal Reinforcement - The reinforcing steel which is

installed along the long axis of the pole.

Manufacturer - The company responsible for the fabrication of the

poles. The manufacturer makes the poles based on the design

drawings developed by the structural designer, which is the

engineer responsible for the structural design of the poles and

is usually employed by the manufacturer.

Overload Factor - A multiplier which is applied to each of the

vertical, transverse and longitudinal structure loadings to

obtain an ultimate load. The multiplier takes into account the

variability of climatic events as well as the importance of the

structure.

Owner - The Rural Utilities Service borrower procuring the

concrete poles.

P-Delta Moment - The additional moment created by vertical loads

acting on the structure which deflects from its unloaded

position.

Point of Fixity - The point on the pole at or below groundline

where the maximum moment occurs. Location of this point is

dependent on the characteristics of soils around the embedded

portion of the pole

Pole End Squareness - A measure of how perpendicular the finished

surface of the pole butt is to the longitudinal axis of the pole.
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Pole Failure - The point at which the maximum strength of the

pole is realized. Failure usually occurs with crushing of the

concrete or permanent deformation.

Pole Sweep - The measure of deviation from straightness along the

length of the pole.

Post-Tensioned Steel Strand - The longitudinal reinforcement that

has been tensioned after the concrete has hardened.

Prestressed Concrete - Reinforced concrete in which internal

stresses have been introduced to reduce potential tensile stress

in concrete resulting from loads.

Pretensioned Steel Strand - The longitudinal reinforcement that

has been tensioned before concrete is placed. Also referred to

as prestressed steel strand.

Pyrite Staining - A pale brass-yellow colored stain in the

concrete caused from the concrete mixture containing an excess

amount of iron disulfides.

Reinforcing Steel - Any steel for the purpose of reinforcement of

the concrete, including longitudinal reinforcement, spiral

reinforcement and deformed reinforcing bars.

Release Strength - The minimum concrete strength that is

necessary before the pretensioned strands can be released.

Spiral Reinforcement - Steel reinforcement, continuously wound in

the form of a cylindrical helix, that encloses the longitudinal

steel.

Spun Concrete Pole - A pole which is manufactured by placing

prestressed steel strands and spiral reinforcement in a mold,

adding fresh concrete and spinning the mold to form the pole.

Standard Class Pole - A direct embedded spun concrete pole which

is designed according to a standardized strength and loading

criteria established by the Owner.

Tip Load - The horizontal load which is applied to the standard

class pole at a distance of 2 feet from the pole tip.

Ultimate Load - The maximum design load which includes the

appropriate overload factor.

Ultimate Moment Capacity - The moment which is developed in the

pole at the time the ultimate strength of the structure is
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realized.

Ultimate Strength - The maximum strength in the stress-strain

diagram. For the pole, this is considered to be the point at

which the pole fails, usually with crushing of the concrete.

Yield Strength - The minimum stress at which a material will

start to physically deform without further increase in load or

which produces a permanent strain. This is known as the elastic

limit of the material.

Zero Tension Strength - The moment at which a crack that was

previously created by exceeding the cracking moment strength will

open again. Under this condition, an applied moment will not

cause any tensile stress in the concrete. It will always be less

than the cracking moment strength.

3. CODES AND STANDARDS

Codes, standards, or other documents referred to in this

specification are to be considered as part of this specification.

In the event of a conflict between this specification and the

National Electrical Safety Code (NESC), the NESC shall be

followed. In the event of a conflict between this specification

and all other referenced documents, this specification shall be

followed. If a conflict between several referenced documents

occurs, the more stringent requirement shall be followed. If

clarification is necessary, contact the owner.

The most recent editions of the following codes and standards

shall be followed in the design, manufacture, inspection,

testing, and shipment of spun, prestressed concrete poles.

3.1 American Concrete Institute (ACI): 

ACI 318, Building Code Requirements for Reinforced Concrete

3.2 Prestressed Concrete Institute (PCI):

MNL 116, Manual for Quality Control for Plants and

Production of Precast Prestressed Concrete Products

3.3 American Welding Society (AWS):

AWS D1.1, Recommended Procedures for Welding, Reinforcing

Steel, Metal Inserts, and Connections in Reinforced Concrete

Construction
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3.4 American Society for Testing and Materials (ASTM):

ASTM A82 Steel Wire Plain, For Concrete Reinforcement

ASTM A416 Steel Strand, Uncoated 7-wire For Prestressed

Concrete

ASTM A421 Uncoated Stressed Relieved Steel For Prestressed

Concrete

ASTM A496 Steel Wire, Deformed For Concrete Reinforcement

ASTM A615/A615M Deformed and Plain Billet-Steel Bars For Concrete

Reinforcement

ASTM A617/A617M Axle-Steel Deformed and Plain Bars For Concrete

Reinforcement

ASTM A641M Zinc Coated (Galvanized) Carbon Steel Wire-Metric

ASTM A706A/A706M Low Alloy Steel Deformed Bars For Concrete

Reinforcement

ASTM C31 and 39 Specifications for Sampling Concrete and Testing

Concrete Cylinders

ASTM C33 Concrete Aggregates

ASTM C131 Standard Test Method for Resistance to Degradation

of Small-Size Coarse Aggregate by Abrasion and

Impact in the Los Angeles Machine

ASTM C150 Portland Cement

ASTM C172 Sampling Freshly Mixed Concrete

ASTM C289 Testing Potential Alkali-Silica Reactivity of

Aggregates

ASTM C494 Chemical Admixtures For Concrete

ASTM C881 Epoxy-Resin-Base Bonding Systems for Concrete

ASTM C1089 Standard Specification For Spun Cast Prestressed

Concrete Poles

3.5 Industrial Fasteners Institute (IFI):

Fastener Standards

3.6 American National Standards Institute (ANSI) C2, National

Electrical Safety Code
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3.7 American Society of Civil Engineers/Prestressed Concrete

Institute (ASCE/PCI) Joint Committee on Concrete Poles:

Guide for the Design of Prestressed Concrete Poles, latest

edition

4. GENERAL REQUIREMENTS The design, fabrication, processes,

tolerances, and inspection of poles shall conform to the

following:

4.1 Design Requirements:

4.1.1 Pole designs shall be prepared from the attached

configuration drawings, design loads and strength requirements

for the standard class poles. Poles shall be designed by the

ultimate strength method as explained in ACI 318. The point-offixity shall be considered to be located at a distance from the

pole butt which is equal to 7% of the pole length. The pole shall

be symmetrically designed such that the strength required in any

one direction shall be required in all directions about the

longitudinal axis. The poles shall be uniform taper from tip to

butt.

4.1.2 Using the corresponding values in Table 1, the poles shall

be designed for the following requirements as illustrated by

Figure 1:

a. The reinforcing steel shall begin at the pole tip and the

pole shall develop the minimum ultimate moment capacity

required in Table 1 at a distance of five feet from the pole

tip;

b. The pole shall develop the minimum ultimate moment

capacity along the pole to the point-of-fixity which is

calculated by multiplying the tip load in Table 1 by the

distance from the tip load;

c. The reinforcing steel required at the point-of-fixity

shall continue to the pole butt.

4.1.3 The poles shall be designed to withstand the specified tip

loading without exceeding a pole deflection of 15 percent of the

pole height above the point of fixity when tested under short

term loading conditions in accordance with the horizontal test

procedures described in the Guide for the Design of Prestressed

Concrete Poles (ACSE/PCI Joint Committee on Concrete Poles).
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FIGURE 1

Minimum Ultimate Moment Capacity Diagram along the Pole

4.1.4 The poles shall be designed to withstand 40 percent of the

specified tip loading without exceeding a pole deflection of

5 percent of the pole height above the point of fixity when

tested under long term loading conditions in accordance with the

horizontal test procedures described in the Guide for the Design

of Prestressed Concrete Poles (ACSE/PCI Joint Committee on

Concrete Poles).

4.1.5 Poles shall be designed so that the cracking strength of

the pole exceeds 40 percent of the required ultimate strength.

4.1.6 Poles shall be designed so that the zero tension strength

of the pole exceeds 28 percent of the required ultimate strength.

Load

Tip

(Tip Load X D)

Point-of-Fixity

Groundline

Pole Butt

5'

D

2'

Strength Governed

By Section 4.1.2.(c)

Strength Governed

By Section 4.1.2.(a)

By Section 4.1.2.(b)

Strength Governed

Pole Tip (top)

Owner Defined
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TABLE 1

Strength Requirements

Standard Class

Designations For Spun

Concrete Poles

Minimum

Ultimate Moment Capacity

At Five Feet From Pole

Tip(Ft.-Kip)

Tip Load

(Lbs.)

C-12.0 96 12,000

C-11.0 88 11,000

C-10.0 80 10,000

C-09.0 72 9,000

C-08.0 64 8,000

C-07.1 57 7,125

C-06.2 50 6,250

C-05.4 44 5,450

C-04.7 38 4,700

C-04.0 32 4,000

C-03.4 27 3,375

C-02.8 23 2,825

C-02.3 19 2,325

C-01.9 15 1,875

4.1.7 Poles shall be designed to withstand a one-point (tilting)

pickup during erection. The poles shall be designed for two-point

pickup for horizontal handling. Poles shall be designed for the

loads generated from handling and erecting without exceeding the

cracking moment capacity of the poles.

4.1.8 The pole design shall include allowances for loads from

handling, transportation and erection without failure, permanent

deformation, or damage to the pole when handled according to the

manufacturer’s instructions. (See Section 6.1)

4.1.9 The design of each pole shall be performed using the

applicable codes and standards listed in Section 3 of this

specification.
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4.1.10 Pole design and design calculations shall be the

responsibility of the manufacturer.

4.2 Materials:

4.2.1 The chemical properties of materials used in the

manufacture of the poles shall meet the requirements of the

applicable ASTM specification and be such that noticeable pyrite

staining or efflorescence due to sulfates and/or chlorides does

not occur.

4.2.2 All anchors and inserts provided by the manufacturer shall

be hot dip galvanized or noncorrosive material. Cadmium-plated

and aluminum material shall not be used. All inserts shall be

noncorrosive materials designed and manufactured for the intended

purpose and used according to manufacturer's recommendations. If

the manufacturer considers lifting devices necessary or

desirable, suitable flush inserts may be cast into the pole with

removable lifting attachments.

4.2.3 The concrete shall have a minimum 28-day compressive

strength of 5,000 psi with a maximum water-cement ratio of 0.40.

Higher strengths and lower water-cement ratios are encouraged and

may be necessary to offset steel cover requirements.

4.2.4 The cement shall be either Type I, II, III, or V Portland

cement conforming to ASTM C150.

4.2.5 Fine aggregate shall be a natural sand, consisting of

clean, strong, hard, durable uncoated particles conforming to

ASTM C33, and all specifications included therein. The aggregate

shall be well graded from No. 4 to No. 200 sieve. Deleterious

substances shall not comprise more than 5 percent of the sample.

4.2.6 Coarse aggregate shall be clean, tough, crushed stone

conforming to ASTM C33, and all specifications included therein.

The aggregate shall be well graded from a 3/4 inch to a No. 8

sieve with no more than 5 percent of the sample passing through a

No. 8 sieve. Deleterious substance content shall not exceed

5 percent of the sample. Resistance to abrasion shall not exceed

40 percent as tested in conformance with ASTM C131. Absorption

shall be less than 4 percent or aggregate shall be saturated with

water prior to use in concrete.

4.2.7 Aggregate shall be tested in accordance with ASTM C289 to

determine an alkali-aggregate reaction. Crushed rock or

partially crushed rock shall be the source of the aggregate.
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4.2.8 Water shall be clean, free from undesirable amounts of

oils, acids, alkalis, salts, organic materials, or other

deleterious substances.

4.2.9 Admixtures shall conform to ASTM C494. Air entraining

admixtures can be used if approved by the owner. Admixtures

shall not contain chloride ions in quantities that would cause

the total chloride content of the concrete to exceed 0.4 pound

per cubic yard.

4.2.10 Prestressing steel mechanical properties, reinforcing

steel and spiral reinforcement shall be in accordance with the

applicable ASTM specifications listed in Section 3 of this

specification.

4.2.11 Concrete mix design requirements listed above can be

altered with the owner's approval.

4.3 Workmanship:

4.3.1 The pole shall be circular in cross section and the

diameter, as measured at any location on the pole, shall not vary

by more than 1/4 inch from any other measurement taken on that

cross section.

4.3.2 The pole shall have a uniform taper from top to butt.

4.3.3 Deviation of the pole from straightness is allowed in one

plane and one direction only. A straight line joining the edge

of the pole at the butt and the edge of the pole at the top shall

not be further from the surface of the pole at any point by more

than the accumulated value of 0.25 inches for each 10 feet of

length between the two ends. The detensioning operation shall be

performed in a manner to keep the prestressing forces

symmetrical.

4.3.4 Prestressing steel stress limits shall not exceed:

1. 80 percent of the ultimate strength or 94 percent of the

yield strength or the maximum value recommended by the

manufacturer of prestressing steels or anchorages for

jacking force;

2. 74 percent of the ultimate strength or 82 percent of the

yield strength immediately after prestress transfer; and

3. 70 percent of the ultimate strength for post-tensioned

steel at anchorages and couplers immediately after

anchorage.
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4.3.5 Spiral reinforcement shall cover the entire pole length. 

The minimum clear spacing of spiral reinforcement in the top 2

feet and bottom 2 feet of the pole shall be 4/3 of the maximum

coarse aggregate or three times the strand diameter, whichever is

larger, but not less than one inch. The maximum clear spacing

for the remainder of the pole shall not exceed 4 inches.

4.3.6 Clear distance between prestressing steel strands shall be

either 4/3 times the maximum aggregate size or 3 times the strand

diameter, whichever is larger. In the event that this condition

is not met at the pole tip, closer spacing would be permitted

provided that the placement of concrete can be accomplished

satisfactorily, adequate stress transfer can take place, and

appropriate provisions are used for maintaining spacing between

the prestressing steel strands.

4.3.7 The manufacturer shall provide holes through each pole as

specified on the pole framing drawing(s), included as

Attachment A. Preformed holes shall be cast using rigid PVC

inserts (or other suitable material) held firmly in place. Plugs

may be used with the owner's approval. Preformed inserts shall

be sized for the specified hole diameter and shall be full length

of pole diameter for all through holes. Unless otherwise noted

on the drawings, holes shall be perpendicular to and pass through

the centerline of the pole.

4.3.8 The pole manufacturer shall provide preformed inserts at

two locations to allow air circulation within the pole. Inserts

shall be 1 inch minimum diameter and shall have a louvered

opening. The inserts shall be located within 10 feet of the tip

and within 10 feet above the groundline.

4.3.9 Holes may not be drilled through the pole wall, except as

specifically necessary to correct errors or omissions and only if

approved by the owner.

4.3.10 The longitudinal steel shall not be cut for any reason

unless approved by the owner. The owner may reject any pole in

which the longitudinal steel is cut. All exposed steel resulting

from drilled holes shall be covered with an epoxy paste per

ASTM C881 Type III. Areas with moderate or severe spalling shall

be cleaned and reformed with an epoxy paste or epoxy concrete per

ASTM C881 Type II.

4.3.11 The owner shall have the right to reject any pole in

which the performance of a bolted connection may be reduced due

to the lack of a cleanly preformed or drilled hole.
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4.4 Manufacturing Tolerances:

Manufacturing tolerances shall be limited to the following:

±2 inches, or ±1 inch ±1/8 inch per 10 feet of

length, whichever is greater (i.e. - 120 foot

pole shall have a length of 120 feet ±21⁄2

inches)

Pole Length

-6 inches or +12 inches for assembled spliced

structure

Pole Diameter ±1/4 inch

Wall Thickness 1/4 inch or 12 percent of wall thickness.

(Note: this requirement may be waived provided

that the structural adequacy and durability

are not impaired.)

Pole End Squareness ±1/2 inch per foot of pole diameter

Pole Sweep 1/4 inch per 10 feet of pole length

Pole Weight ±10 percent of calculated value

Location of

Longitudinal

Reinforcement

+1/4 inch and ±1/8 inch reinforcement

placement for the centroid of a group

Location of Spiral

Reinforcement

±25 percent of clear spacing required with

total reinforcement placement required

quantity per 3 feet of pole length maintained.

Location of Group of

Bolt Holes from Top

of Pole

±2.0 inches

Location of Bolt

Holes Within a Group

of Bolt Holes

±1/8 inch

Location of

Centerline Between

Groups of Bolt Holes

±1.0 inch

Bolt Hole Diameter ±1/16 inch of specified diameter

Bolt Hole Alignment Not to vary from the longitudinal pole

centerline of that group of holes by more than

1/8 inch

Location of

Identification Plate

±2.0 inch

4.5 Grounding:

4.5.1 An external pole ground wire shall be used. Threaded

inserts for attaching ground wire clips that hold the external
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Page 13

ground wire shall be sized and positioned per the attached

drawings.

4.5.2 Except for bonding of the steel tendons, there shall be no

internal pole grounds. A minimum of one longitudinal steel

strand shall be bonded electrically to a threaded bronze insert

at the top and bottom of the pole. Each bond shall be located

within the top 2 feet of the pole top and at 4 feet above

groundline (See Attachment A). For spliced poles an additional

bond shall be provided above and below the splice to a threaded

bronze insert within 24 inches of the splice. Steel splice

sections shall have the appropriate number of grounding

attachments. This bonding system shall be noncorrosive and shall

be approved by the owner.

4.5.3 If required by the owner, manufacturer shall provide

ground wire clamps for all ground wire attachments.

4.6 Climbing Devices:

4.6.1 Clips for removable ladders shall begin not closer than 3

feet above ground for a direct embedded pole and extend to the

top of the pole. Each ladder clip shall be designed to support a

minimum 1,000 lb. shear working load. Ladder clips shall be

located to avoid interference between ladders and other

attachments.

4.6.2 Removable step bolts shall be provided with spacing as

indicated beginning 8 feet above groundline and extending to the

structure top. Each step lug and step bolt shall be capable of

withstanding a minimum of a 500 lb. working load. Step bolt

mounting nuts shall be spaced at 1 foot 6 inch intervals and

oriented to provide maximum ease of climbing.

4.7 Inserts:

4.7.1 Inserts shall be made of materials which will not

deteriorate in the environment in which they are placed. The

insert shall be made of materials that will not react unfavorably

with the concrete or fasteners. The insert shall not be made of

materials that will corrode and stain the concrete.

4.7.2 Inserts shall not fail before the pole reaches ultimate

strength, unless permitted by the owner.

4.8 Cover:

4.8.1 There shall be a minimum of 3/4 inch of clear concrete

cover over all longitudinal reinforcement and all spiral
Bulletin 1724E-216

Page 14

reinforcement as a result of the concrete spinning process. 

Poles not meeting this requirement shall be rejected except as

allowed by Section 4.8.2.

4.8.2 There shall be a minimum specified wall thickness of 2.5

inches of spun concrete at all points along the pole.

4.8.2.1 An actual wall thickness of less than 2.5 inches of spun

concrete may be allowed from the pole tip to 3 feet below the

pole tip provided the cover requirements of Section 4.8.1 are met

in the spinning process and provided the pole can meet all other

requirements of the specifications.

4.8.2.2 The owner shall, as soon as possible, be notified of any

poles with less than 3/4 inch of spun concrete inside cover

within 3 feet of the pole tip. At the owner's sole discretion,

the owner may reject the pole or may allow the pole to be

repaired by swabbing the interior with an epoxy liner (per ASTM

C881 - Type V, Class B or C) and plugging with 3,000 psi.

concrete to the owner's satisfaction to a distance of 42 inches

from the tip. No pole shall be plugged or considered for

acceptance by the owner unless assurance is made by the

manufacturer that the repaired pole can meet all requirements of

this specification.

4.9 Splices:

4.9.1 Flange-bolted or slip-joint type of splices are permitted.

 When required, flange-bolted type splice shall be used at guyed

structures.

4.9.2 The reinforcing steel and connection apparatus comprising

the splice shall be properly anchored as part of the pole. The

pole shall be designed to fail before the splice fails by

yielding of the splice steel.

4.9.3 The axis of the pole shall not be distorted after the pole

is mated. Shims shall not be used to straighten the pole unless

approved by the owner. The owner reserves the right to reject a

pole based on the improper mating of a pole splice.

4.10 Appurtenances:

4.10.1 Appurtenance material shall be supplied by the owner. The

owner shall also provide the manufacturer of the connectors

and/or members with the locations, orientations, sizes, types,

and strength capacities of the appurtenances.

4.10.2 The concrete pole manufacturer is responsible for the
Bulletin 1724E-216

Page 15

proper design coordination and fit up of all appurtenance

connections and members to the pole(s). Manufacturer shall

notify owner if any appurtenance material supplied by owner will

not result in properly designed structure.

4.11 Finishing:

4.11.1 The surface of the pole shall have a smooth finish with

no unsealed cracks. Cracks shall be sealed either by use of an

epoxy injection system following the epoxy manufacturer's

specifications, or by V-notching the crack on a 1:1 slope to a

minimum depth of 1/4 inch, then filling the V-notch with an epoxy

seal per ASTM C881 Type IV. Covering the crack with an epoxy

coating is not allowed.

4.11.2 Small cavities caused by air bubbles, honeycomb spots, or

other small voids, shall be cleaned thoroughly, saturated with

water and then carefully pointed with a cement mortar. A small

cavity is defined as one not larger than 1/2 inch in diameter or

deeper than 1/4 inch.

4.11.3 If any cavities or voids absorb water which indicate the

void extends into wall of the pole, then the pole shall be

rejected.

4.11.4 The manufacturer shall seal both ends of the pole and

protect the steel strands from corrosion using a suitable epoxy.

The system used shall be approved by the owner.

4.11.5 The center void at the top end of the pole shall be

sealed with a minimum 6 inch thick 1000 psi strength concrete

plug and the pole tip capped. The pole tip cap shall be a

suitable epoxy-aggregate mortar securely bonded to the pole, or

shall be a metal or polymer cap securely held in place with set

screws. Sharp edges shall be tooled to form smooth, chamfered

corners. The manufacturer shall assure that the capping method

will prevent weather intrusion into the pole and prevent pole tip

deterioration.

4.11.6 The center void at the bottom end of the pole shall be

sealed with a minimum 12 inch thick 1000 psi strength concrete

plug. The plug shall be securely bonded to the pole and shall be

tooled to form a smooth, uniform bearing surface. A PVC formed

hole shall be provided in the center of the plug to allow for

drainage.

4.11.7 Where application of epoxy-aggregate mortar is specified,

the surface of the pole where the mortar is to be applied shall

first be coated with the epoxy coating. This coating shall be
Bulletin 1724E-216

Page 16

allowed to cure to a tacky, but not hardened state, before the

mortar is applied. After the mortar has been applied and allowed

to cure for 24 hours, a top coat of epoxy coating, 5 mil thick,

shall be applied over the mortar and the surrounding area of the

pole.

4.12 Marking:

4.12.1 Each pole shall be identified with the manufacturer's

identification plate. The following information shall be stamped

into the plate with letters not less than 1/4 inch in height:

• Manufacturer's name

• Day, month, and year of manufacture

• Structure number

• Length and class of pole

• Ultimate moment capacity at groundline

• Pole framing designation (per framing guide) or pole type

• Owner's name

4.12.2 The manufacturer's identification plate shall be

fabricated from a noncorrosive, nonstaining metal such as bronze,

brass, Series 300 stainless steel, or an aluminum alloy that will

not react unfavorably with concrete. The plate shall have

suitable anchor or anchors welded to the back of the plate to

permit bonding to the pole.

4.12.3 The identification information listed above may be cast

into the surface of each pole. These marks shall be at least 3/4

inch in height and 1/8 inch deep.

4.12.4 The identification plate or cast in-place markings shall

be located on an in-line face of the pole in the direction of the

transmission line. The bottom of the identification plate or

last line of the cast in-place markings shall be located five

feet above the defined groundline.

4.12.5 Each pole shall be marked with the information listed

below. A permanent marker shall be used and the writing shall be

small but legible. For spliced poles, each section shall be

marked as below:

a. Support points;

b. Two-point pickup location for handling the pole in the

horizontal position;

c. One-point pickup location for use in raising the pole to
Bulletin 1724E-216

Page 17

a vertical position and handling during the setting

operation;

d. Pole length and class, fabrication number, structure

number, and pole framing guide number on the butt of the

pole; and

e. Cant hole locations, if required by owner.

5. INSPECTION AND TESTING

5.1 General:

5.1.1 Manufacturing and testing procedures shall be in

compliance with applicable codes and standards listed in Section

3 in this specification.

5.1.2 Upon request, the manufacturer shall furnish the owner

with certified test reports for the steel and concrete used.

5.2 Inspection:

5.2.1 The manufacturer shall make adequate tests and inspections

to determine that each of the poles furnished is in strict

accordance with this specification. At the request of the owner,

the manufacturer shall submit a quality assurance report to the

owner prior to the shipment of each pole and shall include the

following minimum information:

• Fabrication number and owner's structure number;

• Minimum and maximum tip wall thicknesses and steel

coverages (to inside and outside) measurements shall be

made at 3 inches from the tip;

• Minimum and maximum butt wall thicknesses and steel

coverages (to inside and outside) measurements shall be

made at 3 inches from butt;

• Condition of pole interior and evidence of exposed rings

or reinforcement steel;

• Proper hole and insert locations and sizes;

• Evidence of cracking during or after two-point handling;

• Actual manufactured pole weight;

• Report of any repairs made to the pole;

• Date of manufacture and inspection(s); and

• Inspector's seal.

5.2.2 All material and workmanship shall be subject to

inspection, examination, and test for conformance to the

requirements of this specification by the owner. The inspection,

examination, or testing could be done at any time during material
Bulletin 1724E-216

Page 18

procurement, manufacturing, storage periods, transit, or at the

pole destination. Inspection, examinations, and tests may be

waived by the owner, but in no case shall this be interpreted as

releasing the manufacturer from the manufacturer's

responsibilities for delivering poles that meet the requirements

of this specification.

5.2.3 The owner shall have free entry, at all times, while work

is being carried on, to all parts of the manufacturer's plant

where manufacture of the owner's poles is being performed. The

manufacturer shall afford the owner reasonable facilities,

without charge, to satisfy the owner that the poles are being

manufactured in strict accordance with this specification.

5.2.4 The manufacturer shall furnish certified test reports to

the owner, upon request, showing the results of all of the tests

required by this specification and applicable reference

specifications.

5.2.5 Tests shall be in accordance with all applicable standard

specifications and codes.

5.2.6 Failure of the manufacturer to comply with these

specifications will be sufficient reason for rejection of any or

all poles which do not comply with these specifications.

5.3 Concrete and Aggregate Testing:

5.3.1 Concrete used on owners' poles shall have the quality to

meet the design strength and other requirements included in this

specification.

5.3.2 For manufacturers that batch their own concrete, the

manufacturer shall take a minimum of 8 concrete test cylinders

per representative sample. Samples shall be taken at minimum

intervals of one per day, one per 25 cubic yards of concrete

batched, and with each change in raw material supplier for

batches used to make the owner's poles. The test cylinders for

each day's concrete that is batched shall be tested for

compressive strength as follows:

a. Minimum of one for determining release strength;

b. Minimum of one at 7 days;

c. Minimum of one at 14 days; and

d. Minimum of one at 28 days.

5.3.3 For manufacturers that acquire concrete from outside

sources, test cylinders shall be taken from each truck load of

concrete and tested in accordance with this specification.
Bulletin 1724E-216

Page 19

5.3.4 Test cylinders shall be prepared, then cured in the same

curing environment as the pole itself or cured per the applicable

ASTM specification.

5.3.5 Upon request from the owner, the manufacturer shall

provide owner statistical data on concrete strength quality in

accordance to applicable ACI and ASTM specifications. A

correlation factor between rodded cylinders and the spun

concrete, substantiated by test data, shall be provided.

5.4 Structure Testing:

5.4.1 Details of all test procedures contained herein and

methods of measuring and recording test loads and deflections

shall be specified by the manufacturer and approved by the owner

prior to manufacture.

5.4.2 Material procurement for test poles shall be identical to

material procurement procedures for regular production run poles.

5.4.3 The design load testing of any specific pole shall be on a

full-scale basis. Costs for such testing shall be the

responsibility of the owner, shall be separated from the

manufacturer's bid, and shall be negotiated in advance of any

test preparation.

5.4.4 The number, location, direction, holding time, sequence,

and increments of the test loads along with the number, location,

and direction of deflection readings for an individual pole test

shall be approved by the owner prior to pole testing.

5.4.5 The method of attaching the test loads to the pole,

applying the test loads, measuring and recording the test loads,

and measuring and recording the deflections shall be approved by

the owner prior to pole testing.

5.4.6 A full report listing results shall be submitted to the

owner after completion of all testing. Copies of mill test

reports shall be included in the load test report. The report

shall also include a complete description of the load tests with

diagrams and photographs. If required, the manufacturer shall

provide the owner with the following testing data:

a. Location of testing;

b. Method of full scale testing: upright or horizontal; and

c. The pole tester shall issue the owner three (3) copies

of the Pole Test Report. This report shall include

descriptions, tools, and drawings describing the above

test.
Bulletin 1724E-216

Page 20

5.4.7 Use of any factory tested poles to meet order requirements

shall be determined by the owner.

6. SHIPPING AND DELIVERY

6.1 Shipping:

6.1.1 Each shipment shall be accompanied by a list of all parts,

identifiable by structure type and number. Bolts and

miscellaneous hardware shall be identified by the list for match

up with the respective pole shaft. All parts required for any

one structure shall be in one shipment, unless otherwise agreed

to by the owner.

6.1.2 The owner and owner's representative shall be notified

prior to shipment that such shipment is to take place, and the

owner reserves the right to postpone a shipment. The owner has

the right to inspect the components prior to shipment. The

notification of a shipment shall give quantities, weight, name of

common carrier used, and expected time of arrival.

6.1.3 Poles shall be lifted and supported during manufacturing,

stockpiling, and transporting only at the lifting or support

points, or both, as designed by the manufacturer.

6.1.4 Transportation and site handling shall be performed with

acceptable equipment and methods by qualified personnel. The

manufacturer shall exercise precaution to protect poles against

damage in transit.

6.1.5 Poles shall be sufficiently cured before shipment to

resist forces from handling, transportation, and construction.

6.1.6 Handling instructions shall be included with the pole

shipment.

6.2 Delivery:

The owner (or the owner's construction contractor) may take

delivery at a designated location or with the delivering

carrier's cooperation and consent, have the poles transported to

the installation locations with the carrier's equipment. The

manufacturer shall coordinate and cooperate with the owner to

ensure smooth and efficient delivery of poles. The owner will

provide all labor, equipment, and materials for the unloading of
Bulletin 1724E-216

Page 21

poles at the project site. A pole is considered delivered when

the pole is lifted from the trailer or semitrailer of the

delivery carrier by the owner.

7. DRAWINGS AND INFORMATION TO BE SUPPLIED BY THE MANUFACTURER

7.1 Information to be Supplied with the Proposal:

a. Calculated weight of each concrete pole.

b. For each standard class pole, provide section and

strength properties, and the ultimate, cracking and zero

tension strengths at maximum five foot intervals along

the pole to demonstrate conformance with the

requirements of Sections 4.1.2, 4.1.5, and 4.1.6.

c. For each standard class pole, provide pole deflection

calculations at maximum five foot intervals along the

pole using the specified tip loading in order to

demonstrate conformance with the requirements of

Sections 4.1.3 and 4.1.4.

d. Pole diameter at top, bottom, and groundline.

e. Tip and butt wall thickness.

f. Prestress strand - quantity, size and dropout location.

g. Design strength of concrete (28 day compressive

strength).

h. Diameter taper in/ft.

7.2 Information and Drawings to be Supplied for Owner’s Approval

Prior to Fabrication:

7.2.1 After the manufacturer's proposal has been accepted, the

manufacturer shall submit to the owner two prints of each

fabrication drawing. One set of these drawings will be returned

to the manufacturer with indication of review corrections. Where

a correction is required, two sets of revised prints shall be

resubmitted to the owner. These prints shall be marked "Revised"

and dated.

7.2.2 Final fabrication drawings for each different framing

pattern and pole calculations for each load case shall be

submitted to and approved by the owner before release of order

for manufacture.
Bulletin 1724E-216

Page 22

7.2.3 All design and detail drawings shall be reviewed and

approved by the owner before pole manufacture.

7.2.4 Information to be Provided on Drawings: The manufacturer

shall be responsible for the correctness of dimensions and

details on the drawings. The review of such drawings by the

owner shall not relieve the manufacturer of this responsibility.

Drawing titles shall clearly indicate the owner's name and poletype identification. Each detail drawing shall include the

following minimum information:

a. Complete dimensional information;

b. Description and location of all steel reinforcements,

and, if dropout system is used, the location of each

steel cable dropout;

c. Twenty-eight day strength of concrete and strength of

concrete at time of release of pretensioning strands;

d. Steel strand prestress loads;

e. Size, description, quantity, and location of all holes

and hardware that is a part of the pole;

f. Weight and location of the center of gravity of the

pole;

g. Location of pickup points and storage points. Both

pickup locations and recommended storage locations shall

be shown;

h. Location of climbing devices and grounding inserts;

i. Pole identification plate location and details;

j. Location of groundline;

k. The ultimate moment and cracking moment capacities at

the groundline; and

l. Any other special information deemed necessary by the

manufacturer and owner.

8. APPROVALS, ACCEPTANCE, AND OWNERSHIP

8.1 Final designs must be approved by the owner before material

ordering. Material ordering and fabrication prior to approval of
Bulletin 1724E-216

Page 23

the owner will be at the manufacturer's risk. Award of the

contract to the manufacturer does not constitute acceptance of

design calculations submitted with the bid. If corrections are

required in the final pole designs due to manufacturer's errors,

omissions, or misinterpretations of the specifications, the

quoted price shall not change. Approval of the drawings and

calculations by the owner does not relieve the manufacturer of

responsibility for the adequacy of the design, correctness of

dimensions, details on the drawings, or the proper fit of parts.

8.2 Upon delivery, poles shall be free of defects and blemishes

which would have a detrimental effect on the structure capacity

and/or longevity of the pole. They also shall be smooth,

attractive, unscarred and in new condition. Poles not meeting

these requirements shall be repaired or replaced by the

manufacturer at no additional cost to the owner.

8.3 Poles failing to meet strength requirements, poles with

circumferential or longitudinal cracks, poles failing to meet

manufacturing tolerances or cover requirements, poles with

exposed steel, poles with cavities that absorb water, and spliced

poles that do not fit together properly or are distorted after

mating shall be rejected by the owner and replaced by the

manufacturer at no cost to the owner.

8.4 If the delivered weight of a pole will exceed the calculated

weight by 5 percent, the manufacturer shall notify the owner of

the actual weight before pole delivery. Any pole whose delivered

weight exceeds or is below 10 percent of its calculated weight

may be rejected by the owner.

8.5 All final drawings shall become the property of the owner,

who shall have full rights to reproduce and use them, but shall

not share them with other concrete pole suppliers.

9. LIST OF ATTACHMENTS

(Attachments A and B to be co}pleted by the engineer.

Attachment C to be completed by the manufacturer.)

• Attachment A, Pole Framing Drawings

• Attachment B, Application Requirements

• Attachment C, Bid Summary
Bulletin 1724E-216

Page 24

BLANK PAGE
Bulletin 1724E-216

Page 25

ATTACHMENT A

DRAWINGS

(Drawings to be added by owner)
Bulletin 1724E-216

Page 26

BLANK PAGE
Bulletin 1724E-216

Page 27

ATTACHMENT B

Application Requirements

For appurtenance material supplied by the owner, owner shall

provide manufacturer, connector and/or member locations,

orientations, sizes, types, and strength capacities with this

Attachment.

1. Climbing device desired by owner _________

2. Delivery schedule _________

3. Free on board destination (F.O.B.) _________

4. Additional requirements (below)
Bulletin 1724E-216

Page 28

BLANK PAGE
Bulletin 1724E-216

Page 29

ATTACHMENT C

DESIGN INFORMATION 

STRUCTURE DESIGNATION

POLE LENGTH

BOTTOM DIAMETER

GROUNDLINE DIAMETER

TOP DIAMETER

WALL THICKNESS -BUTT

WALL THICKNESS - TIP

TOP PRESTRESSING STEEL

 NUMBER OF STRANDS

 SIZE OF STRANDS

BOTTOM PRESTRESSING STEEL

 NUMBER OF STRANDS

 SIZE OF STRAND

DROP LOC. OF STRANDS (FROM BUTT)

POLE TOP DEFLECTION @ FULL TIP LOAD

POLE TOP DEFLECTION @ 40% TIP LOAD

28 DAY COMPRESSIVE STRENGTH

DIAMETER TAPER ( IN/FT)

DESIGN LOADS

MAX. REACTIONS AT GROUNDLINE 

 MOMENT

 SHEAR

 AXIAL

MAX. REACTIONS AT POINT OF FIXITY 

 MOMENT 

 SHEAR

 AXIAL

SUMMARY

WEIGHT OF POLE

TOTAL COST PER POLE

NUMBER OF POLES

TOTAL COSTS

COMMENTS

Attach sheets to provide information TRANSMISSION LINE POLES

required every five foot interval. ATTACHMENT C 

See sections 7.1.b and 7.1.c. BID SUMMARY - DESIGN INFORMATION, WEIGHTS, AND 

of the specifications. PRICE INFORMATION

 (INFORMATION TO BE SUPPLIED

 WITH THE PROPOSAL)
Bulletin 1724E-216

Page 30

BLANK PAGE
Bulletin 1724E-216

Page A-1

APPENDIX A

COMMENTARY

A. General

The necessity of a clear bid specification for the purchase of

standard class concrete poles is very important to the bid

evaluation process and the acquisition of structurally adequate

poles. The specification should contain sufficient requirements

and information so that all bids can be evaluated equally and so

that the manufacturer clearly understands what is expected of the

manufacturer.

Scope

While this standard class concrete pole specification does not

prohibit the application to poles which are guyed, which are

subjected to unbalanced lateral loads, or which have deflection

or other special limitations, the owner must be prudent in this

type of application.

It is recognized that, with the proper understanding and usage of

some computerized structural analysis and transmission line

design programs, it is possible to select a standard class

concrete pole which might otherwise be beyond the scope of this

specification. The owner must be sure that combined bending and

buckling analysis is performed, that cracking strength and zero

tension strength is evaluated, and that deflections are properly

modeled.

The owner should recognize when the design of a concrete pole may

be more prudently accomplished using the Guide Specification for

Spun, Prestressed Concrete Pole and Concrete Pole Structures, RUS

Bulletin 1724E-206, which requires the actual loading conditions

to be specified. In using Bulletin 1724E-206, the manufacturer

assumes full responsibility in designing and manufacturing a

structurally adequate pole.

Standard Class Pole

In some cases, utilities prefer to specify certain spun concrete

poles to be designed according to a standardized loading

criteria, much like the standard classifications for wood poles.

In utilizing standard class spun concrete poles, a complete

structural analysis is still required for all structures. All

appropriate loading criteria are considered in the analysis. Once

the required concrete pole strength is determined, a standard

class spun concrete pole which meets the actual loading
Bulletin 1724E-216

Page A-2

conditions can be selected. A design example is shown in

Appendix C.

This specification was developed to establish a standard

classification system and to assist the owner in procuring a

standard class concrete pole which is properly designed for the

intended loading criteria.

This guide specification attempts to eliminate ambiguity in

specifying and purchasing standard class concrete poles. Since it

has become a widespread practice in the industry to design and

manufacture poles which are based on the wood pole classification

system of the American National Standards Institute (ANSI 05.1),

the concrete pole classifications developed in this specification

generally follow the wood pole classification system. However, to

avoid confusion with the wood pole classifications, the concrete

pole classifications have a unique naming system.

Wood Pole Equivalency

In some cases, the owner may design a transmission line based on

wood pole classifications as described in ANSI 05.1, Wood Pole

Specifications and Dimensions, and then wish to order concrete

poles which meet the wood pole equivalent loadings. Because of

the differences in overload factors applied to wood poles in

comparison to concrete poles, the owner must be sure that the

overload factors are properly accounted for in the design of the

concrete poles.

“Wood pole equivalent” is a term that may be defined in a number

of ways. For purposes of this commentary, the term “wood pole

equivalent” is defined as a standard class prestressed concrete

pole which is equated by required ultimate loading to an ANSI

05.1 standard class wood pole. The equation is made by a ratio of

the overload factors applicable for each pole type and loading

criteria.

The design and purchase of concrete poles as an equivalent to

wood poles can be vague even with clear instructions. As such,

the owner should be sure that the equivalency is properly

determined. Once the equivalency is determined, the owner should

specify the standard class concrete pole based on the

classifications detailed in Section 4.1.2. In doing this, the

manufacturer will not be involved in the equivalency process and

the ambiguity should be eliminated.

The wood pole equivalency is based on the required ultimate

moment capacity of the pole at the groundline based on embedment

depths shown in ANSI 05.1. In obtaining a suitable equivalency,

the owner must consider factors other than the equivalent
Bulletin 1724E-216

Page A-3

groundline moment. For example, the differences in material and

section properties of the wood pole versus the concrete pole will

result in differences in buckling analysis, pole deflections,

secondary moments, applied wind forces, and so forth.

It is impossible to completely equate the concrete pole and wood

pole at all points along the pole. The owner must be certain that

the concrete pole selected by equivalency methods will have a

strength sufficient for the actual application.

Equivalency Factor (Eq.F)

The equivalency factor (Eq.F) is defined as the ratio of the

concrete pole overload factor to the wood pole overload factor

for a given loading condition.

For example, for NESC Grade B district wind loading, the concrete

pole overload factor is 2.5 and the wood pole overload factor is

4.0. Thus, the equivalency factor will be 2.5/4.0 = 0.625.

The equivalency factor is a useful concept to understand as the

owner requires a wood pole equivalent under various loading

conditions and overload factors. Several examples of

equivalencies are listed in the following sections.

Wood Pole Equivalency - 2.5:4 Ratio (0.625 Eq.F)

For the NESC Grade B district loadings, the NESC allows for an

overload factor of 2.5 to be applied to a transverse wind load on

a concrete pole while it requires an overload factor of 4.0 to be

applied to a transverse wind load on a wood pole. As such, the

ultimate strength requirement for the concrete pole will be less

than the ultimate strength of the wood pole for the district wind

loading conditions.

For example, the owner designs a transmission line for wood poles

based on NESC district wind loading conditions. The owner wishes

to purchase a concrete pole which is equivalent to a Class 1 wood

pole. Based on ANSI 05.1, the Class 1 wood pole groundline

strength is derived by applying a horizontal ultimate load of

4,500 pounds at 2' from the pole tip based on a simple

cantilever. Since the owner had classed the wood pole based on an

NESC overload factor of 4.0, the owner wishes to select a

concrete pole meeting the same NESC district wind loading

conditions. To do this, the owner will multiply the required tip

loading of 4,500 pounds by 2.5/4.0, which equals 2,812 pounds.

The 2.5/4.0 ratio (or 0.625 Eq.F) adjusts for the difference

between wood and concrete overload factors for NESC district

loads. The owner will then select a standard class concrete pole

which has an ultimate moment capacity based on the horizontal tip
Bulletin 1724E-216

Page A-4

loading of at least 2,812 pounds. From Section 4.1.2, the owner

selects a class C-02.8 pole, which has a tip loading of 2,825

pounds.

Based on the method shown in this example, Table A-1 (at the end

of this section) is a tabulation of wood pole equivalencies based

on the NESC Grade B district wind loading.

Wood Pole Equivalency - 1.1:1.5 Ratio (0.733 Eq.F)

For the NESC Grade B extreme wind loadings, this specification

requires an overload factor of 1.1 to be applied to a transverse

extreme wind load on a concrete pole. RUS recommends an overload

factor of 1.5 to be applied to a transverse extreme wind load on

a wood pole. As such, the ultimate strength requirement for the

concrete pole will be less than the ultimate strength of the wood

pole for the NESC extreme wind loading conditions.

For example, the owner designs a transmission line for wood poles

based on NESC extreme wind loading conditions. The owner wishes

to purchase a concrete pole which is equivalent to a Class 1 wood

pole. Based on ANSI 05.1, the Class 1 wood pole groundline

strength is derived by applying a horizontal ultimate load of

4,500 pounds at 2' from the pole tip based on a simple

cantilever. Since the owner had classed the wood pole based on an

NESC extreme wind overload factor of 1.5, the owner wishes to

select a concrete pole meeting the same extreme wind loading

conditions. To do this, the owner will multiply the required tip

loading of 4,500 pounds by 1.1/1.5, which equals 3,300 pounds.

The 1.1/1.5 ratio (or 0.733 Eq.F) adjusts for the difference

between wood and concrete extreme wind overload factors. The

owner will then select a standard class concrete pole which has

an ultimate moment capacity based on the horizontal tip loading

of at least 3,300 pounds. From Section 4.1.2, the owner selects a

class C-03.4 pole, which has a tip loading of 3,375 pounds.

Based on the method shown in this example, Table A-2 at the end

of this section is a tabulation of wood pole equivalencies based

on the NESC Grade B extreme wind loading. 

Wood Pole Equivalency - 1:1 Ratio (1.0 Eq.F)

Occasionally, the owner may wish to order a concrete pole which

has the same ultimate strength as a specified wood pole class.

One common application of this is when the owner designs a

transmission line using wood pole properties, but utilizing

concrete pole overload factors. In this case, the owner has

accounted for the difference in wood versus concrete overload

factors during the design of the project.
Bulletin 1724E-216

Page A-5

For example, the owner designs a transmission line for wood poles

based on NESC district wind loading conditions. However, knowing

that concrete poles will be utilized, the owner uses the NESC

district wind load overload factor of 2.5 (applicable to concrete

poles) in the calculations. The owner selects a wood pole Class 1

at a specific location. Thus, the owner wishes to purchase a

concrete pole which is equivalent in ultimate strength to a Class

1 wood pole. Based on ANSI 05.1, the Class 1 wood pole groundline

strength is derived by applying a horizontal ultimate load of

4,500 pounds at 2' from the pole tip based on a simple

cantilever. Therefore, the owner will require a concrete pole

with an ultimate moment capacity based on the same 4,500 pound

tip loading. From Section 4.1.2, the owner selects a Class C-04.7

concrete pole, which has a tip loading of 4,700 pounds.

Based on the method shown in the this example, Table A-3 at the

end of this section is a tabulation of wood pole equivalencies

based on the ultimate-to-ultimate strength comparison, or 1.0

equivalency factor. 

Other Wood Pole Equivalencies

Using the wood pole equivalency methods described, the owner can

develop equivalency tables for other ratios of wood versus

concrete overload factors.

For example, the design of a heavy angle or deadend transmission

line structure may be predominantly controlled by the conductor

tension rather than wind on the wire. The NESC specifies an

overload factor of 1.65 to be applied to concrete pole wire

tensions and an overload factor of 2.0 to be applied to wood pole

wire tensions. The resulting equivalency ratio would be 1.65/2.0,

or an equivalency factor of 0.825. From a review of the tables at

the end of this section, Table A-2 has an equivalency factor of

0.733 while Table A-3 has an equivalency factor of 1.0. Rather

than developing a new equivalency table for this special

application, the owner might prefer to select a concrete pole

equivalency based on the Table A-3 which has an equivalency

factor greater than the required factor of 0.825.

Conclusions concerning wood pole equivalencies – The designer may

avoid the confusing concept of wood pole equivalency by using the

procedure below to select the standard class pole from Table 2:

• Calculate the induced design moment in the pole from applied

loads with overload factors.

• Determine the equivalent tip load for this moment.

• Select the pole from the standard class pole from Table 2 of

the Specifications
Bulletin 1724E-216

Page A-6

TABLE A-1

WOOD POLE EQUIVALENCY

BASED ON 2.5:4 RATIO

 (0.625 Equivalency Factor)

(NESC Grade B District Wind Loading)

(Equivalencies based on approximate groundline strength)

Design

Wood Pole Class

Based on 4.0 OCF

Select

Concrete Pole Class

Based on 2.5 OCF

H6 C-07.1

H5 C-06.2

H4 C-05.4

H3 C-04.7

H2 C-04.0

H1 C-03.4

1 C-02.8

2 C-02.3

3 C-01.9

TABLE A-2

WOOD POLE EQUIVALENCY

BASED ON 1.1:1.5 RATIO

(0.733 Equivalency Factor)

(NESC Grade B Extreme Wind Loading)

(Equivalencies based on approximate groundline strength)

Design

Wood Pole Class

Based on 1.5 OCF

Select

Concrete Pole Class

Based on 1.1 OCF

H6 C-09.0

H5 C-08.0

H4 C-07.1

H3 C-05.4

H2 C-04.7

H1 C-04.0

1 C-03.4

2 C-02.8

3 C-02.3
Bulletin 1724E-216

Page A-7

TABLE A-3

WOOD POLE EQUIVALENCY

BASED ON 1:1 RATIO

(1.0 Equivalency Factor)

(Ultimate-to-Ultimate Comparison)

(Equivalencies based on approximate groundline strength)

Design

Wood Pole Class

Select

Concrete Pole Class

H6 C-12.0

H5 C-10.0

H4 C-09.0

H3 C-08.0

H2 C-07.1

H1 C-05.4

1 C-04.7

2 C-04.0

3 C-03.4

B. Section 4. Design

Loads (Section 4.1)

The primary loads for concrete poles are weather and erection

loads. Common handling loads are determined by the manufacturer

and included in the manufacturer’s design. Weather, construction

and maintenance loads need to be determined by the owner in order

to select the proper standard class pole.

Overload factors for NESC light, medium, and heavy loading

districts should be at least equal to those given in the

applicable edition of NESC for Grade B construction. Overload

factors for extreme ice and extreme wind should be at least 1.1.

In addition to using the NESC district loading requirements, the

ASCE publication, “Guidelines for Transmission Line Structure

Loading” can be used to provide owners with procedures for the

selection of design loads and load factors related to climate,

accidents, construction and maintenance.

Once the design loadings have been determined, a design of the

structure should be performed by the owner’s engineer or

structural designer. It is recommended that a nonlinear

structural analysis computer program be utilized to consider the
Bulletin 1724E-216

Page A-8

loadings, secondary moments (p-delta effect), and effects of

foundation rotations and deflections. As a minimum, an

approximate method for determining the ultimate moment capacity

should be utilized, such as the methods given in RUS Bulletin

1724E-200, Design Manual for High Voltage Transmission Lines.

Once the structural analysis has been completed, the owner’s

engineer or structural designer may select a standard class

concrete pole, which has the ultimate moment capacity greater

than the design loading requirements. Consideration should be

given for strength requirements at all points along the pole, not

just at the groundline.

P-Delta Moment

Prior to selecting a standard class concrete pole, the owner

should determine the effect of the secondary moments due to the

vertical loadings, including the effect of the pole weight,

during the transmission line design process.

Whenever there is a transverse or longitudinal load, the pole

will deflect in the direction of the load. As a result, the

vertical load is no longer in its original position. The

vertical load moves over as the pole deflects, causing additional

moments in the pole. Also, the pole weight can place significant

secondary moment loads in the pole. The additional stress caused

by this secondary moment is dependent on the magnitude of the

vertical load and deflected shape of the pole. Many pole

designs, particularly tall poles, have to be calculated for the

position of equilibrium of forces in the fully displaced

position. The solution typically takes many iterations. A full

nonlinear analysis will consider the change in orientation of the

loads relative to the displaced positions of the structural

members.

As a minimum, an approximate method for determining the effect of

the secondary moments should be utilized, such as the method

given in the RUS Bulletin 1724E-200.

Pole Tip Strength (Section 4.1.2)

This specification sets minimum ultimate moment capacity

requirements near the pole tip for each standard pole

classification. The similar ANSI 05.1 requirement is generally

overlooked, misunderstood or not considered by manufacturers and

others who seek to standardize pole sizes based on the wood pole

classification.

Upon a careful study of the ANSI 05.1 wood pole specification,

one should understand that the horizontal loading applied at 2'
Bulletin 1724E-216

Page A-9

from the pole tip is for the purpose of determining a required

groundline ultimate moment capacity for any length pole of the

given class. However, the minimum required wood pole tip size is

specified apart from the horizontal loading requirement

For example, according to ANSI O5.1, a Class 1 wood pole must

have a circumference of 27" at the tip. When applied to the

Douglas Fir or Southern Yellow Pine poles with a fiber stress of

8,000 psi, the resulting tip strength is calculated as 41.5 ftkips for the Class 1 wood pole.

Because the conductors and shield wire supports are typically

located on crossarms away from the pole axis, significant moments

can be generated in the pole near the tip. The moments are

greatly increased whenever a braced pole top assembly is

utilized. These moments are not accounted for by applying the

horizontal ultimate loading alone. Therefore, in the design of

transmission poles, it is critical that a minimum ultimate moment

capacity be specified near the pole tip. In the absence of a

minimum tip strength requirement, a concrete pole tip strength

can theoretically be negligible.

The minimum pole tip strength required by this specification

should be suitable for most transmission line applications.

However, the owner must be sure that the tip strength is properly

evaluated, especially when working with wood pole equivalencies

and braced structures.

Point of Fixity (Section 4.1.2)

Point of fixity for this specification is defined as the location

on the pole where maximum moment occurs. Maximum moment is

calculated by the pole designer using the loadings provided by

the owner and multiplying those loadings by the appropriate

moment arms. The existing soil and backfill has to be able to

support the pole with these bending moments applied. The

location of this point of fixity could be at or below the

groundline. The exact location is theoretical and depends on the

soil condition and backfill used to support the pole.

For the standard class pole, the point of fixity should remain at

the same location on the pole, regardless of the embedment depth

the owner may specify for a given application. Otherwise, the

required pole strength could vary as the location of the point of

fixity varies. Within the scope of this standard class pole

specification, the point of fixity is arbitrarily considered to

be located at a distance from the pole butt, which is equal to 7%

of the pole length. This value seems to work quite well over a

range of pole lengths and is approximately the same value as a

point of fixity located at 1/3 of the distance below the
Bulletin 1724E-216

Page A-10

groundline based on an embedment depth of 10% of the pole length

+ 2'.

The reinforcing steel required at the point of fixity is required

to continue to the pole butt. However, due to the loss of

prestressing steel strength near the pole butt, the ultimate

moment capacity near the pole butt will be reduced.

Tip Loading (Section 4.1.2)

The tip loading is used to develop a required ultimate moment

capacity diagram at any point along the pole from 2' below the

pole tip down to the point-of-fixity. This ultimate moment

capacity is determined by multiplying the tip load by the moment

arm based on a simple cantilever. As a result, the required

ultimate moment diagram is linear in shape. This same method may

be utilized in structural analysis and automated transmission

line design computer programs to develop an array of ultimate

moment requirements for standard concrete pole sizes.

Pole Deflection (Section 4.1.3 and 4.1.4)

Although significant horizontal pole deflection limitations are

considered to be beyond the scope of this standard class concrete

pole specification, some allowances can be made for these

effects. They should be considered during the analysis of the

actual loading conditions applied to the concrete pole.

Typically, this type of analysis should be accomplished by

nonlinear structural analysis techniques. Since the electrical

clearances must be assured in the operation of transmission

lines, deflections must remain within an acceptable range.

This specification limits the allowable pole deflection to 15% of

the pole height above the point of fixity when the tip load

specified in Section 4.1.2 is applied under a horizontal testing

procedure under short term loading conditions. Long term loading

will cause continued deflection due to the plastic deformation of

the concrete.

The owner should recognize that the actual pole deflection for an

application will be less than the specified deflection limit of

15% of the pole height. With the standard class pole, all of the

loading is applied near the pole tip. In a typical transmission

line application, the actual horizontal loading will be some

distance from the pole tip. As such, the actual deflection at the

conductor under short term ultimate loading conditions can be

expected to be less than 10% of the height above ground.

This specification also limits the allowable pole deflection to

5% of the pole height above the point of fixity when 40% of the
Bulletin 1724E-216

Page A-11

tip load specified in Section 4.1.2 is applied under a horizontal

testing procedure under long term loading conditions. This 40%

loading approximates the unfactored NESC loading conditions as is

discussed in the commentary on cracking strength.

The NESC requires that electrical clearances be maintained under

a wind loading of 6 psf. It is expected that the deflection of a

standard class pole under this 6 psf loading condition will be

less than 3% of the height above ground.

For situations where the owner wishes to know the deflection for

a standard class pole, the owner should use a suitable structural

analysis computer program in which the actual design loading

conditions and concrete pole properties are input into the

program. Another option would be to ask the pole manufacturer to

provide the analysis.

If the owner has special deflection limitations, it is

recommended that RUS Bulletin 1724E-206, Guide Specification for

Spun, Prestressed Concrete Pole and Concrete Pole Structures, be

utilized instead of this specification. In doing so, there will

be little doubt as to what the actual pole deflections will be

under all loading conditions.

Cracking Strength (Section 4.1.5)

Cracking strength is defined as the point at which the concrete

just begins to separate due to exceeding the tensile strength of

the concrete on the tension face of the pole.

To minimize the potential for corrosion of the reinforcing steel,

it is desirable to avoid cracking under the unfactored NESC

district loading conditions, or any other service loads specified

by the owner. Under this standard class concrete pole

specification, these service loads are not specified, but are

considered to be 40% of the specified ultimate loads.

For concrete poles designed within the limits of this

specification, the predominant pole loading will be transverse

wind loads. The service load is determined based on the ratio of

the transverse overload factor. The NESC overload factor applied

to district wind loads is 2.5. As such, the service load will be

equal to the ultimate load divided by 2.5, or 40% of the ultimate

load.

For typical concrete pole designs, initial cracking occurs at

about 40-55 percent of the ultimate strength of the pole.

Therefore, the requirement for the cracking strength to be at

least 40% of the required ultimate strength should not cause the

pole to be stronger than when considering ultimate strength

alone.

Since it may be theoretically possible to have a cracking
Bulletin 1724E-216

Page A-12

strength at less than 40% of the ultimate strength, it is not

desirable to do so. By requiring the cracking strength to exceed

40% of the required ultimate strength, the owner is assured of an

adequate cracking strength for the standard class concrete pole.

Zero Tension Strength (Section 4.1.6)

The zero tension strength is defined as the moment at which a

crack that was previously created by exceeding the cracking

moment strength will open again. Under this condition, an applied

moment will not cause any tensile stress in the concrete.

It is important to avoid open cracks in situations of significant

unbalanced lateral loading and in extremely corrosive

environments in order to protect the steel reinforcing. Typical

structures with permanent unbalanced lateral loads are unguyed

angle and unguyed deadend structures. While the design of these

structure types is generally outside the recommended scope of

this specification, this specification does require a minimum

zero tension strength for all pole classes.

It has been demonstrated that the zero tension strength will

typically be 70% to 85% of the cracking strength. With a minimum

cracking strength of 40% of ultimate, 70% of this value would be

equal to 28% of ultimate. Thus, it is natural for all spun

concrete poles to have a zero tension strength of at least 28% of

ultimate. As such, this specification requires the standard class

concrete pole to have a zero tension strength exceeding 28% of

the required ultimate strength.

For situations where the owner wishes to select a standard class

pole based on a minimum zero tension strength, this specification

may be utilized. A typical situation where the owner may wish to

do this is when the owner uses a transmission line design

computer program in which zero tension strength values are input

for each pole type.

The owner should recognize that the zero tension strength for

most concrete poles is greater than the minimum required strength

of 28% of the ultimate strength. In fact, the zero tension

strength can be as high as 50% of the ultimate strength. Thus,

for concrete pole applications which must be designed for the

zero tension strength requirements, such as unguyed or unbalanced

lateral loadings, it is quite possible for the owner to obtain

the concrete pole at a significantly lesser cost by submitting

the actual loading conditions to the manufacturer using RUS

Bulletin 1724E-206.
Bulletin 1724E-216

Page A-13

Foundation Rotation and Deflection

Although significant foundation rotation and deflection criteria

are considered to be beyond the scope of this standard class

concrete pole specification, some allowances can be made for

these effects. They should be considered during the owner’s

analysis of the actual loading conditions to apply to the

concrete pole. Typically, this type of analysis is accomplished

by nonlinear structural analysis techniques.

Once the structural analysis has been completed (including

foundation rotations and deflections, p-delta effect, etc.), the

owner may select a standard class concrete pole which has the

ultimate moment capacity greater than the design loading

requirements.

Longitudinal Loads

It is recommended that RUS Bulletin 1724E-206 be utilized

whenever the longitudinal loads may result in a significant

unbalanced lateral loading condition. In this case, the design of

the structure based on zero tension strength is emphasized.

(Refer to the Commentary regarding Zero Tension Strength.)

Because concrete poles are flexible structures, there may be a

reduction in induced moments in a pole under some types of

longitudinal loads due to the restraining effect of the overhead

ground wires. Traditionally, static longitudinal loads are

specified due to the complexity of calculating the influence of

structure flexibility.

Guy Wires

It is generally beyond the scope of this standard class concrete

pole specification to consider guy wires in the design of the

structure. It is recommended that RUS Bulletin 1724E-206 be

utilized instead.

However, a typical situation where the owner may wish to use this

specification for guyed poles is when the owner uses a

transmission line design computer program, or other structural

analysis program, in which minimum strength values are input for

each pole type and the program is capable of combined bending and

buckling analysis of guyed concrete poles.

It may also be possible to specify certain types of guyed
Bulletin 1724E-216

Page A-14

concrete poles based on wood pole analysis techniques as detailed

in RUS Bulletin 1724E-200. Once the wood pole class is

determined, a standard class concrete pole could be selected

based on an equivalency. In this case, it is recommended that the

1:1 equivalency ratio be utilized. It is generally agreed that a

concrete pole has a greater buckling strength than an

equivalently classed wood pole; therefore, the selected concrete

pole class should be adequate for a situation in which a wood

pole would normally be specified. The owner should use caution in

using this equivalency method and its usage should be prudently

influenced by the owner’s experience in similar applications

where actual design loadings were utilized under similar guying

conditions.

Any time a concrete pole structure is guyed, the guy type, size,

modulus of elasticity and guy slope or angle has to be determined

by the owner and properly modeled in the analysis of the concrete

structure. As is required by RUS Bulletin 1724E-206, the load in

the guy wire should be limited to 65 percent of its ASTM rated

breaking strength under actual ultimate loading conditions. The

concrete pole and guy wire(s) must be designed as a system.

The guy modulus of elasticity can increase from a minimum value

at the time of manufacture, to a maximum value, which results

from periodic stretching and relaxing during the load cycles.

Ranges from 19,000 ksi to 28,000 ksi have been stated. The ASCE

steel pole specification (ASCE Manual 72) has suggested a guy

wire modulus of elasticity of 23,000 ksi be used by the engineer

whenever it is not specified.

Groundline

The location of the groundline for the standard class pole should

be specified on the owner’s drawings.

While the strength of the standard class pole is not effected by

the groundline location, the proper placement of climbing

devices, ground wire clips, cant hole, vent hole, name plate, and

so forth, depends upon the location of the groundline.

In addition, the ultimate moment capacity at the groundline is to

be noted on the manufacturer’s drawings (see Section 7.2.5) and

stamped on the pole name plate (see Section 4.12.1).

Air Entrainment in Spun Concrete Poles (Section 4.2)

Air entrainment in spun concrete poles is similar to air

entrainment in normal concrete except the fabrication processes

of pumping, vibrating, and spinning causes a large percentage of
Bulletin 1724E-216

Page A-15

the entrained air to migrate out of the concrete. The general

effects of air entrainment are to increase workability, decrease

density (unit weight), decrease strength, reduce bleeding and

segregation, and increase durability. For a spun concrete pole,

the spinning process creates a very dense concrete and

counteracts the air entrainment effects. Since pumping occurs

prior to the pole being spun, the air entrainment effects are

present during the fabrication of spun poles. The percentage of

air entrained in a spun concrete pole after it is spun is

unknown. However, it is believed poles that have concrete

containing an air entrainment agent will have a higher void ratio

than those without this agent. The owner has to be aware that as

the percentage of air entrainment increases the concrete strength

decreases.

Grounding (Section 4.5)

All internal reinforcing should be bonded electrically to the

external pole ground wire. This will keep the external ground and

internal reinforcing potential voltage differences lower during

lightning events. There have been reports of step lugs and other

materials embedded in the concrete, near or in contact with the

reinforcing, being dislodged as a result of lightning. Spliced

poles should have reinforcing on each side of the splice bonded

electrically to the external pole ground wire. This should lower

potential voltage differences of embedded material between each

pole section.

C. Section 5.4 Structure Testing

An option is available in the specification for full scale

testing of poles. For a manufacturer, which has been designing

and fabricating concrete poles with the same processes for a good

number of years, the need for testing of a concrete pole is

questionable. Pole testing may be appropriate in cases where

there are unusual requirements, new fabrication techniques or

when new suppliers are used to validate their design.

D. Section 7 Drawings and Information to be Supplied by the

Manufacturer

In order to properly evaluate bids, the specification requires

certain information to be supplied with the bid. This information

may be supplied on the preliminary drawings from the Bidder.

Using the forms in Attachment C will allow quick review of the

information and simultaneous comparison of all bidders'

information.
Bulletin 1724E-216

Page A-16

Blank Page
Bulletin 1724E-216

Page B-1

APPENDIX B

EXAMPLE POLE FRAMING DRAWINGS

EXAMPLE OF APPLICATION REQUIREMENTS



Bulletin 1724E-216

Page B-5

APPLICATION REQUIREMENTS

For appurtenance material supplied by the owner, owner shall

provide manufacturer, connector and/or member locations,

orientations, sizes, types, and strength capacities with this

Attachment.

1.Climbing device desired by owner STEP BOLTS

2.Delivery schedule JAN. 15, 2000

3.Free on board destination (F.O.B.) LEE'S LANDING, FL 

 LAYDOWN AREA NEAR

 PEJMAN SUBSTATION

4.Additional requirements
Bulletin 1724E-216

Page B-6

BLANK PAGE
Bulletin 1724E-216

Page C-1

APPENDIX C

DESIGN EXAMPLE

Example 1: For the TUC-1 pole structure and loading conditions

given below, determine the “standard class concrete pole”:

General information:

Line voltage: 138 kV

Design by: ACME Engineers

Structure type: TUC-1 Concrete Pole Structures

Geometry of the structure and location of loads:

Distance from Pole Top, Ft.

OHGW 0.25

COND-1 7.50

COND-2 17.50

COND-3 27.50

At Gd. Line-assumed 70.00

Pole-End 80.00

Overall pole length is 80 feet. The above dimensions assume a

10.0 foot embedment depth for the concrete pole (using standard

rule for wood poles of 10 percent pole length plus 2 feet). 

Assume top of the pole has a 12 inch diameter, and the groundline

diameter is 30 inches.

Overload Factors (OLFs) used in this example:

For NESC Light, Medium, or Heavy Loading District Loads

Vertical 1.50 Wind on Pole 2.50

Transv. Wind 2.50 Transv. Line Angle 1.65

Longitudinal Loads 1.65

For Extreme Wind Loads 1.10

Conductor and OHGW Data:

OHGW: 3/8”HSS

R.B.S = 10,800 lbs.

138 kV Conductor: Drake (795 26/7 ACSR)

R.B.S = 31,500 lbs.

Vertical Span 900 ft.

Horizontal Span 750 ft.

Line Angle 0 degrees
Bulletin 1724E-216

Page C-2

Load Cases:

Load Case A: NESC Medium District Loads

With an unbalanced longitudinal

Load of 700 lbs. at each

conductor

Load Case B: 80 Mph Extreme Wind Load

(1.1 OCF applied)

Loading Information (summary):

NESC Medium Loading Data

Transverse Vertical

Cond. Tension (kips) lb./ft. lb./ft.

Drake – 138 kV 7.91 .536 1.516

OHGW – 3/8 HSS 2.56 .287 .463

Extreme Wind Loading Data (16 psf)

Transverse Vertical

Cond. Tension (kips) lb./ft. lb./ft.

Drake – 138 kV 6.54 .9091 1.0940

OHGW – 3/8 HSS 1.23 .4800 .2730

Calculate forces and moments at the groundline:

• NESC Medium District Loading

Load Due

to Wind

on Wire

Load Due to

Line Angle

(kips)

Total Transv.

Load W/OCF

(kips)

Moment Arm

Feet

Ultimate

Moments Ft.

kips

@Groundline

OHGW .22 0 0.54 69.75 37.5

COND-1 .40 0 1.01 62.5 62.8

COND-2 .40 0 1.01 52.5 52.8

COND-3 .40 0 1.01 42.5 42.7

Groundline 0.0

 

Totals for Wire Loads 3.57 195.8

Wind on the Pole 1.23 36.8

Moments due to unbalanced vertical Wire Load 8.2

Moment due to deflection for weight of pole and for wires (pdelta moment)(Approximated) 29.1

Moments due to rise of insulators negligible

Total Transverse Shear and

Moments at Groundline 4.78 269.2

For the unbalance longitudinal load, the shear is 2.1 kips and the

longitudinal moment is 121 ft.-kips (.7k @ each cond.)
Bulletin 1724E-216

Page C-3

TOTAL RESULTANT GROUNDLINE MOMENT = 296 ft. kips

• Extreme Wind Load (no longitudinal load)

Similar calculations are performed for the extreme wind load.

TOTAL GROUND LINE MOMENT FOR THE EXTREME WIND LOAD = 324.1 ft. kips

• Conclusions: The Extreme Wind Loading load controls design.

Determine which “standardized” concrete pole design to use:

Distance 2’ from top to groundline = 70’ – 2.0’ = 68'

Load 2’ from the top to cause a 324 ft.-kip moment

 at groundline: = 324 ft-kips/68’ = 4770 lbs.

Based on the above calculated tip load, use a C-04.7 pole

(The strength is within one percent of the required strength)

Perform a quick check to verify the assumed embedment depth using

Bulletin 1724E-205, “Design Guide: Embedment Depths for Concrete

and Steel Poles”.

Example 2: An existing 115 kV single pole line is composed of

Douglas Fir wood poles. In several locations, concrete poles are

to replace wood pecker damaged wood poles. The existing damaged

poles are 80 ft class 1 wood poles with the TUS pole top

assembly. Determine which standard size pole should be used to

replace the wood pole. Extreme wind design load is 16 psf (80

mph). The line is located in the heavy loading district. The

conductor is 795 Drake and the overhead groundwire is 3/8" HSS.

NESC heavy district loads with an overload factor of 4 controlled

the design of the original wood pole line. A quick comparison of

the unit loads for the extreme wind and the NESC heavy district load

with overload factors for concrete, indicates that the NESC heavy

district and not the extreme wind load will control the design of the

concrete pole. Because extreme wind does not control the design, the

engineer may use Table A-1.

Table A-1 indicates that a C-02.8 may be used. However, in order to

account for the additional moment due to deflection from the dead weight

of the heavy concrete pole and the loaded weight of the conductors, the

engineer should select a pole, one class greater in strength from this

table. A standard class C-03.4 should be used.
Bulletin 1724E-216

Page C-4

Example 3: Same as example 2, except the line must sustain 100

mph extreme wind loads.

NESC heavy district loads with an overload factor of 4 controlled

the design of the original wood pole line. A quick comparison of

the unit loads for the extreme wind and the NESC heavy district load

with overload factors for concrete, indicates that the 100 mph extreme

wind load will control the design of the concrete pole (an overload

factor of 1.1 is used for extreme wind loads). Because the extreme wind

load with an overload factor of 1.1 is greater than the NESC district

load with an overload factor of 4.0, extreme wind will control the

design. Table A-2 should be used to select the appropriate pole.

In order to account for the additional moment due to deflection from the

dead weight of the heavy concrete pole and the loaded weight of the

conductors, the engineer should select one pole class up from the table.

A standard class C-04.0 should be selected.

In example 2, calculations for the actual line conditions may actually

show that a C-02.8 may be used to replace the 80 class 1 wood pole. 

Likewise, the engineer might find that a C-03.4 may be adequate for

example 3 if calculations are performed using actual line conditions.
Bulletin 1724E-216

Page D-1

APPENDIX D

SELECTED SI-METRIC CONVERSIONS
Bulletin 1724E-216

Page D-2

APPENDIX D

SELECTED SI-METRIC CONVERSIONS

AREA

 To Convert From To Multiply by 

circular mil (cmil) square meter (m2) 5.067075 E-10

square centimeter (cm2) square meter (m2) *1.000 E-04

square foot (ft2) square meter (m2) *9.290304 E-02

square inch (in2) square meter (m2) *6.451600 E-04

square kilometer (km2) square meter (m2) *1.000 E+06

square mile (mi2) square meter (m2) 2.589988 E+06

FORCE

 To Convert From To Multiply by 

kilogram force (kgf) Newton (N) *9.806650

kip Newton (N) 4.448222 E+03

pound force (lbf) Newton (N) 4.44822

FORCE PER LENGTH

 To Convert From To Multiply By

kilogram force per

meter (kgf/m) Newton per meter (N/m) *9.806650

pound per foot(lb/ft) Newton per meter (N/m) 1.459390 E+01

DENSITY

 To Convert From To Multiply By

pound per cubic inch kilogram per cubic

 (lb/in3) meter (kg/m3) 2.767990 E+04

pound per cubic foot kilogram per cubic

 (lb/ft3) meter (kg/m3) 1.601846 E+01

LENGTH

 To Convert From To Multiply By

foot (ft) meter (m) 3.048 E-01

inch (in) meter (m) *2.540 E-02

kilometer (km) meter (m) *1.000 E+03

mile (mi) meter (m) *1.609344 E+03

*Exact Conversion.
Bulletin 1724E-216

Page D-3

Selected SI-Metric Conversions, Cont.

LOAD CONCENTRATION

 To Convert From To Multiply By 

pound per square kilograms per square

inch (lb/in2) meter (kg/m2) 7.030696 E+02

pound per square kilograms per square

foot (lb/ft2) meter (kg/m2) 4.788026

ton per square kilograms per square

foot (ton/ft2) meter (kg/m2) 9.071847 E+02

PRESSURE

 To Convert From To Multiply By 

kip per square inch

 (kip/in2) Pascal (Pa) 6.894757 E+06

kip per square foot

 (kip/ft2) Pascal (Pa) 4.788026 E+04

Newton per square

meter (N/m2) Pascal (Pa) *1.000

pound per square

 foot (lb/ft2) Pascal (Pa) 4.788026 E+01

pound per square

inch (lb/in2) Pascal (Pa) 6.894757 E+03

BENDING MOMENT

 To Convert From To Multiply By 

kilogram force meter

 (kgf-m) Newton meter (N-m) *9.806650

kip-foot (kip-ft) Newton meter (N-m) 1.355818 E+02

pound-foot (lb-ft) Newton meter (N-m) 1.355818

VELOCITY

 To Convert From To Multiply By 

foot per second(ft/s)meter per second (m/s) *3.048 E-01

kilometer per hour

 (km/h) meter per second (m/s) 2.777778 E-01

mile per hour(mi/h) meter per second (m/s) 4.370300 E-01

meter per hour(m/h) meter per second (m/s) 2.777778 E-04

*Exact Conversion.
Bulletin 1724E-216

Page D-4

BLANK PAGE
Bulletin 1724E-216

Page E-1

APPENDIX E

CONTRIBUTORS

The following members of the Transmission Line Subcommittee of the

National Rural Electric Cooperative Association, Transmission and

Distribution Engineering Committee provided invaluable assistance in

preparing this document.

Ballard, Dominic, East Kentucky Power Coop., Winchester, KY

Burch, John, Florida Keys Electric Coop., Tavernier, FL

Emmons, Doug, Hoosier Energy REC, Bloomington, IN

Heald, Donald, U.S.D.A, Rural Utilities Service, Washington, D.C.

Hetherington, Bill, Lee County Electric Coop., North Fort Myers, FL

Goodman, Dean, Arkansas Electric Coop., Little Rock, AR

Lukkarila, Charles, United Power Association, Elk River, MN

McCall, Charles, Georgia Transmission Company, Tucker, GA

Oldham, Robert, Southern Maryland Electric Coop., Hughesville, MD

Smith, Art, Patterson & Dewar Engineers, Decatur, GA

Turner, David, Lower Colorado River Authority, Austin, TX

Twitty, John, Alabama Electric Coop., Andalusia, AL