Mushroom foundation for power line support. Mushroom-shaped foundation for houses in wet areas Product quality control

Unified reinforced concrete foundations are used when installing supports for power lines with a voltage of 35-500 kV. Widespread use of unified reinforced concrete foundations for securing power transmission line supports is due to the historically formed base of standard design solutions using such structures, the positive experience of their use, as well as the serial development of products by reinforced concrete factories.

Monolithic ones are used as reinforced concrete foundation structures for installing overhead line supports. mushroom-shaped footrests with vertical or inclined post, various composite foundations, piles from stressed and non-stressed reinforced concrete. To increase the bearing capacity of the foundation in soft soils, special support and backing slabs have been developed, crossbars. As a foundation structure for guy wires of overhead line supports, anchor plates. In single-circuit reinforced concrete and wooden supports of overhead lines up to 35 kV, in the supports of communication lines, reinforced concrete trapezoidal consoles.

Dear Clients! Our company offers you to buy reinforced concrete foundations and their components at the most fair prices. We will deliver structures using our own and hired transport to any region of the Russian Federation. When filling out the application, please indicate the exact labeling of the products and the delivery address.

Mushroom-shaped foundations for standardized metal supports of 35-500 kV power lines are produced serially in accordance with working drawings according to series 3.407-115. The project developed foundations of various overall dimensions and designs of the main parts. The main group includes monolithic mushroom-shaped footrests with inclined or vertical posts, footrests with hinged slabs, prefabricated foundations with a bolted connection between the post and the base plate. An additional group includes mushroom-shaped monolithic foundations for anchor-corner power transmission line supports with modernized caps equipped with pockets for bolts and elevated composite foundations with a welded or bolted connection between the post and the lower part. The use of prefabricated and composite foundations is due to the need to create large-sized foundations for special application conditions.

Unified composite foundations for steel power transmission line supports series 3.407.1-144

Unified prefabricated foundations series 3.407.1-144 were developed by the Energosetproekt Institute to replace their mushroom-shaped predecessors in series 3.407-115 issue 2, 3. The foundations are used as footrests for free-standing metal supports of 35-500 kV overhead lines. The design is convenient for transportation; it consists of separately manufactured reinforced concrete slabs and racks, which, at the site where the foundation is installed, are fastened together with two keys.

Replacement of foundations of the 3.407-115 series with foundations of the 3.407.1-144 series can be carried out according to the replacement table and on the basis of verification calculations of the bearing capacity of foundations for standardized power transmission line supports.

Foundations of metal supports for overhead lines project 13478tm

Foundations for steel intermediate and anchor-angular supports of 35-500 kV overhead lines according to standard design 13478tm are made in the form of monolithic footboards. The standard project 13478tm was developed by the Energosetproekt Institute as a modernization of foundation structures, taking into account technological improvements and production features at the Svetlogorsk ZZhBIiK JSC enterprise. Mushroom foundations produced in formworks of similar foundations of project 3.407.-115 issue 1 in accordance with TU 5800-001-00113371-2001.

The marking of foundations for standardized overhead line supports according to project 13478tm is identical to the marking of reinforced concrete structures of the 3.407-115 series. The index “c” added to the marking indicates the manufacturer.

Reinforced concrete foundation piles for overhead line supports series 3.407-115

Vibrated reinforced concrete piles for the construction of foundations for 35-500 kV overhead lines are produced according to standard design drawings 3.407-115 issue 4.
The piles are made in the form of solid driven reinforced concrete structures of square cross-section with a pointed tip and cap in accordance with the marking of the pile. The reinforcement frame of the piles is made of non-tensioned longitudinal reinforcement. The project provides for the production of 6 and 8 meter piles with transverse trunk dimensions of 25x25cm, and 8, 10, 12 meter piles with a cross section of 35x35cm.
Reinforced concrete piles used in single-pile and multi-pile foundations for overhead line supports, designed for operation in various climatic conditions, in various soils, including swampy ones. Exceptions are rocky soils and artificial fill soils with solid inclusions.

Reinforced concrete piles of square section are manufactured in accordance with working drawings series 3.407.9-146 issue 2, and are used in foundations for steel supports of 35-500 kV power lines.
4 standard sizes of piles with a square section of 35x35 cm, lengths of 6, 8, 10, 12 m with two types of reinforcement, with prestressed and non-prestressed reinforcement were developed - a total of 14 grades of piles. All pile heads are made with an embedded part in the form of a metal sheet with a long pin, which is cut off if necessary. In the foundation of the support rack with guy wires, support plates are welded to the sheet of the embedded part; in the foundation of free-standing steel supports - caps with two or four bolts are welded; To secure the guys, brackets are installed in the side hole of the pile. Project 3.407.9-146 issue 2 also provides for the production composite reinforced concrete piles for overhead line supports up to 24 m long.

Special reinforced concrete piles for the construction of foundations for overhead line supports in the regions of Western Siberia, they are developed and manufactured according to the drawings of the standard design 12614tm-t1.

The project developed 4 standard sizes of piles with a square section of 35x35 cm, lengths of 6, 8, 10, 12 m. The piles are made of ordinary vibrated reinforced concrete. Foundation piles under standardized overhead line supports are used in any ground conditions, including deep swamps. The decoding of the symbol for piles according to project 12614tm-t1 is similar to series 3.407-115 issue 4, with the exception of the marking of the head: Нр – head with one bolt for fastening the grillage or shoes of steel supports.

Reinforced concrete crossbars are produced in accordance with standard drawings of the 3.407-115 and 3.407.9-158 series and are used when installing 35-750 kV overhead line supports.

Crossbars serve to increase the lateral surface and load-bearing capacity of support foundations under the action of horizontal overturning loads from the traction forces of the wires. This is especially true when constructing power lines in soft soils.
Depending on the application reinforced concrete crossbars differ in overall dimensions and have different markings. The crossbar is fastened to centrifuged, vibrated reinforced concrete racks and unified footboards of metal overhead line supports using special clamps through the provided design holes.

Anchor, support and backing plates are standard designs for installing overhead line supports and are produced in accordance with drawings series 3.407-115 issue 5.

Anchor plate PA for fixing guy wires of steel or reinforced concrete supports of 35-500 kV power lines is made in the form of a monolithic reinforced concrete rectangular structure of 6 standard sizes with a longitudinal stiffener in the center.
Base plate The OP for supporting the reinforced concrete pole of the overhead line support in weak soils has a round or square shape in plan depending on the marking and is equipped with a cup for installation.
Backing plate PP is used in soft soils to expand the support area of ​​support foundations to dimensions of 3.6x3.6 m, and is manufactured in the form of a flat rectangular structure.

Reinforced concrete attachments are produced according to standard drawings of the 3.407-57/87 series in accordance with technical specifications in accordance with GOST 14295-75. Reinforced concrete attachments are based on heavy vibrating concrete. Reinforcement of products is carried out using welded or knitted spatial frames.
Reinforced concrete trapezoidal attachments PTs are used when installing single-circuit reinforced concrete or wooden overhead line supports with voltages up to 35 kV. In addition to the construction of power lines, PT set-top boxes are widely used in the installation of telephone and telegraph communication lines.
PT set-top boxes can be used in slightly aggressive environments, as well as in highly aggressive environments using waterproofing. The designs of the attachments are designed for operation in the IV and V icy and windy regions at air temperatures not lower than -55°C and seismicity up to 9 points.

Mushroom footrest foundation F 3-05 – is a monolithic reinforced concrete structure designed for installation of overhead power line supports with a voltage of 500 kV overhead power lines based on metal supports. A mushroom-shaped foundation F 3.05 with an inclined post is available. This rack has embedded parts that are used for fastening directly to the support. A mushroom-shaped foundation cannot be dispensed with if the power transmission line is supposed to be 6 meters or more in height. The mushroom footrest is used not only in guyed supports, but also in free-standing supports.

The foundation of a power line support in the form of a footrest is a structure with a pyramidal slab and a stand. This structure is laid to a depth of 1.5 to 2.5 meters. The bearing capacity of such foundations, based on the strength of the structure, is up to 770 kN. The foundation is called mushroom-shaped because of its shape, similar to an inverted mushroom. In this case, the “leg” or stand can be depending on the area of ​​application

can be vertical or inclined. The straight post in the head has an embedded part with a vertical pin. The purpose of such a foundation F 3-05 is to support vertical inclined pillars of supports with guy wires.

The mushroom-shaped foundation significantly increases the resistance of the power transmission line structure to wind loads. High-quality foundations made of heavy concrete can reliably protect power lines from deformation under the influence of bending loads.

The dimensions of the footrests F 3.05, which are determined by the series, are 2700 m. During installation, a significant part of the foundation height is buried in the ground. A foundation height of 1.7 meters is considered shortened and is indicated separately in the product labeling. The mass of a mushroom-shaped monolithic foundation is from 2900 kg.

The foundation of the power transmission line support is made of heavy-duty heavy concrete of class B25, the filler of such concrete is small crushed stone. Increased frost resistance of concrete foundations F grade F150-F200, water resistance W4-W6. A high class of water resistance allows the mushroom-shaped foundation to be exposed to aggressive chemical environments of water and soil. Special raised foundations are intended for use in water obstacles.

These properties allow such a support to serve for many decades without crumbling or allowing the structure to warp.

Reinforcement gives foundations a margin of safety. Reinforcement is carried out with longitudinal rods made of stressed steel reinforcement of classes A-I and A-III. The rods are welded into a single frame using binding wire. The protective layer of foundation concrete is at least 30 mm. The embedded parts and reinforcement products of mushroom-shaped foundations are pre-treated with two layers of zinc-rich primer against corrosion.

Product marking

The symbol consists of the designation of the product name, its standard size and additional characteristics. O – the purpose of the footrest is for corner supports on guy wires, A – for anchor-corner supports. Elevated ones are designated by the letter P.

For an example of brand decoding, consider F 3-05 , Where:

• F – mushroom-shaped footstool;
• Number – standard size;
• 0 - intended for corner supports on guy wires;
• 5 - voltage 500 kV;
• K - shortened.

The weight, code and date of manufacture of the foundation are marked on each product.

Foundation installation

In areas with clay grants, a sandy or crushed stone foundation 50-100 mm thick is used for the foundation. Often, crushed stone preparation is arranged under the foundation, which increases the supporting area. Under foundations for inclined racks, a crushed stone layer for soft soils is also made at an angle to the plane. The installation and lifting of the mushroom-shaped foundation F occurs using the mounting loops embedded in the structure of the block.

Product quality control

The filigree accuracy of the overall dimensions of the power transmission line foundation may not be achieved during production. However, the deviation in product dimensions should not exceed 10-20 mm in length and 5-8 mm in thickness.

The main role in the foundation is played by its mass; the more massive the mushroom-shaped foundation, the greater the load it can withstand. Therefore, the deviation from its design mass should not be less than 5-7%. To ensure that the concrete foundation does not collapse prematurely, attention is also paid to the quality of its concrete surface. Like any other reinforced concrete products, power transmission line foundations should not have a large number of cracks more than 0.2 mm wide. Shells more than 1 by 2 meters in length are not allowed on the surface of the mushroom-shaped foundation. Under no circumstances should the working reinforcement of the foundation block F 3.05 be exposed.

All embedded products located on the surface are treated with paint and varnish, and in case of operation in aggressive environments they are additionally protected. The manufacturer assigns a warranty period of 12 months from the date of commissioning, but no later than 18 months from the date of manufacture.

During the procedure batch acceptance of transmission line foundations, the strength of concrete, the compliance of reinforcement products and mounting loops, the strength of welded joints, the accuracy of overall dimensions, the thickness of the protective layer of concrete to the reinforcement, the presence and width of possible cracks are checked. Mushroom foundations are checked by inspecting each product; special attention is paid to the quality of the foundation embedded products, because it is their reliable adhesion that guarantees the stability of the support. Certifies the quality of reinforced concrete foundations technical certificate, accompanying each party. It informs the consumer about the number of reinforced concrete products in the batch, the date of manufacture of the batch, the mass of the product, and also provides the release strength of the concrete and the grade of concrete for frost resistance and water resistance.

Storage and transportation

Power transmission line foundations, like many monolithic and massive reinforced concrete products, are stored in one row or according to a special storage scheme. Transportation of the product takes place either in railway cars or in high-capacity vehicles under conditions of very reliable fastening of the products.

Reinforced concrete unified foundation structures are widely used in the construction of foundations for power transmission line supports. The developed foundation structures make it possible to construct foundations for all types of standardized supports of 35-500 kV overhead lines in any, even weak, soils.

Dear Clients! The Elektropostavka company sells and delivers to the installation site mushroom-shaped footrests, reinforced concrete piles and grillages, surface foundation structures, attachments, anchors for fastening guy wires, as well as foundation structures to increase the strength of embedding in soft soils: crossbars, support, backing slabs. When preparing applications for the supply of reinforced concrete foundations for power transmission line supports, it is necessary to indicate not only the full markings, but also the place of delivery of the goods.

Mushroom-shaped foundations for standardized metal supports of 35-500 kV power lines, manufactured according to the 3.407-115 series, are divided into two groups: the main range of structures - conventional monolithic mushroom-shaped footstools with inclined and vertical posts; composite monolithic mushroom-shaped foundations with suspended slabs; additional range of designs - footrests with a modernized headrest for anchor-corner supports; composite foundations with a bolted or welded connection between the bottom and the post. Interpretation of foundation markings according to series 3.407-115 ...

Unified composite foundations for steel supports of 35-500 kV power lines are manufactured according to the 3.407.1-144 series, designed to replace the mushroom-shaped foundations according to the 3.407-115 series.

Composite foundations (footboards) are designed to secure free-standing steel supports of 35-500 kV power lines and are assembled from separate reinforced concrete racks and slabs, which are connected at the installation site with two keys. Foundation replacement tables. Explanation of foundation markings according to series 3.407.1-144 ...

Mushroom-shaped foundations for metal supports of 35-500 kV overhead lines, developed according to project No. 13478tm, are manufactured in foundation formworks of series 3.407-115 issue 1 in accordance with TU 5800-001-00113371-2001. Project 13478tm “Modernization of foundation structures manufactured by JSC Svetlogorsk ZhBIiK” was carried out by the Sevzapenergosetproekt Research Institute, St. Petersburg, taking into account the technological features of the manufacturer. Compliance tables for standard foundations. Interpretation of foundation markings for project No. 13478tm...

Reinforced concrete piles of square section are standard structures and are made from ordinary vibrated reinforced concrete according to working drawings of series 3.407-115 issue 4, in accordance with TU 5800-001-00113377-2001. The piles developed in this project make it possible to construct foundations for all types of standardized supports of 35-500 kV overhead lines in any, even weak, soils. Pile foundations are made in the form of clusters of piles with steel grillages, or in the form of single piles. 5 standard sizes of square piles have been developed: 25x25 cm - 6 and 8 m long; 35x35 cm - length 8, 10 and 12 m, each has 2 reinforcement options.

Reinforced concrete piles of square cross-section are made from vibrated prestressed and non-prestressed reinforced concrete in accordance with the working drawings of structures of series 3.407.9-146 issue 2 and are used in foundations for steel supports of power lines of 35-500 kV. 4 standard sizes of piles of square section 35x35 cm, length 6, 8, 10, 12 m with two types of reinforcement, with prestressed and non-prestressed reinforcement - a total of 14 grades of piles were developed. The main range of piles is reinforced with prestressed longitudinal reinforcement of class A-V. Additional - non-stressed reinforcement of class A-III. Decoding the marking of piles SN series 3.407.9-146...

Reinforced concrete piles of square cross-section are made from ordinary vibrated reinforced concrete in accordance with TU 5817-004-01374760-2005 and working drawings of the structures of project No. 12614tm-t1 “Special vibrated piles for the foundations of overhead transmission line supports being built in Western Siberia.” Foundation piles for standardized overhead line supports are used in any soil conditions, including deep swamps. The decoding of the symbol for piles according to project 12614tm-t1 is similar to series 3.407-115 issue 4 with the exception of the marking of the head: Нр - head with one bolt for fastening the grillage, and the shoes of the steel supports of the contact network.

Reinforced concrete crossbars for securing supports of 35-750 kV overhead lines are used to increase the lateral surface of foundations and the underground part of reinforced concrete racks. Their use increases the load-bearing capacity of structures under horizontal (overturning) loads. The crossbar is secured to the rack or foundation using special fastening parts (clamps). Crossbars for electrical network construction are standard designs and are produced in accordance with standard designs: 3.407-115 and 3.407.9-158. Decoding the markings of crossbars...

Anchor, support, backing slabs are standard structures and are made of ordinary vibrated reinforced concrete according to working drawings of series 3.407-115 issue 5. PA anchor slabs are made in the form of rectangular structures with a central longitudinal rib. Anchor plates are used to secure guy wires for overhead line supports in the ground. OP support plates are designed to increase the supporting area in soft soils of reinforced concrete pillars of overhead line supports, and are square slabs with a cup for installing the pillar. PP1-A backing slabs are manufactured in the form of flat, rectangular structures, and are installed under heavily loaded pressed foundations in soft soils.

Reinforced concrete attachments of the PT type are intended for securing supports of overhead lines with a voltage of 0.38-35 kV, as well as telephone and telegraph communication lines. Attachments are used in both wooden and reinforced concrete supports in accordance with the design. Attachments are made of heavy vibrated reinforced concrete in accordance with GOST 14295-75 and according to working drawings of standard structures of the 3.407-57/87 series. Loading standards...

A similar design of mushroom-shaped columnar foundations has been used by our author Maksimych for many years. The difference between his method is that he makes the entire product - the cap, and then the stem - on the ground, and only then lowers it into the finished well. Such a technology in dacha conditions is the only possible one if the groundwater in the area is so close that it begins to fill the well already during the process of drilling it.

A similar design of mushroom-shaped columnar foundations has been used by our author Maksimych for many years. The difference between his method is that he makes the entire product - the cap, and then the stem - on the ground, and only then lowers it into the finished well. Such a technology in dacha conditions is the only possible one if the groundwater in the area is so close that it begins to fill the well already during the process of drilling it.

It’s not difficult to make these “mushrooms” yourself. A circle is drawn on a wooden pallet (several if space allows) with a diameter of 30 cm - the optimal size for a mushroom cap. A smaller diameter is ineffective, while a larger diameter makes manual drilling very difficult.

8-16 nails without heads are evenly driven along the contour of the circle. From the inside, a strip of formwork 12 cm high made of roofing iron or a rubber mat, or, in extreme cases, a double layer of roofing felt, is leaned against them. A reinforcing mesh is laid inside the circle and filled with M-150 sand concrete (three buckets of sand per bucket of M-500 cement). During the concreting process, a second mesh is laid. Reinforcement rods Ø 10-12 mm are inserted into the fresh mixture for the future connection of the “cap” of the mushroom with the “leg” - the foundation pillar. Any metal waste is suitable for the reinforcement.

After the sand concrete of the “hat”-shoe has set, the upper part of the foundation - the “leg” - is placed on it. as formwork for which you can use an asbestos-cement pipe with a diameter of 10 cm, a sheet of roofing iron or roofing felt rolled into a tube. When filling a pipe that remains with a cap, the mixture can be weaker - M-100, and with removable formwork - roofing felt, iron - at least M-150.

How many mushroom-shaped foundations are needed for a particular structure? Using reference books and many years of experience, Maksimych eventually determined the permissible load on one mushroom-shaped foundation for the marshy soils of the Moscow region. It turned out to be equal to 0.6 kg/cm2. With a cap diameter of 30 cm, its area is 700 cm2, which means it can be loaded with 420 kilograms. So, for example, the total mass of the future bathhouse together with tanks filled with water and the estimated weight of snow on the roof was determined to be 12 tons. Dividing this weight by 0.42 (the load-bearing capacity of one “mushroom”) we got 28—the number of mushroom-shaped foundations.

By the way, I would like to note that a mushroom-shaped foundation has an advantage over a columnar foundation not only in that its support area is larger due to the cap and this prevents the foundation from sagging. The same cap, in the case of individual seasonal swelling, holds the post in the ground like an anchor and does not let it go up.