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.

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.

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 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.