The choice of a reinforced concrete structure is almost always justified. It is only worth considering that reinforced concrete lighting poles are influenced by external factors:
- temperature fluctuations;
- atmospheric phenomena.
The choice of structural type of reinforced concrete supports
The design feature of the supporting devices must take into account the operational conditions of the area. It should also be understood that lighting installations must ensure the safety of movement along the streets. Reinforced concrete lighting fixtures can be used in both urban and suburban environments. The installation of lighting poles is considered suitable for main roads, pedestrian streets, industrial areas. Warehouse complexes are illuminated with the help of the system, etc.
Reinforced concrete poles are suitable for overhead lines with voltages up to 10 kV. The form of reinforced concrete structures can be very different. Reinforced concrete lighting poles belong to a complex structural type. Device brands suggest that the design of the OGK can be:
- octagonal;
- annular;
- round conical;
- faceted conical;
- trapezoidal.
Installation of OGK requires a certain sequence of work.
If the project, agreed with the local management, includes the installation of reinforced concrete options, it is not allowed to change the characteristics of the equipment in any case. In addition, the installation rules are initially provided for in the documentation.
The main installation methods involve the use of a reinforced concrete foundation. The devices are fastened with flange mounts or special studs to a metal mortgage located directly in the foundation. Devices of upright type are fixed in an earthen pit, into which a reinforced concrete mixture is also poured.
Sometimes the sequence of work involves drilling wells. Their depth should be 1.2 m, with a margin in width. The concrete mixture is poured into this free space. This composition is carefully compacted using special construction tools. It is planned to prepare a trench for the well, grounding the supports. The power cable is placed in it.
The choice of mounting method for reinforced concrete supports
The choice of mounting method for lighting poles is purely individual. Projects usually take into account factors such as:
- relief of the territory;
- the desired degree of illumination;
- power capacity;
- the number of devices involved;
- method of installation of load-bearing components;
- possibilities of local electrical networks.
Installation of lighting racks made of reinforced concrete OGK implies an obligatory stage of project preparation. Approval of the project requires compliance with certain rules. The established order includes:
- drawing markings in the conditions of the area where the work is implied;
- subsequent digging of holes, the standard dimensions of which are 1x1 m wide, 1.2 m deep;
- deepening the pit - implies the creation of a meter hole;
- fixing the support post, followed by adding crushed stone, as well as its tamping.
For greater reliability of the base, it is customary to strengthen the bottom of the pit with a cement mortar. In this case, the lamps should be installed only after the completion of the work on the arrangement of the pillars. Then the lamps are screwed into the lamps.
The established standardization rules make it possible to use both reinforced concrete and metal supports. The reinforced concrete structure includes reinforcement, which takes on tensile loads. At the same time, concrete has the ability to compress. Introductory shields are also part of the equipment. They provide electricity. Many parameters of this type of supports meet high quality standards. Particularly high strength for pillars of the main type. The cost of reinforced concrete products is lower than the price of metal supports.
In order for the lighting system to turn out to be really effective as a result of the work, it is necessary to correctly determine the distance between the lighting poles. This calculation necessarily includes the power value of the lighting devices themselves, their number, as well as the height of the supports. From the support to the curb, certain parameters must also be observed. Folding type cobras are sometimes used to achieve some effects. This information is largely interconnected with the type of illuminated object.
Reinforced concrete supports require periodic inspection of the condition. For example, metal structural elements should not contain corrosion. The condition of the support itself excludes the appearance of cracks. Bolted connections and anchor bolts mean trouble-free operation for several years. Introductory electrical panels are serviced by the services of local RES.
The area adjacent to the building should be well lit. Moreover, the lighting system must be organized in such a way as to cover as large an area as possible. For this purpose, street lighting poles are used.
These designs are usually subdivided, first of all, according to the material from which they are made. Metal supports are the best. However, structures made of other materials also have some advantages and are still widely used in lighting arrangements.
Classification
Supports are usually classified according to a number of criteria. In particular, according to the method of inputting current-carrying cables, the poles are divided into power and non-power. The former are used in the organization of overhead lines, the latter - underground.
Power structures are used where underground wiring is impossible for some reason. The interior of the structure includes a power cable. The height of the location of air networks is determined by the Building Regulations and Rules (SNiP).
For installation use brackets for fixtures. In addition to brackets, plinths are an integral part of the supports, which perform protective (protect the cable from damage and environmental influences) and aesthetic functions.
Non-power bearings are designed for underground laying of cables. The maximum permitted height for this kind of poles is 12 m. The cable should be buried in the ground by at least 80 cm. If we are talking about laying under the highway, the laying depth is set to 125 cm.
Note! Non-power poles are not used for the installation of high-voltage lines.
According to the method of installation, the supports are divided into straight-rack and flanged. The installation of the latter begins with the placement of the embedded element in the ground and its further concreting. When the mortgage is installed, the ground part of the structure is fixed to it with the help of anchor fasteners.
Upright supports are an integral structure, the installation of which is carried out in a pre-prepared niche in the ground. The hole is then filled with concrete.
Note! The ratio of the column dug into the ground and the outer parts of the column is determined by the manufacturer. This information is reported in the marking of the column.
The following types of supports are distinguished by shape:
- conical faceted;
- conical round;
- tubular cylindrical;
- tubular folding.
Purpose
According to the areas of application, the supports are divided into the following varieties:
- High mast. They are used for outdoor lighting of very large areas (for example, stadiums, airports, ski slopes). High-mast structures are offered in a variety of designs, differing in size, types of crowns, number of sections, surface type (faceted, smooth).
- Street structures for lighting pedestrian paths.
- Decorative supports. Used to illuminate local areas in gardens, parks, playgrounds, etc. Decorative poles are always non-powerful in their execution. Can be made with faceted or rounded surfaces. Luminaires can also vary significantly in their appearance and design, so the GOST applied to them will also differ. The installation height of decorative systems usually ranges between 2 and 4 m.
- Main supports. The main quality of such pillars is high resistance to mechanical and wind loads.
- Special supports. Used to illuminate individual objects (for example, squares). Structures of this type were used immediately after the advent of electrical networks. They are most often made from pine due to its optimal performance and low cost.
Types of supports
Supports are made of various materials: metal, wood, concrete, reinforced concrete. In recent years, products from composites have become widespread.
Metal supports
For the manufacture of supports of this type, steel, cast iron, aluminum and galvanization are used. Galvanized poles are especially popular, since they are characterized by high resistance to the negative effects of environmental factors.
Metal supports have the following positive characteristics:
- Light weight and dimensions. The lightest poles weigh about 150 kg, and flange structures (without mortgages) - about 40 kg. Due to the compactness, the transportation of poles is facilitated: 40 or more sets can be delivered to the site in one trip.
- High strength properties. For manufacturing, sheet metal with a thickness of 3 to 15 mm is used. This is enough to resist serious mechanical loads.
- No hassle with design changes. To increase or reduce the height of the support, you do not need to abandon the existing structure, you can simply increase it.
- Quick assembly and disassembly. To install the structure, it is enough to organize a hole of the desired diameter, into which to put the support, and pour it with concrete. For flanged racks, you first need to set the foundation tab and bolt the column to it.
- Long service life. Outdoor lighting poles are treated with a zinc coating that has anti-corrosion characteristics. The thickness of such a layer is 80 microns or more - depending on the needs. Service life of a covering - from 50 to 80 years.
- Attractive appearance. Regardless of the purpose, whether it is a decorative pole or a mast pole, the supports do not cause rejection by their appearance.
There are metal poles and disadvantages:
- The structure must be periodically painted, otherwise there is a high probability of rusting of the material.
- The cost of metal poles is higher compared to competing systems.
wooden supports
The advantages of wooden poles include the following qualities:
- Light weight. Thanks to this feature, wooden structures are easy to transport and install, which significantly affects the total cost of the lighting system.
- Easy to install. Often, for the installation of wooden poles, there is no need to use specialized equipment.
- Affordable material cost.
- Moisture resistance. Long service life. However, these qualities are achievable only when the material is impregnated with a special protective composition.
- Insulating qualities to prevent electrical shock.
The disadvantages of wooden structures include the following properties:
- Difficulties with the choice of logs of equivalent dimensions.
- Possibility of destruction of supports during heavy icing.
- Tendency to decay of untreated material.
Concrete supports
They are among the most common in the post-Soviet space. Especially often used in the 70-80s.
Among the advantages of concrete pillars, the following qualities should be distinguished:
- low cost;
- long service life (up to half a century);
- ease of maintenance (maintenance of networks is inexpensive).
Concrete structures also have disadvantages:
- instability to moisture (we are talking primarily about groundwater);
- unattractive appearance.
Note! The quality of concrete pillars is determined by the brand of concrete and the method of manufacturing the product.
Reinforced concrete supports
Reinforced concrete pillars are a frame metal structure covered with concrete.
The advantages of reinforced concrete supports include the following characteristics:
- ability to withstand heavy loads;
- durability;
- acceptable cost;
- resistance to temperature changes, which allows the use of poles in areas with a cold climate;
- corrosion resistance.
Reinforced concrete products also have disadvantages:
- an unattractive appearance repels buyers seeking a decorative effect from the lighting system;
- poor impact resistance.
They produce reinforced concrete products with rounded and faceted surfaces. In recent years, reinforced concrete products have been actively replaced by supports made of more functional materials.
Support dimensions
The height, width and weight of products are determined by the material from which they are made. An example is the following data:
- Wooden poles are produced in five versions: 6.5 m, 7.5 m, 9.5 m and 11 m. The diameter of the poles varies between 14 and 24 cm. By weight, wooden poles are divided into three groups: light, medium and heavy.
- Concrete poles are heavy. Depending on the size, the product can weigh from 300 kg to a ton. The width of the column is from 10 to 40 cm. The height of the structure is within 4-11 m.
- Reinforced concrete poles are offered in the same dimensions as concrete poles. However, reinforced concrete products weigh much more, since they have a metal component. The weight of the standard design can be within 450-1200 kg.
- For metal products, a minimum height of 1.5 m is adopted (in the case of floor lamps). The thickness, diameter and mass of the lighting system are determined by its tasks and configuration.
The number of sections in a metal lighting mast depends on its height. The three-section mast has a height of 21 meters. Masts with four sections have a height of 28 m, five sections - 35 m, 6 sections - 45 m.
Installation rules
Before installing the supports, it is necessary to develop a project taking into account the following circumstances:
- relief of the site;
- the desired level of illumination;
- power consumption;
- control and protection system;
- number of light sources;
- method of installation of load-bearing elements and electrical equipment;
- the ability to connect to the power grid.
During installation work, you must adhere to some rules that directly affect the safety of the system and its service life:
- to perform electrical installation, all necessary permits from regulatory authorities must be obtained;
- the installation of flanged columns is started only after the final solidification of the concrete (you will have to wait 4-5 days - depending on the humidity and temperature of the air, the brand of concrete);
- in order for the flange fastening to be reliable, it is advisable to use castellated nuts with a cotter pin;
- metal poles are recommended to be treated with a protective primer and paintwork material;
- if the installation is carried out in soft soil, it will be necessary to create a pillow consisting of a sand-gravel mass.
The installation of metal support structures - regardless of their variety - differs only in the amount of work and small details. In general, the technological process is very similar.
Preparatory work
Before starting work, prepare a trench for laying the power cable. The recess should have a square section, where the side will be equal to 1 m. The depth of the pit is 80 cm or more (depending on the type of pole being installed).
The bottom of the pit is covered with a layer of sand mixed with rubble. If only sand is used, it is moistened with water. Such a base is easier to tamp.
Power cable laying
The next step is to connect the power cable to the lighting fixture. This is done underground or above ground. Most often, the cable is brought underground. A layer of pure sand is poured under it. A signal tape is laid on top. Its presence will prevent accidental damage to the line and electric shock.
Mounting brackets
There is a special hole in the bottom of the support. A power cable is brought through it, then pulling it up. When this operation is completed, brackets for lamps are fixed at the top of the support. The number of horns on the bracket is selected in advance - before installation. Next, the fixtures are connected and light bulbs are mounted in them.
Installation of metal supports
A column is installed in the well, centered, aligned vertically and fixed with temporary struts. The correctness of the installation is checked using the building level. Fill the voids in the well with concrete. When it is completely dry, remove the supports. Support structure for street lighting installed.
However, before putting the support into operation, it is necessary to carry out a number of works, including checking the integrity of the cable. It is also necessary to create a ground. Without it, the system cannot be considered safe to operate.
To organize the grounding, you will need a grounding cable. One end is attached to a bolt (located at the bottom of the pole), where the power cable is inserted. The second end is fixed to the ground loop.
Note! The resistance of the ground loop must be at least 40 ohms.
Two types of grounding systems are most in demand today:
- Three-phase networks with tightly grounded neutrals. TN-S provide high quality protection against electric shock. Such systems are mounted near schools and crowded streets.
- For street lighting it is recommended to use insulated conductors with four wires with a cross section of 25 mm. Inside the cable is a galvanized steel tape that acts as a grounding device.
The poles are installed in such a way that they are located on not too damp areas of the earth. The distance between the supports is chosen so that the lighting fixtures fully illuminate all the necessary areas. At the same time, the lamps should not give powerful streams of light into the windows of nearby buildings. Overlapping of light fluxes from different lamps should be avoided. Firstly, this is a waste of electricity, and secondly, in such areas the lighting will be too bright.
Installation of flange supports
After installing the embedded blocks (flanged supports), they are centered. This is done using reinforcement hammered into the walls of the trench. Next, concrete is poured into the holes, compacted with a vibrator. A rack is attached to the mortgages with bolts. The installation is completed by fastening the sip cable to the sfg (power faceted flange).
Installation cost
To calculate the cost of pillars, you need to have information about their size and type of structural material. Prices for wood supports vary between 2-7 thousand rubles. Concrete structures cost from 4 to 13 thousand rubles, reinforced concrete products - from 5 to 15 thousand rubles. Metal supports are the most expensive - up to 20 thousand rubles.
The costs do not end there, as the supports still need to be installed. The cost of screeding, drilling wells and installation can be in the region of 3-4 thousand rubles per pole. You also need to purchase a street lamp, the cost of which can range from several hundred to thousands of rubles.
Reinforced concrete power transmission towers are made of concrete, which is additionally reinforced with metal, as the name implies. They are labeled CB, which means "vibrated racks". They are used for laying power lines 0.4-10 kV.
Significant advantages of reinforced concrete supports are:
- Corrosion resistance
- Immunity to low temperatures and humidity
- Seismic resistance - the degree of resistance to earthquakes
- Resistance to the adverse effects of nature and the elements
- Increased strength and strength - not subject to deformation and destruction
- No need for maintenance (what, for example, pine wooden poles need - impregnation)
- Service life - at least 50 years
There are disadvantages too
We are talking here, first of all, about the high weight of such a support, respectively, the installation of supports of this type should be carried out by professionals of the highest class. There is also a possibility of various defects during transportation (we are talking about cracks, chips). In addition, due to exposure to moisture and temperature fluctuations, chipping of concrete is possible, which reduces the strength of the entire structure.
Characteristics of reinforced concrete racks of power lines
⇒Reinforced concrete poles are made of different brands and are designated in this way, for example, a concrete pole SV 95-2, where 95 is the length of the pole in decimeters, and 2 is the conditional bearing capacity.
According to GOST 23009-78 racks are manufactured in the following sizes:
- L - 9.5 meters (CB 95)
- L - 10.5 meters (CB 105)
- L - 11 meters (CB 110)
- L - 16.4 meters (CB 164)
They also differ in the method of reinforcement, on which the bearing capacity depends.
Racks of supports of power transmission lines SV 95
Reinforced concrete supports SV 95 are widely used for laying and installation of networks with a voltage of 0.4 kV and for laying communication lines. They are mainly used for, when installing an additional electric pole. For their manufacture, heavy concrete (class B30) is used, which complies with the standards of GOST 26633-91. As a filler for this concrete, manufacturers use crushed granite with a strength index of at least M 1200 - M 1400, frost resistance F 300.
Racks CB 95 can be operated at temperatures reaching -55 degrees Celsius. They are successfully operated in areas of category I-V and can be installed where seismicity does not exceed 7 points on the Richter scale. Reinforced concrete poles of power transmission lines SV 95.2 and SV 95.3 are equipped with embedded products necessary in order to fasten structures and connect the necessary grounding elements. These racks taper upward and are 9.5 meters long. The cross section of the supports is rectangular and equals: at the base, the height is 240 mm, at the top - 165 mm, the width at the base and at the top is the same - 150 mm. The rack weight is 750 kg.
The reinforced concrete pole SV-95 at the manufacturer is supplied with embedded iron products intended for attaching structures and grounding parts.
Racks CB 110
Reinforced concrete racks SV 110 are designed for power lines with voltage up to 10 kV. They can also be installed for communication lines. Reinforced concrete poles SV 110 are resistant to aggressive environments, low and high temperatures and can be successfully installed in areas with a high degree of fire danger.
Reinforced concrete pillars SV 110 also find their application in quality. Their production is carried out using heavy concrete by vibrocompression. These concrete mixtures have a compressive strength class of B30.
The length of the racks CB 110-3.5 and CB 110-5 is 11 meters. At the base of the support, the height is 280 mm, and at the top, the height is 165 mm. The width of the base is 170 mm, the upper part is 175 mm. The weight of the concrete support is 1150 kg. Racks CB 110-3.5 have a calculated bending moment of 35 kNm, and CB 110-5, respectively, 50 kNm.
Reinforced concrete supports SV 110 are made of heavy concrete with the following characteristics:
- Strength grade - M 400
- Frost resistance - F 200
- Water resistance - W 6
Each of them is equipped with embedded metal products intended for fixing structures and connecting parts of the grounding structure and is manufactured in strict accordance with GOST and TU standards.
All supports must have a certificate of conformity and a quality passport.
Concrete outdoor lighting poles are used in urban, suburban conditions. They are designed to illuminate highways, streets, sidewalks, industrial areas, and other objects. Such a street lighting system is also used as a backlight for power lines energized at 10kV. For power lines under voltage over 35 kV, such lighting poles are made from centrifuged concrete.
Reinforced concrete poles for lighting are manufactured in various sizes, shapes using vibrocompression and centrifugation technologies. High-quality concrete, metal reinforced wire are used as consumables.
In this article:
Characteristics of w / w illuminators
Reinforced concrete poles are used to illuminate urban, suburban roads, adjacent areas of industrial enterprises, warehouses, sports grounds, city parks, as well as private houses and suburban areas.
Advantages of lighting reinforced concrete poles
- Perfectly resist corrosion, rotting, chemical and mechanical influences.
- They have a fairly long service life. Subject to the requirements for production and installation, as well as proper transportation of structural elements, such illuminators can last more than 50 years.
- Minimum operating costs.
- Reinforced concrete structures are characterized by increased fire resistance.
- Products are not difficult to manufacture, perfectly amenable to repair.
- Maintenance of concrete reinforced lighting structures does not require significant financial costs.
Disadvantages of reinforced concrete structures for street lighting
- The complexity of loading / unloading, transportation and installation of reinforced concrete elements due to the rather large mass. For loading and unloading and installation work, it is necessary to use special equipment.
- The complexity of dismantling the structure, special equipment is also needed.
- Significant costs for the disposal or recycling of reinforced concrete supports.
- Concrete products are quite sensitive to changing weather conditions, sudden temperature changes.
- Lighting devices on reinforced concrete poles are prone to cracking, chipping, which cast doubt on the reliability of the product.
Varieties of concrete reinforced pillars for lighting
Reinforced concrete poles are divided into the following types:
- corner;
- intermediate;
- terminal;
- anchor.
For industrial use, concrete racks are reinforced in two ways:
- frame;
- tension.
Products differ from each other in reinforcement technology, weight, overall dimensions, respectively, have different markings.
Different designs of reinforced concrete lighting racks differ from each other in the following operational properties:
- resistance to wind, ice loads;
- frost resistance level;
- temperature mode of operation;
- concrete density;
- the level of moisture absorption;
- electrical voltage drop.
Production technology
The process of manufacturing outdoor lighting fixtures on reinforced concrete racks is divided into several stages:
- reinforcement preparation;
- preparation of concrete mortar;
- preparation of forms;
- pouring concrete mixture into molds;
- drying the finished support.
Armature preparation
At this stage, a selection of fittings of the required type and size is made. It is cut, for which special equipment is used, and contour spirals are screwed in.
Preparing a mortar from concrete
For the production of a concrete mixture, cement of a certain brand, mineral and chemical additives are taken. All components are placed in a concrete mixer, water is poured in the prescribed proportion, the mixture is mixed until a homogeneous mass.
Preparing molds and cores
For the manufacture of directly reinforced concrete racks for lighting equipment, special forms are used, which are thoroughly cleaned and lubricated before pouring the concrete mix. First, metal spirals are placed in molds, then a rod is made. The steel rod is preheated, then pulled through the spiral, fixed in the container.
Pouring concrete mixture into molds
When the fittings are placed in the container, the prepared solution is poured. A special vibrator is used to compact it in the mold. The surface is leveled with an ordinary construction trowel.
Drying the finished support
After completing all the main stages of production, the product is dried. The concrete product in the form is covered with a PVC film (to prevent moisture from entering the structure), heating is turned on. After a set time period, the plastic film is removed.
Mounting racks
Installation work begins with the preparation of a project, previously agreed with the authorities.
Installation procedure:
- on the ground where reinforced concrete supports for illuminators will be installed, markings are applied;
- pits are prepared with the following parameters: depth - 1.2 m, width - 1x1 m;
- a hole is made in the center of the pit 1 m deep;
- the concrete reinforced support is fixed in the pit with crushed stone, which is carefully compacted as it is backfilled.
Note! In certain situations, the bottom of the pit is additionally filled with concrete mortar. Such a basis is more reliable. After the installation is completed, lighting equipment is mounted on the racks, the lamps are screwed in.
Grounding of reinforced concrete racks
Grounding devices are installed on reinforced concrete racks intended for power lines with voltage up to 1 kV. They are necessary for diverting lightning surges to the ground. The lighting equipment itself is similarly grounded. Housings of lighting devices are connected to the ground loop.
The ground loop is made of steel pins (diameter from 6 mm), corners. They are installed in a triangle, interconnected by a strip of metal. The grounding device must have a resistance of up to 30 ohms.
Service
Reinforced concrete structures must be subjected to periodic maintenance:
- corrosion is removed on the metal parts of the structure - once every 3 years;
- cracks in concrete are smeared - once every 6 years;
- the reliability of bolted connections is checked once every 2 years, if necessary, they are tightened.
Conclusion
Concrete lighting poles are complex structures that require compliance with building standards during their installation and certain periodic maintenance. Thanks to such lighting structures, the safe movement of vehicles on highways, pedestrians, as well as the performance of various works at night is ensured.
