Design of Telecom Towers and Antenna Masts

Source data for design

Polygonal antenna poles, towers and masts for cellular communications and their foundations are designed on the basis of, and taking into account:

• results of engineering-geological surveys for the construction;
• the seismicity of the construction area;
• data on the purpose, structural and technological features of the antenna poles and foundations and the conditions of their operation;
• the loads acting on the antenna poles and foundations;
• the conditions of existing buildings and the effect of new construction on them;
• environmental requirements;
• the size of the plot for the antenna pole or mast;
• a technical and economic comparison of possible design solutions, to choose the one that makes the most efficient use of the antenna pole or tower and the foundations.

Structural features of antenna structures

The minimum wall thickness of steel polygonal poles for cellular communications is at least 5 mm. The bottom diameter of the shaft (the flange diameter) is chosen to suit the expected type and dimensions of the foundation.

Depending on the height required, the shaft can consist of one, two or more sections. The maximum length of a section (the length of a shipping element) is usually no more than 12 m, which is convenient for transport.

Sections are joined in two ways: flanged and telescopic. By the type of section joint, antenna structures are divided into poles with telescopic joints and poles with flange joints.

Telescopic joint. The approximate length of the joint depends on the diameters of the sections being joined: it equals one and a half to two diameters (about 1.8 times the mean diameter of the sections). In design, the possible deviation of the shaft length due to the tolerance on the length of the telescopic joint during erection is taken into account; 10–12% of the joint length is allowed. Structures with telescopic joints may have parts to draw the sections together and give a tight fit; if there are none, the sections are drawn together with a winch, with the cable passed inside the mast. It is recommended to draw the sections together under increasing load, in steps that depend on the diameter of the sections, until the sections stop moving relative to each other.

Flange joint. In polygonal poles and towers, flange joints with the bolts placed on a circle or along the outline of a rectangle are used, both at the joints between sections and at the foundation. A flange joint between sections ensures that the height of the shaft obtained during erection matches the design value exactly.

For servicing the antennas and transmitting equipment, poles and masts can have ladders and rest platforms.

Design of foundations for telecom towers

We design foundations for communication towers and antenna masts. Structural and technological solutions for foundations are individual and depend on the specific soil conditions and the load from the specific pole. The most common solutions are:

• from single steel shell piles;
• from single bored piles;
• pile foundations of screw piles with a steel grillage;
• pile foundations of steel shell piles with a steel grillage;
• with a monolithic reinforced-concrete grillage on screw, driven or bored piles, or steel shell piles;
• monolithic.

Shell pile

Shell pile strengthened with two crossbars

Vibro-driven shell pile

Bored pile

Multi-pile bored foundation

Monolithic and steel grillage on screw piles

Loads and checks in tower design

The tower is designed for wind load (taking into account the wind region and height), ice, the weight of the structure and equipment, and antenna loads that depend on the number, area and height position of the antennas. The calculation checks the strength and stability of the elements, the joints of sections and flanges, and the deflection of the tower top: telecom equipment requires limited antenna sway.

Equipment, safety and access

• a technological platform for telecom equipment;
• rest platforms every 10 m with a lockable hatch;
• a caged ladder and an anti-vandal hatch at the start of the ladder;
• if required: lighting fittings, a lightning rod, earth wires, CCTV systems.

What is needed for design and ordering

Send the tower height, the list of antennas (number, size, weight, mounting height), the location and, if available, the geotechnical survey results. You can also fill in the technical specification form for a telecom tower. We prepare the design and foundation and calculate the price and lead time; if needed, installation is carried out by a licensed construction partner company.