How to Specify a Spun Concrete Pole

A spun concrete pole, like any pole supporting conductors, has various loads applied by line tension, changes of line direction, wind, and ice loadings if applicable, on both the conductors and the pole itself. Because of their durability and reliability, spun concrete poles have a favorable load factor specified in ANSI transmission and distribution line requirements. When specifying poles for distribution and transmission use, it is common to select a pole based on tip load requirements or by design.

Tip Load

Concrete poles are grouped in alphabetically labelled classes which have a bending capacity appropriate to the design requirements. The class is defined in terms of a guaranteed minimum ultimate transverse load applied 2 feet down from the tip of the pole.

The ground line moment capacity depends on the length of the pole since that moment is the product of the class minimum ultimate transverse load and the distance between the point of application (2 feet from the tip) and the ground line.

Note, the wood classification system is based on an average strength where the concrete pole class is based on minimum strength, so the two classification systems cannot be directly compared.

Concrete Pole ClassMinimum Ultimate Transverse Load (lbs)
C1200
D1500
E1900
F2400
G3000
H3700
J4500
K5400
L6400
M7500
N8700
O10000

Design Based

The strength of a concrete pole is defined as a minimum strength which does not vary over time. Poles are designed and manufactured so that all poles will exceed the specified minimum strength which will be present for the life of each pole. In contrast, because wood is a naturally grown product with natural defects such as splits and knots, strength is defined as the average strength of all poles of that species and dimension at the time of installation. Since some poles in a batch will have strengths less than the average and because there is further deterioration with time, a strength factor is utilized.

The NESC has determined the strength factor for concrete as 1.0 compared to 0.65 and 0.85 for wood in Grade B and Grade C construction, respectively.  This strength factor is especially important when converting wood poles to spun concrete poles so that the wood pole is replaced with a concrete pole that is designed to the appropriate strength.

For higher voltage lines with large conductor spacings and multiple circuits, there may be major reactions distributed over a substantial length of the pole. There may also be many different load combinations along a line, depending on pole spacing and line angles.

For these types of applications, it is typical to specify poles with a load tree for each pole loading variation along the line. This can be specified by the customer or determined by StressCrete using multiple elevations at which loads can be applied so that the required capacity of the pole can be accurately computed along its entire length.

Pole Specification Chart

SPUN CONCRETE POLESWood Poles
Catalog CodePole Length (ft.)Above Grade Height (ft.)Burial Depth (ft.)*Tip Diameter (in.)**Butt Diameter (in.)Nominal Weight (lbs)Concrete Pole ClassConcrete Pole Min. Ultimate Class Transverse Load (lbs)Approx. Wood Pole ClassApprox. Wood Pole Equivalent Min. Ultimate Transverse Load (lbs)***
E300-CPR-G30'25'5'6.5"11.9"2040C120051235
E300-DPR-G30'25'5'6.5"11.9"2040D150041560
E300-EPR-G30'25'5'6.5"11.9"2040E190031950
E300-FPR-G30'25'5'6.5"11.9"2075F240022405
E350-CPR-G35'29' 6"5' 6"6.5"12.8"2545C120051235
E350-DPR-G35'29' 6"5' 6"6.5"12.8"2545D150041560
E350-EPR-G35'29' 6"5' 6"6.5"12.8"2545E190031950
E350-FPR-G35'29' 6"5' 6"6.5"12.8"2590F240022405
E400-CPR-G40'34'6'6.5"13.7"3095C120051235
E400-DPR-G40'34'6'6.5"13.7"3095D150041560
E400-EPR-G40'34'6'6.5"13.7"3095E190031950
E400-FPR-G40'34'6'6.5"13.7"3150F240022405
E450-DPR-G45'38' 6"6' 6"6.5"14.6"3695D150041560
E450-EPR-G45'38' 6"6' 6"6.5"14.6"3695E190031950
E450-FPR-G45'38' 6"6' 6"6.5"14.6"3760F240022405
E450-GPR-G45'38' 6"6' 6"8.25"16.35"4820G300012925
E500-DPR-G50'43'7'6.5"15.5"4340D150041560
E500-EPR-G50'43'7'6.5"15.5"4380E190031950
E500-FPR-G50'43'7'6.5"15.5"4455F240022405
E500-GPR-G50'43'7'8.25"17.25"5610G300012925
E500-HPR-G50'43'7'8.25"17.25"5650H3700H13510
E550-DPR-G55'47' 6"7' 6"6.5"16.4"5030D150041560
E550-EPR-G55'47' 6"7' 6"6.5"16.4"5080E190031950
E550-FPR-G55'47' 6"7' 6"6.5"16.4"5175F240022405
E550-GPR-G55'47' 6"7' 6"8.25"18.15"6450G300012925
E550-HPR-G55'47' 6"7' 6"8.25"18.15"6500H3700H13510
E600-FPR-G60'52'8'6.5"17.3"5935F240022405
E600-GPR-G60'52'8'8.25"19.05"7340G300012925
E600-HPR-G60'52'8'8.25"19.05"7405H3700H13510
E650-FPR-G65'56' 6"8' 6"6.5"18.2"6740F240022405
E650-GPR-G65'56' 6"8' 6"8.25"19.95"8285G300012925
E650-HPR-G65'56' 6"8' 6"8.25"19.95"8360H3700H13510
E700-FPR-G70'61'9'6.5"19.1"7595F240022405
E700-GPR-G70'61'9'8.25"20.85"9275G300012925
E700-HPR-G70'61'9'8.25"20.85"9365H3700H13510
E750-GPR-G75'65' 6"9' 6"8.25"21.75"10320G300012925
E750-HPR-G75'65' 6"9' 6"8.25"21.75"10420H3700H13510
E750-JPR-G75'65' 6"9' 6"8.25"21.75"10565J4500H24160
E750-KPR-G75'65' 6"9' 6"9.5"23"11865K5400H34875
E750-LPR-G75'65' 6"9' 6"9.5"23"12100L6400H45655
E800-GPR-G80'70'10'8.25"22.65"11415G300012925
E800-HPR-G80'70'10'8.25"22.65"11530H3700H13510
E800-JPR-G80'70'10'8.25"22.65"11680J4500H24160
E800-KPR-G80'70'10'9.5"23.9"13080K5400H34875
E800-LPR-G80'70'10'9.5"23.9"13340L6400H45655
E850-GPR-G85'74' 6"10' 6"8.25"23.55"12555G300012925
E850-HPR-G85'74' 6"10' 6"8.25"23.55"12685H3700H13510
E850-JPR-G85'74' 6"10' 6"8.25"23.55"12855J4500H24160
E850-KPR-G85'74' 6"10' 6"9.5"24.8"14345K5400H34875
E850-LPR-G85'74' 6"10' 6"9.5"24.8"14630L6400H45655
E850-MPR-G85'74' 6"10' 6"11.25"24.8"16260M7500H56500
E850-NPR-G85'74' 6"10' 6"13.0"27.3"16605N8700H67410
E900-GPR-G90'79'11'8.25"24.45"13755G300012925
E900-HPR-G90'79'11'8.25"24.45"13890H3700H13510
E900-JPR-G90'79'11'8.25"24.45"14070J4500H24160
E900-KPR-G90'79'11'9.5"25.7"15660K5400H34875
E900-LPR-G90'79'11'9.5"25.7"15970L6400H45655
E900-MPR-G90'79'11'11.25"25.7"17700M7500H56500
E900-NPR-G90'79'11'13.0"28.2"18135N8700H67410
E900-OPR-G90'79'11'14.75"28.2"19870O10000H7†8385
E950-LPR-G95'83' 6"11' 6"9.5"26.6"17360L6400H45655
E950-MPR-G95'83' 6"11' 6"11.25"26.6"19190M7500H56500
E950-NPR-G95'83' 6"11' 6"13.0"29.1"19665N8700H67410
E950-OPR-G95'83' 6"11' 6"14.75"29.1"21495O10000H7†8385
E1000-KPR-G100'88'12'9.5"27.5"18450K5400H34875
E1000-LPR-G100'88'12'9.5"27.5"18805L6400H45655
E1000-MPR-G100'88'12'11.25"27.5"20810M7500H56500
E1050-KPR-G105'92' 6"12' 6"9.5"28.4"19920K5400H34875
E1050-LPR-G105'92' 6"12' 6"9.5"28.4"20300L6400H45655
E1050-MPR-G105'92' 6"12' 6"11.25"28.4"22425M7500H56500
E1100-KPR-G110'97'13'9.5"29.3"21445K5400H34875
E1100-LPR-G110'97'13'9.5"29.3"21850L6400H45655
E1100-MPR-G110'97'13'11.25"29.3"24085M7500H56500

* Burial depths are assumed at 10% of pole length plus 2 feet
** Tip Diameter may vary by design
*** Wood pole equivalents are based upon NESC Grade B District Loading (0.65 Strength Factor). If other design criteria is required, please contact StressCrete to determine the required class. Min. Ultimate Transverse Load calculated at 2 feet from pole tip.
† Extrapolated

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