Telecommunication Engineering

These are towers and Mast that are stabilized by tethered wires – Guyed towers and Mast are designed and installed in the manner illustrated in the figure .-It takes cognisance of the following specifications and recommended practices:

• Guyed masts may be in lattice, triangular or square, tapered or straight, as well as monopole structural forms.
• Guyed masts are supported and held in position by guy wires or ropes.
• Mast Guy Ropes are made from pre-stretched steel. For every mast, the specified minimum strength of the guy wire is the maximum tension likely to occur in the worst loading condition.
• Guy wires are not over tightened in the installation of guy towers in order to avoid excessive tension which may cause alignment problems, cable rupture and permanent wrapping of tower structural parts.
• All sections are straight square sections to eliminate potential problems associated with twisting or the need to shim the legs.
• Typical tower sections have brace configuration with horizontals (z, x or k) and pivot base sections. These tower-structures are wholly of steel, modular and hot-dip galvanized.
• Guyed towers have tube or solid legs with solid bracing which increases the tower rigidity to allow for the twist and sway.
• The design, based on the load calculations determines the working load and the break strength required of the guy wire and ultimately the choice of the size and grade of the wire.
• The choice of each guy earth screw anchor is dependent on its holding power in the soil, which is a function of its diameter and length to be used to compute the minimum number of guys required.
• As a general rule, guys is planted in three directions at 120 o apart from each other. The distance from the base of the tower to the guy anchor base is one quarter of the height of the tower.

Self-supporting towers are free-standing lattice structures -Thy use of self-supporting towers with tapered sections, and face width that vary according to height and load capacity.-Recommended when land availability is limited PROVIDED that it is technically feasible. They have the following features:

• The triangular or square structure
• Tube legs, angle legs, lattice legs or solid round legs
• Sections in steel angle steel or steel tubes
• Steel angle cross bracing.
• Tapered sections
• Face widths vary according to height and load capacity.
• Rest platforms provided every 20 meters of height
• Work platforms provided at all height where antennas are to be installed
• Fitted with climbing ladderStandard support forms for lattice structures are specified as follows:
  • Lattice Leg
  • Angle Leg
  • Tube Leg / Solid Round Leg

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