Custom Search
|
|
POLE GUYS When constructing power lines, you will need a means of strengthening poles and keeping them in position. To accomplish this, you can use guys, anchors, and braces. Anchors are buried in the ground, and guy wires are connected to the anchors and attached to the pole, or a push brace may be used. The guys and braces are used to counter the horizontal strain on the pole caused by conductors, pole-line components, and abnormal loads, such as snow, sleet, or wind. Anchors Anchors are designed to meet specific soil conditions. You must know the type of soil before you can select a certain type of anchor. Anchors come in many forms and have different methods of installation. Figure 4-1 shows the most common types of anchors. The expanding anchor, the most popular type, as shown in figure 4-1, view A, is designed to be placed in the ground and then expanded with the aid of the tamping bar. Once expanded, the anchor is secure and strong enough to secure the guy. Figure 4-1, view B, shows a plate of a never-creep anchor, and view C shows a screw anchor that is installed using an earth auger. These three types of anchors are manufactured and are commonly used because of their ease of installation. Another type of anchor that is shown in figure 4-1, view D, is called a deadman. This anchor is made of a 6- to 8-foot-long piece of treated power pole and an anchor rod. It is installed 6 feet deep in loose or sandy type of soil, with an angle of pull for the guy wire and rod assembly equal to 45 degrees. The deadman is not widely used today because of the time and effort required to place it. Anchor Rods The anchor rod serves as the connecting link between the anchor and the guy cable. The rod must
Figure 4-1.- Anchors. have an ultimate strength equal to, or greater than, that required by the down-guy assembly. Anchor rods vary in diameter from 1/ 2 to 1 1/ 4 inches and in length from 3 1/ 2 to 12 feet. Guy Wire The wire, or cable, normally used in a down guy is seven-stranded galvanized steel wire or seven-stranded alumoweld wire. Alumoweld wire consists of steel wire strands coated with a layer of aluminum to prevent corrosion. Guy wire is used in various sizes with diameters from 1/ 8 to 1 3/ 4 inches. Guys A guy is a brace or cable fastened to the pole to strengthen it and keep it in position. Guys are used whenever the wires tend to pull the pole out of its normal position and to sustain the line during the abnormal loads caused by sleet, wind, and cold. Guys counteract the unbalanced force imposed on the poles by dead-ending conductors; by changing conductor size, types, and tensions; or by angles in the transmission or distribution line. The guy should be considered as counteracting the horizontal component of the force with the pole or supporting structure as a strut resisting the vertical component of the forces. DOWN GUY.- A "down guy" consists of a wire running from the attachment near the top of the pole to
Figure 4-3.- Dead-end guy. the rod and anchor installed in the ground (fig. 4-2). This type of guy is preferable if field conditions permit its installation since it transfers the unbalanced force on a pole or structure to the earth without intermediate supports. A down guy used at the ends of pole lines to counterbalance the pull of the line conductors is called a "terminal guy" or a "dead-end guy" (fig. 4-3). All corners in the line are considered as dead ends. They should be guyed the same as terminal poles, except that there will be two guys, one for the pull of the conductor in each direction (fig. 4-4).
|
|