The characteristics of concrete monoliths largely depend on the quality of the reinforcement, which distributes static and dynamic loads. Therefore, it must be correctly oriented in the thickness of the structural element and reliably protected from the external environment with a layer of concrete. For this purpose, reinforcement clamps are used - embedded elements designed to secure and hold the reinforcing structure until the concrete solution sets.
Protective layer of concrete and its functions
The distinctive properties of reinforced concrete are explained by the unique combination of physical and chemical properties of its components. The metal frame works in tension, while the concrete mass has high compressive strength. They have the same coefficient of thermal expansion. The hardened solution turns into an array of artificial stone with an alkaline environment, which becomes an excellent insulator for steel frame elements from corrosion. This insulation is effective when, after concreting, the distance between the reinforcement bars and the surface of the finished product is sufficient to prevent the penetration of water, oxygen, and other aggressive substances through the pores of the concrete to the surface of the metal products. The minimum value of this distance (usually 10-40 mm), called a protective layer, depends on the conditions of further operation of the reinforced concrete product or structure and the influence of various factors.
Compliance with the protective layer is a guarantee of the strength and reliability of the structure being built.
Building codes define the requirements for the thickness of the protective layer. After all, a thick layer increases the load on the frame, increases the weight of the structure and is more expensive, while a thin layer partially loses its functional characteristics. Determining the required concrete thickness is influenced by:
- type of structure being built (wall, column, staircase, foundation, ceiling);
- diameter of the reinforcement used;
- external environment and climatic zone (temperature range, maximums and differences; humidity; contact with the ground and others).
According to the standards, in the most common cases, the following recommendations on its thickness are relevant for regulating the protective layer of concrete:
- rooms with normal or low humidity - at least 20 mm;
- wet rooms without waterproofing – 25 mm or more;
- unprotected external surfaces of buildings - at least 30-40 mm;
- part of the structure buried in the ground that does not have additional protection – 40-76 mm;
- foundation – from 40 mm;
- floors up to 25 cm thick - from 12 mm; more thickened - from 17 mm.
Special magnetic control sensors help to find out the actual depth of reinforcement in finished reinforced concrete structures.
DIY supports for fittings
reinforcing the foundation reasonably arises . This is exactly what this article will discuss. Let me remind you that how to make formwork for the foundation with your own hands was described in detail in the corresponding article.
As for the actual reinforcement of the foundation, the main attention will be paid to the method of tying and laying the reinforcement, as well as the list of necessary tools and devices.
Methods of tying and bending reinforcing bars
The most common method of tying reinforcement in individual construction is hand tying. There is no need to buy a special tool. There are several knitting techniques. In all cases, the first loop should be placed along the spiral grooves, since with such a connection the reinforcing bars hold better and do not dangle. The main knitting methods are given below:
- Wire knitting.
This is a simple method that does not require special explanations or skills. For reinforcement ø12 mm, cut wire 180-200 mm long and bend it in half. The wire is wrapped around the fastened elements so that both free ends are 30-50 mm long. Holding the loose ends with one hand, insert the crochet hook into the loop with the other and twist the wire with rotational movements of both hands.
- Connection with reinforcement clips
(can be bought in a store). This method is good for connecting reinforcement in hard-to-reach places. As can be seen from the picture, a paper clip made of spring steel is fixed in diameter on one rod, and with its other end it presses another reinforcement. Fast and convenient!
- Overlapping connection.
It is used to lengthen the reinforcement frame and at the nodal points of the foundation walls. The recommended overlap length should be about 30 reinforcement diameters. For example, with a rod diameter of 10 mm, its length should be 300 mm. - To bend the rods we will use the simplest device. It can be made from two steel pipes with an internal diameter of 20-30 mm, a length of 500 mm and 800-1000 mm.
In a short pipe, starting from its end, use a grinder to cut off two symmetrical flats 80-100 mm long so that the height of the cut part of the pipe is within 18-20 mm. The result should be two cylindrical surfaces.
We will bend them outward at an angle of 90˚ relative to the longitudinal axis of the pipe. It is important to ensure that the transition from the pipe to the bent ends is made within the radius.
If you preheat them with a blowtorch or gas torch, this can be done easily.
Inserting one end of the reinforcement into a short pipe, and a long pipe into the other end, bend the reinforcement at the desired angle. In this case, the bent part of the short pipe will act as a radius stop.
If we bend the second cut part in a short pipe, and process the second end of the pipe in the same way, then we will get a device with four stops.
When bending reinforcement, you can use any of them.
Finally, you should think about securely securing the device to some stable base. To give additional strength to the stops, you can insert a wooden spacer between them.
How to reinforce the foundation for a bathhouse
Before pouring the foundation, you must remember to mark and cut holes in the formwork for plastic tubes for ventilation of the underground space of the bathhouse and laying utilities. For water and sewerage - the lower, the better, since in winter it will not freeze.
Manufacturing of reinforcement cage
You will need to make a template according to which the reinforcement cage will be assembled. Its design is quite simple and can be done by anyone. Frames for foundation reinforcement are assembled in a convenient place. Their length depends on the length of the reinforcement and the structural dimensions of the foundation. The finished structures are placed in formwork and tied together with wire.
Particular attention should be paid to the corner and internal intersections of the bathhouse foundation walls. In these places, the reinforcing bars are bent at 90° and overlapped with each other. The remaining node connections are connected crosswise with wire in the usual way. The design of the template is shown in these sketches:
Laying reinforcement in formwork
An important condition for reinforcing a strip foundation is that the reinforcement should not touch the walls of the formwork. That is why it is necessary to provide gaps within 50-70 mm between the frame and the outer surfaces of the foundation walls, including its sole (base). This forms a protective layer against rust and other harmful atmospheric influences.
The frame in the formwork must be so stable that it does not move from its place when poured with concrete. To do this, star-shaped clamps are put on the vertical rods, and special bosses (stands) are placed under the lower rods, which ensure the stability of the frame and the necessary clearance.
When building a bathhouse, you can simplify this process and place broken bricks or stones underneath. And to ensure side gaps, tie in increments of 2-2.
5 meter transverse rods 10-15 mm long less than the internal width of the formwork. They will then act as clamps.
This method is quite acceptable, but will not provide the same accuracy as when using special clamps and stands.
Tips and tricks
- Before laying the reinforcement in the formwork, it should be cleared of dirt, debris and unnecessary objects.
- Reinforcing bars are cleaned of rust, scale and dirt. It should be stored on wooden stands under a canopy, excluding exposure to precipitation.
- The blanks are marked with chalk, along which they are cut or bent.
- It is advisable to photograph the results of the work. These pictures may be useful in the future.
- It must be borne in mind that when purchasing fittings, the presence of rust on it is not a defect.
- The permissible deviation in curvature when purchasing reinforcement should be within ±6 mm per linear meter.
- The standard consumption of reinforcement in individual construction is 50-80 kg per cubic meter of concrete.
So, we have reinforced the foundation
under a log bathhouse.
In the following articles from the series on how to build a bathhouse with your own hands, we will consider questions about pouring the foundation with concrete and waterproofing it.
DIY strip foundation
The foundation is the foundation for any structure, be it outbuildings, a one-story country house or a large industrial facility. The choice of foundation type depends on a number of aspects:
- functional purpose of the building;
- size and number of floors of the building;
- total load on the foundation;
- features of the relief and soil type;
- climatic conditions of the region;
- seismic activity;
- budget possibilities.
For example, if you are planning to build a foundation for a bathhouse from timber or rounded logs, the optimal solution would be a shallow strip foundation . Its design and construction is not very expensive in terms of time and money, but it is a completely reliable basis for not too heavy wooden and brick buildings.
Soil requirements
Strip foundations for bathhouses and other private buildings can be erected on dry and non-flowing stable soils. If the soil on your site is heaving and freezes to a great depth in winter, you will have to spend more time, effort and money on excavation work and reinforcement of the foundation, and perhaps choose a different type - for example, a pile foundation.
Construction site preparation
The strip foundation is erected on an area that has been previously cleared of vegetation, debris and topsoil - grass cover. If during the preparation of the site you come across fragments of bricks and stones, do not rush to throw them away: in the future you will need raw materials for use as a concrete mortar compactor.
Territory marking
Before you begin construction of the foundation, the design of the building, in our case a bathhouse, must be completely completed. Having a detailed drawing in front of you, you can proceed to marking the site. To do this you will need a tape measure, a square, a non-stretch cord, and pegs.
First, the outer perimeter of the structure is marked. It is very important to maintain a 90° angle between adjacent walls, of course, unless otherwise provided by your project. To check whether the outer perimeter lines are perpendicular to each other, compare the two diagonals: the deviation should not exceed 20 mm.
Next, mark the internal perimeter and location of the walls inside the building. For buildings made of timber, the thickness of the foundation should be about 30 cm, and for brickwork - 35-40 cm.
What provides the protective layer?
The location of the elements of the reinforcing frame before concreting can be verified, maintaining the required distance to the walls of the formwork and the base. But the possibility of displacement of individual elements from the flow of fresh concrete when filling and compacting the volume cannot be ruled out. At all stages of obtaining a reinforced concrete structure, the position of the metal elements and the entire frame will remain stable if clamps of the protective layer of reinforcement are used. The saying about a small, but no less expensive, spool is very relevant when applied to them.
Positive qualities of products and benefits from their use:
- The clamps are made of durable plastic - a material that is resistant to corrosion, temperature changes, and the effects of aggressive substances.
- The strength of the products allows you to maintain stability of geometric shape and size, and create a reinforced reinforcing frame for loaded structures.
- Versatility - they can be selected for any type and size of reinforcement, various methods of its fastening, and ensuring the required thickness of the protective concrete layer.
- Plastic supports for reinforcement are also used when concreting structures with a frame base made of composite materials.
- Mass produced retainers are interchangeable.
- The metal frame of the future reinforced concrete structure is assembled easily, quickly, without the use of welding or wire to fix a certain position of the rods relative to each other and the formwork.
- They prevent the frame mesh from appearing above the concrete surface and keep it in a fixed position.
- Support for metal reinforcement prevents concrete from cracking because it minimizes bending and deformation of the rods under the significant weight of the structure.
- They help maintain a constant required thickness of the protective layer.
Made from plastic, the fasteners are a consumable item that remains in the poured concrete. Very rarely, being an element of the formwork, the support for the reinforcement can be reusable. Working with such a product (for example, a cone-type reinforcement clamp) involves dismantling and filling the remaining cavity with solution.
The orientation of the reinforcement affects the classification of the fasteners used with it, which can be:
- support – to fix the position of the frame in the horizontal plane;
- wall - for vertically directed reinforcement (the most used is the star reinforcement clamp);
- universal – combining the capabilities of the first types;
- special - for use in special cases and specific situations; Such fasteners include plugs and tubes, which create the necessary cavity in the concrete and provide the required distance to the reinforcement from the surface of the future product.
The optimal principle for placing clamps in the body of the future product is a checkerboard pattern. With this arrangement, the recommended interval between them is 50-90 cm. The specific value is selected taking into account the dimensions of the metal frame, the cross-section of its rods and the design features of the clamps themselves. According to building regulations, the usual consumption of reinforcement clamps is 4-10 pcs/m2.
Mesh on plastic supports for reinforcement, arranged in a checkerboard pattern, every 80 cm, consumption 5 pieces per square meter.
Do-it-yourself reinforcement clamps: types and rules of application
The characteristics of the concrete base depend on the quality of the reinforcement. Uniform installation within a concrete structure increases reliability.
The layer of concrete increases, protecting the reinforcing mesh from rust; a level installation assumes an even distribution of the load over the surface. A reinforcement clamp will help you cope.
Keeps the metal structure at a distance from the formwork.
Stand for fittings
Features, Benefits
During reinforcement, additional parts are used - stands for attaching metal rods. They are made of plastic and are called retainers. They have good technical performance and are in demand:
- Eco-friendly.
- Withstands exposure to ultraviolet rays and low temperatures.
- Inert to alkaline, aggressive environments.
- Versatile.
An important point is that they can be used for any type of concrete base.
Purpose - to provide gaps between the surface of concrete and the reinforcing frame. Advantages:
- Possibility of filling with mortar, part of the structure will not budge.
- It is possible to maintain the distance from the surface to the reinforcing frame; the metal is not subject to corrosive damage.
- Plastic products provide stability to the reinforcement frame.
- It is possible to increase the service life of metal products.
Classification, limits of application
Reinforcing structure fasteners can be used in several structures:
- When forming floor slabs.
- For the construction of walls.
- While pouring the foundation.
When creating a columnar, bored foundation, star-shaped fixing elements are used. The structure is a mesh element through which the concrete mixture flows freely.
When installing horizontal reinforcing structures, “racks” are used. It is possible to provide a protective layer thickness of 15-35 mm, with a reinforcement diameter of 19-25 mm.
If a preliminary concrete surface has been prepared, you can use a “chair”. It has good load-bearing capacity and is used when installing high-thickness monolithic slabs. Provides a protective layer of 15-60 mm, with a section diameter of 14-24 mm.
On unstable surfaces, such as crushed stone, sand cushions, “pyramid” models are used. They can withstand a concrete layer of 15-90 mm, with a reinforcement diameter of up to 16 mm.
Choice, installation features
“Stars” are popular – they are universal.
When choosing an “asterisk” as a fastening element, consider the quality of the material. Poorly made fasteners have a short service life and break into several parts upon first use.
Consider the thickness of the product and the quality of workmanship. It should be flexible and not break when pressed. A simple method is to put the part on an object corresponding to the cross-sectional diameter of the reinforcing rod. If the product has retained its integrity, it can be used when fixing reinforcing rods.
Basic requirements for fasteners for reinforcement
Must be made of durable material. The quality determines how heavy loads a concrete foundation can withstand. To check the chair and cube, just stand on them. If they remain intact, slightly deformed, this is normal.
Elements that are installed on the ground require additional parts - stands to reduce pressure.
From pipe scraps
You can take a piece of plastic pipe and drill holes on the sides to install the clamp on the crosshairs of the reinforcing mesh. The fixing element can be used to hold one rod; you will have to drill not four holes, but two.
From a rod
The “frog” is installed between the reinforcing mesh to secure the top row. The product provides additional strength to the entire structure. When compared with tying a reinforcing structure onto “soldiers” (vertically installed scraps of metal rods), the method significantly speeds up installation.
Made from rod and metal rings
It looks like a “frog”, but has differences - a metal rod, which is installed in a ring of the same material, is poured with concrete. Used to secure the top floor of the reinforcing mesh. The fixing element is a ring. Reinforcing mesh is laid on it. At the bottom, a U-shaped rod is attached to the metal frame.
What fasteners should not be made from
Bad materials for parts are wood: stands made of small planks, installed pegs, multilayer plywood laid with plates, chipboard. Reasons: wood absorbs moisture very strongly and can affect the quality of concrete due to rapid drying; has poor strength, soaked in moisture, it only gets worse.
You cannot use plastic bottles; they have poor load-bearing capacity; when pouring concrete, the bottle will be crushed.
Brick is not the best option. Reasons: absorbs liquid and breaks down over time.
A little conclusion
Thanks to clamps for the reinforcing frame, the quality of concrete structures can be significantly improved. By installing plastic products, the protective layer increases, which protects the reinforcement from premature aging and gives the structure strength. The concrete mixture is evenly distributed over the surface, filling the voids.
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Types of fasteners
Manufacturers present an impressive range of products of various types. The production of plastic fasteners for fittings is constantly introducing new developments. Already well-known designs are being refined and improved. Let's take a closer look at the most popular of them.
"Cube"
A universal embedded element that can withstand heavy loads due to its thickened wall. A reinforced version of the clamps can serve as a support for reinforcement with a diameter of up to 40 mm, and provide a protective layer from 35 to 80 mm. The most popular is the cube retainer with a wall thickness of 2.1 mm, provides a protective layer of 35, 40, 45 and 50 mm in size, and is used for reinforcement with a diameter of no more than 28 mm.
"High Chair"
The most common support clamps for metal reinforcement when reinforcing ceilings, floors and other horizontal planes. The shape is a cylindrical barrel with four grooves and open bridges at the top. The usual version has 4 legs, the reinforced version has 5. The fixture for the reinforcement is a “chair”, has a fixed size, and can provide a protective layer in sizes of 15, 20, 25, 30, 35 and 40 mm, the choice of the required size is carried out according to the requirements of the drawing structural reinforcement. This type of clamp is suitable for fittings with a diameter of 4 to 14 mm.
"Herringbone"
A modified version of the chair, which has 2 pairs of inclined bars at the top. The products allow you to obtain 4 different layers of the required concrete protection - 20, 25, 30 and 35 mm. Suitable for metal rods with a diameter of up to 20 mm.
"Cone"
The clamp is installed at the ends of the tube. The role of the tube is to form a through hole in the mass of poured concrete for the formwork tie bolt. The function of the cone is to prevent concrete from getting inside the tube. After removing the formwork, the cone can be reused.
"Star"
A common product in monolithic construction, which received this name due to its star-like appearance. Designed for vertical fixation of the reinforcing frame and creating a gap between it and the formwork. The star lock helps to obtain one option for the thickness of concrete protection, ranging from 15 to 75 mm. Used for fittings with a diameter from 4 to 22 mm.
"Rack"
The cylindrical reinforcement clamp rack is very similar to a cube. By installing it on top of each other, you can hold several rows of reinforcing mesh at one point, but at different levels.
Important! If the concrete surface will be formed on a layer of waterproofing or on a loose base, it is recommended to use an additional “base” fixer. It prevents the supporting legs or body of the main product from breaking through the waterproofing layer; prevents unwanted immersion of the fixer into loose sand or gravel with the inevitable disruption of the uniformity of the protective layer in this area.
Homemade clamps and supports for reinforcement
The desire to save money, small volumes of individual construction, the impossibility of purchasing or the urgency of completing the work encourages the use of improvised means (brick, paving slabs, wooden beams, paving stones) and various devices made independently as a stand for fittings.
Note! Wood and brick have increased water absorption. Wooden blocks also swell subsequently, and in the future they generally collapse. Therefore, such options for stands are unacceptable, since in the area where they are installed, the reinforced concrete structure loses its reliability.
Often bars or elements of the desired shape are cast from concrete. Their advantages are good adhesion to poured concrete due to the same structure, very high strength indicators. The main disadvantage is that the support does not reliably fix the frame, which can move when the solution is supplied to the work area.
Craftsmen can also use the following self-made fasteners for fittings:
- a plastic retainer made from a sewer plastic pipe in which the necessary grooves or holes are made for laying the fittings;
- socket boxes with and without cuts for fixing fittings.
Plastic embedded clamps simplify the process of self-assembly of a metal reinforcing frame and significantly speed it up. After pouring concrete, the frame has a guaranteed protective layer on all sides. This is the key to long and safe operation of the resulting reinforced concrete structure or its individual element. And simple plastic fixtures for fittings help achieve this result.
Various plastic adapters work well in tandem with the protective layer clamps. They increase the supporting area of the frame on loose surfaces, help regulate the size of the concrete protection layer, and expand the possibilities for optimal use of standard fasteners without the cost of additional highly specialized products.
Fasteners for fittings: purpose and types, features of choice
The characteristics of concrete monoliths largely depend on the quality of the reinforcement, which distributes static and dynamic loads.
Therefore, it must be correctly oriented in the thickness of the structural element and reliably protected from the external environment with a layer of concrete.
For this purpose, reinforcement clamps are used - embedded elements designed to secure and hold the reinforcing structure until the concrete solution sets.
Tasks of clamps
The main function of the frame and protective layer clamps is to maintain the correct position of the reinforcement inside the concrete monolith. The embedded elements installed before pouring remain in the mortar after it hardens.
This is a consumable item, so their price should be low. Correctly installed clamps for the frame reinforcement and protective layer significantly speed up and simplify concreting and ensure uniform distribution of the load on the frame.
Types of fastenings
The clamps are made of durable plastic that is resistant to aggressive influences. This ensures the required performance indicators and an acceptable price for the material. Less commonly used are elements that are parts of the formwork, after removing which the resulting cavities must be filled with concrete. There are different types of clamps based on the location of the reinforcement they hold:
- Supporting – for fixing the reinforcement frame horizontally, for example, a cube, a chair;
- Wall - designed for fastening vertical conductors, for example, an asterisk;
- Universal – combines the characteristics of horizontal and vertical options;
- Special - used in cases to create cavities in a concrete monolith, for example, tubes and plugs.
"High Chair"
This is the most popular type of clamps for horizontal fittings. It is used when pouring floors, slabs, and other elements with large loaded surfaces.
The universal shape of the fastener for “chair” type fittings is a cylinder with four cut grooves and upper crossbars. The standard design has four legs, the reinforced design has five.
This type reliably holds metal elements with a diameter of 4-16 mm, allowing a layer of mortar of 15-40 mm above them.
To use clamps on loose soils, they are supplemented with a base element that prevents them from sinking.
It is also used in cases where waterproofing material is laid under a metal frame so that the legs do not break through it when pouring.
There is a modernized version of this element, called “herringbone” with 4 inclined jumpers, with the possibility of laying protection with a thickness of 20 to 35 mm.
"Cube"
“Cube” fastenings are designed for fastening reinforcing elements of foundations, horizontal floors and bridges. Its body can be installed so as to obtain the required distance between the frame elements and the required protective layer. According to SNiP standards, depending on the diameter of the metal rod, 6-10 attachment points are installed per square meter.
Several sizes of the “cube” clamp are offered for horizontal fittings, depending on the connectors and the thickness of the plastic wall. By installing it on different faces, you can achieve a protective layer thickness of 35-80 mm and fix a rod with a diameter of up to 40 mm.
"Cone"
Clamps for cone-type reinforcement are installed at the ends of the stop tubes through which the tie bolts pass and rest against the formwork, preventing solution from entering the tube.
Failure to use these embeds will result in the loss of tie bolts, which will fall into the thickness of the hardened concrete. For each of these bolts you will need two plastic tips, which are removed after dismantling the formwork and can be reused.
You can avoid conical clamps by using reinforcement with clamps to hold the formwork, but this will cost more.
"Rack"
The design of the “stand” reinforcement clamp is similar to a “cube”. It has a cylindrical shape that can withstand heavy loads. It is well suited for the lower rows of reinforcement, for loose soil; it is additionally equipped with a “base” element, which reduces the pressure on the surface.
The “stand” reinforcement clamp is designed for horizontal surfaces and is attached to reinforcement with a diameter of up to 16 mm. With its help, you can create reinforced structures with a protective layer of 12-40 mm.
Using special fasteners, the rack can support several rows of reinforcement cage, while maintaining the overall level of the structure.
Material consumption, as for other horizontal models, is 6-10 elements per square meter.
"Star"
Star reinforcement clamps are of the vertical type, but can also be attached to horizontal reinforcement levels. It snaps onto a metal rod and, in accordance with its own diameter, allows the application of a uniform protective layer 15-75 mm thick.
This type of fastening securely snaps onto reinforcement with a diameter of up to 22 mm, suitable for walls, columns, and other concrete structures with vertical surfaces. Consumption, depending on the type of surface, is from 4 to 8 elements per square meter.
Multi-level
Clamps for multi-level fittings are gaining popularity due to their versatility and low price. Technologically, they are simple clamps connected by special fasteners.
This design allows you to strengthen several levels of reinforcement, connecting them to each other, increasing the strength and reliability of the monolith by increasing the protective layer.
The consumption of embedded elements remains standard - up to 10 per square meter.
Elements of the “chair” or “cube” type are often used as multi-level clamps. This is possible when they are equipped with fastenings that allow them to be built up into several floors, like a construction set. The clamps fixed in the grooves easily withstand increased loads, do not move or burst when pouring concrete.
Do-it-yourself reinforcement clamps
In private construction, when performing small volumes of work, it is possible to use homemade clamps for the protective layer of reinforcement. Often, available materials such as bricks, wooden supports, stone, and tiles are used for this.
The worst option is wooden elements that are too hygroscopic. They change shape, as a result, the integrity of the reinforcement frame is violated, and over time they collapse, leaving voids unforeseen in the design. After this, cracks appear in the concrete and its strength decreases significantly. Another unsuccessful material is plastic bottles, which deform under load.
Previously, separately cast concrete elements in the form of cubes or parallelepipeds were used to create a protective layer. They adhere well to the monolith, maintaining its strength characteristics, but cannot secure the reinforcement firmly enough, often shifting during pouring, preventing the load from being evenly distributed. Therefore, they are now being abandoned, installed only in extreme cases.
High-quality hand-made reinforcement clamps are almost as good as industrial ones and are made from cheap improvised materials:
- Plastic pipe. It must be strong enough, resistant to corrosion, and easy to handle with tools. This allows you to make the necessary holes and clamps for fittings in it.
- Plastic socket boxes with specially made cuts.
- Metal rod. It is used in private construction with small loads on reinforced concrete mass. Among builders, this species was called “frog”.
- Structures made of metal rods and rings. This is one of the types of “frog” - a rod is inserted into the ring and the solution is poured. After this, the entire concrete monolith is made.
Selection and installation features
The first criterion for choosing fasteners for fittings is the type. Popular star-type reinforcement clamps are a universal solution for fastening vertical and horizontal arrays of metal rods.
This element is very demanding on the quality of the material from which it is made, since when fastened, low-quality sprockets split into several parts.
Therefore, when choosing, you need to ensure that the plastic is sufficiently thick and of its quality; it must be durable and elastic.
The most reliable test is to simply put the clamp on an object of suitable diameter for the fitting. If it does not collapse, it can be used in construction.
When selecting clamps for horizontal structures, you need to check their strength, since they experience high loads. To check the “cube” and “chair” you just need to stand up these elements; under the weight they may be slightly deformed, but not burst.
We must not forget that when strengthening reinforcement on the ground, the fastening parts must be equipped with additional elements - supports. They reduce the pressure of the structure and do not sink into the ground, leaving the metal above the surface.
As a result, it is completely covered with the solution and does not corrode, which extends its service life.
For all types of clamps, the core diameter is important. Select by markings - FS30 for a rod of 30 mm, FS50 for a diameter of 50 mm, etc. It is important to immediately calculate the number of fasteners per linear or square meter.
According to GOST, the number of these elements per m² should be in the range of 4-10 pieces. It must be taken into account that the fewer fasteners you have to use, the stronger the reinforced concrete structure will be.
At the same time, their insufficient quantity will lead to a violation of the integrity of the reinforcement and a decrease in the quality of the protective layer.
Calculator
Use an online calculator to calculate the required number of fasteners and their cost.
The technology of using fasteners for the protective layer of reinforcement can significantly improve the quality of reinforced concrete structures. Uniform distribution of mechanical stress in the middle of the structure and a high-quality protective layer extend the service life of the concrete monolith and make it resistant to corrosion.
Choosing fasteners - advice from an expert
In my 10 years of practice in monolithic construction, I quite often encountered the problem of defective fasteners. After installing them under the reinforcing mesh, and then stepping on it, the stands simply scattered to the sides. They broke in half, and the mesh was lowered onto the formwork. There was also a case with the “star” fasteners; during installation on the reinforcing mesh, they simply flew apart, half the bag was simply thrown into the air. The problem was low-quality plastic; it was fragile.
When purchasing, I advise you to open the bag with plastic stands and check them. If it's a chair, stand on it, it shouldn't break, it might just bend. The fastener is an asterisk, try to put it on something of a suitable diameter, bend it, it should not break. Plastic must be flexible and at the same time strong. If everything is ok, buy it.
Currently, the range of fasteners for fittings is simply huge, and every year it is growing all the time. New companies, new forms appear, but their goal remains the same, which is to provide the necessary protective layer to the reinforcement so that the structure you are building is strong and reliable.
Clamps for wall panels
"Star" s/s 25 mm . One of the indispensable components of wall panels. It holds up well in the summer heat and is quite flexible in the cold season.
"Star" s/s 30 mm . Responsible for deepening reinforcement cages in vertical structures up to 30 mm. Main features:
- The asymmetry of the products made their protective properties the same along the entire perimeter;
- When constructing foundations or basement parts of buildings in which waterproofing is present, U-shaped petals prevent possible damage to the insulating ball;
- The petals are additionally reinforced with ribs, which allows them to withstand significant loads.
"Star" s/s 50 millimeters . These products are the largest in the line of known parts for creating protection for wall panels and columns. They are also used in the construction of strip foundations for buildings.
All parts are patented and have undergone a number of tests confirming their strength, reliability and durability.
