Reinforced concrete poles are the load-bearing element in the construction of power lines. They bear heavy loads mainly from environmental influences, so the use of a combination of concrete and metal is fully justified. There are different types of such supports, each of which has its own purpose. The installation technology is complicated by the fact that even in the simplest version, the reinforced concrete support has a large mass and requires the use of special equipment for installation.
Reinforced concrete support structure
The support is based on concrete reinforced with a metal frame. Depending on the purpose, different compositions of solutions can be used. For example, maintenance of power lines from 35 to 110 kV is carried out using supports made of centrifuged concrete mixtures. The advantages that the design of reinforced concrete supports have include resistance to corrosion processes, as well as to the effects of chemicals and elements that are contained in the air. Such supports also have disadvantages. First of all, this is a significant mass, which complicates both the working operations for their installation and transportation. The material also hasrelative sensitivity to mechanical stress. For example, during transportation, supports are often damaged - cracks and chips occur on their surface.
Reinforced concrete pole rigging
Reinforced concrete supports can be provided with a metal frame formed by reinforcing steel. Thanks to it, the design acquires high reliability and protection from external influences. Also, the fittings are designed for installing wires on hooks or traverses. In the first version, supports are used, in which the corresponding holes were made at the factory for the introduction of hooks. It is important to note that the supply of functional components can be carried out before the installation of reinforced concrete supports at the work site. This feature distinguishes such structures from wooden ones, the equipment of which can only be carried out after installation.
Classification by installation method
There are different approaches to the installation of reinforced concrete supports. In this case, we are talking about methods of fixing in the ground - with installation on the foundation and with direct immersion in the ground. The supports that are attached to the foundation are also of two types: narrow base and classic. The first type is a structure that is installed on steel or reinforced concrete piles. The second option involves immersion in the ground, followed by pouring concrete. Such a reinforced concrete support is also called a frame or frame. It is used asfoundation structural element. Poles that are directly anchored into the ground are commonly used as a supporting structure for lighting systems, electrical wiring lines, etc.
Classification by purpose
In essence, the simple and reliable design has led to a wide range of applications for such elements. To date, the following types of reinforced concrete supports can be distinguished, based on their purpose:
- Angular. They are used at corners in the turns of the route of overhead lines (VL). Depending on the angle of rotation, other types of supports can be used for this purpose.
- Intermediate. Serve straight sections of overhead lines. These models are designed to support ropes and cables, but should not be used if additional loads are expected.
- Anchor. They are also used on straight sections of overhead lines, but they have one feature. With the help of anchor supports, transition zones are formed through natural barriers, engineering structures and other structures.
- Terminals. Air lines begin and end with these supports.
- A special reinforced concrete support is also common, which serves to change the configuration in the wires, and also provides support in difficult areas with branches, transitions and intersections.
Features of Power Line Poles
Reinforced concrete poles are the optimal solution for supporting overhead power lines. Metal and wooden counterparts alsoused for this purpose, but have a number of serious limitations. However, the reinforced concrete supports also have divisions according to the loads on the networks with which they can work. In particular, there are supports for lines from 10 to 1150 kV. In such a wide range, designs with different parameters are presented. The higher the voltage, the greater the mass and length of the traverse is the reinforced concrete support included in the network. It would seem that if the lines are at an approximately equal distance from the ground and the physical load on the structure is the same, then what caused the need to change the characteristics of the support? In fact, this is fully justified by technological requirements, which prescribe different standards for distances from the line to the support and the ground surface, depending on the voltage.
Installation technology
Work activities are started only after the completion of the site preparation and the delivery of components for installation. Further, the materials are laid out, an analysis is carried out, a plan is drawn up and grounding is carried out. After that, the assembly of the structure and its elements begins. Direct installation of reinforced concrete supports is carried out by special machines: installation cranes or boom equipment. Pulling up the racks can also be done with a tractor. A pit is also being prepared, the diameter of which may exceed that of the rack by no more than 25%.
If it is planned to install portal or two-rack supports, then the installation is carried out sequentially: first one, and then the second rack. This is followed by the installation of traverses, endingsinterstitial cruciate ligaments and fixation of their lower ends. When the lifting and installation of supports by special equipment is completed, the structures are temporarily unfastened with special braces, after which the crossbars are installed. You can proceed to the final stage in the installation of supports with backfilling of soil after the alignment of the position of the structure has been carried out.
