Reinforced concrete (RC) transmission line supports and poles: main types, installation, assembly

Transmission line supports and poles made of reinforced concrete (RC) are vital components of the infrastructure that powers our cities. These buildings are made to safely support the weight of high-voltage power lines while withstanding the weather. The preferred material is reinforced concrete because of its strength and endurance as well as its resistance to weathering and corrosion over time.

RC transmission line supports and poles come in various primary varieties, each with a distinct function based on the terrain and the voltage of the power lines they support. Common varieties include lattice towers, which are used for higher voltage lines and require more complicated assembly, and single pole structures, which are usually used for lower voltage lines and easier to install.

Implementing RC transmission line supports and poles necessitates meticulous preparation and implementation. The first step is site preparation, in which each structure’s ideal location is determined by assessing the terrain. After that, foundations are built to firmly fasten the poles to the earth, guaranteeing their stability and ability to support weight. The poles are assembled at the installation site using cranes and other specialized machinery after being manufactured off-site and transported there.

These structures need to be assembled with expert labor and careful attention to safety procedures. To properly support the power lines, parts like conductor fittings, insulators, and crossarms are firmly fastened to the poles. In order to guarantee the dependability and security of the transmission lines, the assembly procedure needs to take into account elements like wind loading and electrical clearance specifications.

All things considered, RC transmission line supports and poles are an essential component of our infrastructure that allow power to be transmitted over long distances in an effective and dependable manner. To meet the requirements of contemporary electrical grids, their design, installation, and assembly call for skill and meticulous planning. The development of new building materials and techniques keeps pace with technological advancements, guaranteeing that these structures will always adapt to the changing demands of our communities.

Classification by purpose

The electric support RC products are designed to be able to support a significant portion of the load from stretched straight wires along with their branches, bends, and turns.

A number of support structure types are distinguished by purpose in the PUE and GOST standards for implementing the necessary parameters for tensioning and holding overhead line wires:

• special;
• terminal;
• angular;
• anchor;
• intermediate.

Special

They consist of the following varieties:

1. For the purpose of passing natural or artificial obstacles – transitional.
2. Anti-wind – used in areas with strong winds.
3. For the implementation of intersections of overhead lines from different sides – crossover.
4. Transpositional – used to change the position of wires.
5. To connect new subscribers, branch structures are installed.

Terminal

They fall under the category of anchor systems, albeit with a unique one-way tension design. The letter "K" is used to identify them.

Angular

Utilized where overhead power lines veer. Standard abbreviation: "U". Anchor-type products are installed at large angles and intermediate at small angles. In the center of the turning angle is where the total load from two adjacent spans is greatest.

Anchor

Wire tensioning is done on straight sections when installing overhead power lines with anchor systems.

Additionally, supports are erected when a line crosses a river, a road, an obstacle, or a branch of a railroad.

Intermediate

The purpose of these structures is to support the wires, not to tension them. But they are still made with a safety margin in case of accidents.

Intermediate structures are installed between anchor structures without bends and turns. 85% of supports in an overhead line are intermediate.

Marking of concrete supports

Products made of reinforced concrete are marked with a combination of numbers and letters.

The initial letters of the support indicate its purpose:

1. Anchor branch – OA.
2. Anchor corner branch – UOA.
3. Anchor ends – AK.
4. Transitional corner anchor – PUA.
5. POA – transitional anchor branch.
6. PP – transitional intermediate.
7. O – branch.
8. Angular intermediate – UP.
9. Intermediate – P.

The line for which the design is intended is characterized by the first digit. This is a 35–35 kV power line, for instance.

The size is the next number. "1" denotes the assumption that the support is 10.5 meters tall and is built using the SV-105 pillar as a foundation. It will be "2" if pillar 110 is utilized.

SV stands for "vibrating" racks, which are used to make concrete supports. Next, add the length in decimeters, the bending moment, and the conditional load-bearing capacity (SV 164-2-2, for example).

Roman numerals (III, IV – reinforcement class) and letters (a, b, s, av, ag – variations in the manufacturing process) can also be used to designate pillars, as in the case of SV 95-3s-IV.

Constructions

The foundation of the power line support is a concrete-filled, reinforcing metal frame.

Depending on the structure’s intended use, the solution’s composition changes. Concrete mixtures centrifuged are used to make products for power transmission lines ranging from 35 to 110kV.

• large weight, which makes their transportation and installation difficult;
• chips and cracks, which may appear due to unforeseen mechanical impacts (shaking, impacts).

1. Communication and sectional devices.
2. Cable end couplings.
3. Protection devices.
4. Panels and cabinets for electrical receivers.
5. All types of outdoor lighting fixtures.

In addition to the material (fiberglass, wood, metal, or reinforced concrete), power transmission line products vary:

• number of circuits;
• line voltage;
• terrain conditions on which the route is located (soft soils, marshy areas, mountainous conditions, presence or absence of population).

Elements of the support system

Reinforced concrete pillars (posts) are the primary components of the majority of concrete lighting, transition, transposition, etc.d. support structures. It gives the wires’ necessary dimensions. Three or more of them are possible in a single support.

1. Braid (takes part of the load of the wire tension on one side).
2. Additional part – the lower part, which is dug deep into the ground.
3. Diagonal – a part connecting a number of elements, increasing the rigidity and rigidity of the entire system.
4. Crossbar for securing wires.
5. Foundation – serves to transfer loads from external influences (wind, ice), wires, insulators, posts to the ground. A single-post reinforced concrete pillar does not need monolithic, pile or prefabricated foundations. The lower ends of such elements are simply sealed into the ground.
6. Beam – increases the ability of the foundation to hold loads in a horizontal plane. Increases the stability of the supporting structure, prevents overturning on weak soil from the action of the gravitational forces of the line.
7. Additional elements: cable supports, guy wires, extensions, footrests.

Concrete supports by the number of chains they hold

The different categories of supports are based on the quantity of chains.

Poles and supports made of reinforced concrete (RC) are essential components when building transmission lines. These structures range from straightforward poles to intricate lattice towers, each designed to meet a particular purpose. Prefabricated component assembly, foundation preparation, and careful planning are usually needed when installing RC transmission line supports. Safety regulations must also be followed. It is important to comprehend the assembly process, which includes steps like installing electrical fittings, pouring concrete, and positioning reinforcement bars. This article examines the various RC support types, explains how to install them, and identifies important factors to keep in mind when building a transmission line infrastructure that is dependable and long-lasting.

Installation

GOSTs and SNiPs set the guidelines for installing reinforced concrete supports, and Moscow and other Russian regions follow the same rules.

The support is assembled on a level area cleared of foreign objects. For heavy structures of 35 kV and more, riggers are involved.

Process maps that list the necessary equipment, the order of operations, and the part layout (beams, crossbars, racks) are typically used during installation.

Procedure for assembling vibrated rack single-column supports for power transmission lines up to 10 kV:

1. In order to secure the crossbar and grounding descent, the top of the product is raised. The braces and traverses are put on the bolts, the nuts are installed and tightened.
2. Before installing the insulators, fill the polyethylene caps. Insulators are mounted, nuts are punched.
3. At the end, a poster-stencil is installed, where the year of installation, serial number is indicated.

The extension method, a crane, or a helicopter are used to raise the supports. The accuracy of the pit and foundation preparation is verified prior to installation.

Different types and sizes of supports are used for different lines.

Overhead lines up to 1 kV

Installed on overhead lines with a voltage of less than 1 kV are the following supports:

• single-column free-standing unified intermediate;
• A-shaped end, anchor, corner;
• single-column with braces;
• prefabricated from vertical posts installed next to each other.

It is feasible to assemble and install reinforced concrete supports from vibrated posts that are designed to hang two to nine overhead line wires and four to four radio wires.

Steel crossbars are used in such structures. In addition, they serve as supports for lighting, supporting cable sleeves, branch brackets, and lamps.

VL up to 10 kV

Single-column products with braces and intermediate, anchor, end, and corner – A-shaped connections are installed for overhead lines between 6 and 10 kV.

Vibrating pole SNV structures feature a crossbar that can support three aluminum wires up to 120 mm² in length.

Steel crossbars are installed on anchor and corner single-column supports with braces to accommodate wires for every phase.

Apical pins and wood crossbars measuring 80 by 100 mm are installed on intermediate single-column supports composed of centrifuged poles.

VL 35-500 kV

Portal and single-column free-standing unified supports with guy wires are utilized on lines with voltages greater than 35 kV.

Their asphalt-bitumen waterproofed poles, crossbars, and cable supports are their structural components.

Plug covers are installed on the bottom of the rack to keep moisture out and provide additional support area and strength to the structure embedded in the ground.

The top portion of the post has holes where traverses can be fastened. The concrete contains the grounding slope.

Rollers, clamps, and unique brackets inserted into the openings in the cable stands and traverses are used to secure the coupling fittings (brackets and earrings). Clamps are used to secure the metal cable supports to the poles.

On 330–500 kV power lines, single-column portal supports with metal traverses are installed as an intermediary.

Intermediate structures with conical and cylindrical posts, as well as 2- or 1-circuit free-standing single posts, are utilized for 35-220 kV lines.

For overhead lines rated 35–110 kV, anchor corner structures are manufactured as reinforced concrete products with guys.

Grounding

The factory production site is where structural grounding of all lighting poles and overhead line racks is done. Ten millimeter reinforcement is exposed at the top and bottom of the product. The steel rod supporting this reinforcement extends the full length of the column.

The zero wire is grounded (re -ground) following the grounding of the reinforcement. The conductor needs to be larger than 6 mm in diameter.

Less than 30 Ohms should be the resistance of the grounding device. If the soil resistance in a populated area is less than 100 Ohms/m, it can be as low as 10 Ohms.

The PEN conductor is connected to the reinforcing, support struts, phase wire hooks, and pincers for reinforced concrete structures. In the event of removals, they serve as ground conductors for reinforcement as well.

According to the project, the earter is mounted in reinforced concrete pillars:

1. The standard trench depth of 1 m with a width of 0.5 m.
2. Contours are formed and the elements are enveloped.
3. Corrosion joints are protected.
4. The grounding descent is mounted.

Grounding is accomplished through the shell of lighting supports that use power cables.

Type	Description
Single Pole	Simple, vertical structure used for low to medium voltage lines. Easy to install and maintain.
H-Frame	Two poles connected by a crossbar. Used for medium to high voltage lines. Provides stability and support for heavy loads.
Monopole	Single, large-diameter pole. Often used in urban areas where space is limited. Strong and durable but can be more expensive.
Direct-Buried	Pole is embedded directly into the ground without a concrete base. Simplifies installation but may need additional support in soft soils.
Embedded Footing	Pole is set into a concrete base buried underground. Offers high stability and load-bearing capacity, suitable for high voltage lines.
Installation	Typically involves setting poles into prepared holes, securing with concrete or anchors, and attaching hardware for lines.
Assembly	Includes erecting the poles, connecting crossbars, and installing insulators and conductors. Ensures alignment and safety.

An essential component of maintaining the stability and dependability of electrical infrastructure is the use of reinforced concrete (RC) transmission line supports and poles. These structures are available in a variety of forms, each intended to handle distinct loads and environmental circumstances. Every type of structure, be it a towering tower for high-voltage transmission lines or a basic pole for local distribution, is designed to fulfill a particular purpose.

The installation of RC transmission line supports requires careful preparation and handling. Engineers evaluate the topography, soil properties, and environmental aspects prior to starting construction in order to choose the best kind of support structure. Usually, the procedure begins with foundation preparation, which may entail digging, installing reinforcing steel bars (rebar), and pouring concrete. To guarantee longevity and durability, the assembly of these supports calls for specialized labor and adherence to safety procedures.

Exact techniques are used during the assembly of RC transmission line supports and poles to guarantee structural integrity. Precast sections or formwork are examples of components that are used to shape concrete in accordance with design specifications. Strategically positioned steel reinforcement improves strength and flexibility within the concrete formwork, which is essential for withstanding wind, seismic activity, and other stresses over time.

Overall, transmission line supports and poles made of reinforced concrete are an excellent example of how engineering precision and practicality can coexist. In addition to supporting the weight of power lines, they are made to endure environmental stresses and offer dependable service for many years. The efficiency and sustainability of these vital structures are continually being improved by new materials and construction techniques as technology develops, guaranteeing a reliable electrical grid for communities everywhere.

Video on the topic

Installation of the strut to the support (installation of anchor)

Installation of SV-105 support

Installation of power lines

Installation and assembly of power line support

Overhead power lines with a voltage of 6-10 kV. Installation of supports and installation of self-supporting insulated wires

Fall of a power transmission line support. Failed to hold.

Installation of power transmission line supports. Construction of 0.4 kV power lines.