How to twist fittings correctly

Knitting reinforcement: methods, patterns, norms and rules of knitting for beginners

12.10.2018

Knitting reinforcement is one of the main stages of work to create a reinforcement frame. By connecting the reinforcement, a reinforcing structure is created, thanks to which the concrete receives greater strength in both compression and tension.

If the rods are connected incorrectly, the finished monolithic structure will not receive the design strength.

In order to avoid this, we will look at how to knit reinforcement correctly, observing all the rules and regulations, and what tool can be used to do the work; this will be useful for novice reinforcement makers and for experienced builders.

Methods of knitting reinforcement

Let's consider all the existing ways to connect reinforcement. Each of the options is good in some way, and is used by builders, depending on the type of building and design requirements. There are 3 ways to connect rods; with their help, a strong and reliable metal frame is created:

1. Wire knitting.
2. Welding.
3. Plastic clamps.

These methods of tying reinforcement have their own characteristics. Each of them is correct and is applied depending on the requirements and the material used. When reinforcing a strip foundation for a private house, the reinforcement is often connected by welding rather than tied with wire. But which option is the best?

Advantages and disadvantages of welding connections

Despite the fact that these are different technologies, the right choice can save money and time on construction, without sacrificing structural strength. The method of connecting elements by welding was previously considered one of the most reliable and effective. However, such technology is not always appropriate. Usually it was used when installing bulky frames that strengthen the foundation for multi-story buildings and large cottages.

This method has some disadvantages:

1. You need to have skills in working with a welding machine, otherwise you need to spend money on the services of a professional welder. In this case, the cost increases.
2. Welding points are the weak point of the structure. There the strength of the frame becomes lower.
3. The method is not suitable if you use fiberglass reinforcement. In addition, the A-400 (A-3) fittings, which are the most popular, cannot be connected by welding. Only rods with the index “C” are suitable for work, for example: A500C reinforcement.

Therefore, in modern monolithic construction, welding has been replaced by viscous welding. For private and residential houses, construction of a bathhouse, garage or other buildings, this is the best option for connecting reinforcement.

Pros and cons of joining using the knitting method

Why is this method so good? It has the following positive aspects:

1. Speed ​​of work completion. Knitting with wire takes little time, it is simple and does not require skills. However, if you do it manually, the process slows down. Next we will look at how to quickly knit reinforcement.
2. Ease of troubleshooting. When working with welding, it will be more difficult to eliminate errors; you will have to take a grinder and cut the welding seam. The wire can be simply bitten off with wire cutters or unwound with a crochet hook.
3. You don't need to be a professional to knit reinforcement.
4. The reinforcement process can be performed in formwork.
5. The cost of work is much lower.

An example of knitting a mesh of reinforcement with wire.

If we talk about shortcomings, we note the precariousness of the finished frame. True, this is not a big problem. The structure will be strong, the only problem is that when the frame is moved into the formwork it begins to loosen, in this case it is possible to tack the reinforcement in several places by welding.

To solve this problem with fiberglass reinforcement, you need to attach several braces to make the structure more rigid and stable. By bending, the tension in the knitting areas changes, the frame moves. Therefore, you need to be careful when installing it in the formwork.

It is better to knit the reinforcement in the formwork or above it if the strip foundation is being reinforced.

Features of connecting reinforcement with plastic clamps

The main advantages of this method are that it does not require special skills, it has a high speed of work, and reliable fixation of the reinforcement.
The disadvantages of this method are the following:

1. Price. For large volumes, the wire will be more economical.
2. Speed ​​of work (when compared with other methods of knitting).
3. Correction. You made a mistake somewhere, you will have to bite off the clamp, it becomes unusable, but the wire can be tied up.
4. Reliability. It is not advisable to move around a structure connected with plastic clamps.
5. Temperature. They burst at subzero temperatures.

Based on these data, we can say that this method is more suitable for private construction, with small volumes, and it is also suitable for people who want to do the reinforcement themselves with their own hands.

Tools for tying reinforcement, technology for working with them

Nobody does the work manually. It's practically impossible. There are special tools for this purpose that speed up and simplify the process. Each tool has its own characteristics of use. The following devices are available for tying reinforcement:

1. Hand hook.
2. Knitting gun.
3. Screwdriver.
4. Ticks.

Each of the tools has its own pros and cons, we will consider them, as well as the technology for their use, and based on these data and the opinion of an expert (a reinforcement specialist with 10 years of experience), we will summarize and choose the best option for tying reinforcement.

How to crochet reinforcement correctly?

The peculiarity of the work is that it is done manually. At first, the process will be lengthy, as you need to get better at it. The hook is made of steel, and the handle is made of wood or plastic. The cost of such a hook is 1 thousand rubles.

There are even automatic hooks on sale, but reviews about them are mixed. Some note the short lifespan, others say that it is difficult to twist wire 2 mm or more thick.

There are several options for connecting knots when crocheting reinforcement. Let's look at the most popular ones.

Simple crochet rebar tie knot

The most common and simplest knot is performed as follows:

1. To connect the rods to each other, you need to take a wire 15–20 cm long and bend it in half.
2. The bent wire is bent again, but not completely, you should get a hook.
3. We insert the wire under the reinforcement that needs to be tied.
4. Next comes the hook itself. You need to insert it into the resulting loop and hook the free end of the wire.
5. One revolution is made. It is important to hold the free end.
6. Pulling the hook towards you, twist the wire until it comes off.

Step-by-step diagram for making a simple crocheted reinforcement knot.

Note! In order not to buy a crochet hook, you can make it yourself. You will need a piece of steel rod, and the handle can be made of plastic or wood. Having done it once, you can constantly use the knitting tool. See step-by-step instructions for making a hook with your own hands here.

"Dead Knot"

This unit is used for reinforcing structures consisting of reinforcement bars and clamps, such as beams and columns. Since it reliably fixes the reinforcement into the corner of the clamp, reinforcement specialists called it a “dead” knot. To quickly and efficiently perform such a knot, you need to practice a lot. Consider the instructions for executing the node:

1. We take a wire 20–40 cm long, its size depends on the diameter of the reinforcement used, and bend it in half.
2. We run the wire, loop forward, under the bottom of the reinforcement to the left of the clamp, leaving 2–4 cm to complete the knot.
3. We bring the wire to the top of the clamp and bend it again under the bottom of the reinforcement.
4. Insert the hook into the loop and hook the free end of the wire.
5. We pull the hook towards ourselves and at the same time make several turns until we feel that the wire is clamped, or until the loop comes off.

Scheme of tying reinforcement with a “dead” knot using a hook.

It should be noted! In order for this knot to reliably fix the reinforcement into the corner of the clamp, the wire should be pressed as tightly as possible to the reinforcement and the corner of the clamp, otherwise the tie will turn out to be unreliable.

You can check the quality of the assembly by tugging the clamp with your hand; if it wobbles, it is done incorrectly or is not fully tightened. We tighten it or make an additional tie with a simple knot.

When performing reinforcement of complex structures, for example, semicircular beams, nodes can be combined. First, a “dead” knot is made, and then two simple crosswise ones, as in the photo below.

Special gun for mating

This is an ideal tool for tying reinforcement. It makes the process much faster and easier. It is most convenient to assemble a metal frame with it. The only caveat is that such a unit is not cheap. That's why it is used on large-scale construction projects. The minimum cost is 30 thousand rubles.

It looks like a regular drill. Only a roll of wire is inserted into it. To tie, you need to point the gun at the joint and pull the trigger. He will do the knitting himself in a matter of seconds. This is the simplest and most affordable option for tying reinforcement.

On a note! It takes 9 seconds to make 1 knot tied with a hook. If you take an automated hook, it will take 7 seconds. And tying with a gun takes only 1 second per 1 knot.

But this method also has its disadvantages:

1. Not everywhere they can get to perform mating.
2. Price.
3. When you fix the reinforcement, you can no longer untie the knot with a crochet hook.
4. You cannot knit large-diameter reinforcement.

Using a screwdriver with a hook

To speed up the process and make it automated, a modernized screwdriver is used. It is enough to insert a homemade hook into it. A slate nail is suitable for this purpose. It is clamped into the screwdriver and is ready to go.

The principle of its operation is no different from the previous version. The only difference is that the process is significantly accelerated. And if the screwdriver has a speed adjustment, then it is adjusted so that when the wire is stretched to maximum, it does not break.

Tying reinforcement with pliers

This method of knitting is good because it saves wire during the work, due to the fact that you can knit into one, and you don’t have to make loops, as for a crochet hook.

Of the minuses it should be noted:

1. Requires more practice for speed knitting.
2. The knitting speed is 2 times less than that of a hook.
3. When knitting with 2 wires, the result is a rigid knot with a sharp end; you must wear special shoes, otherwise you can pierce your leg.

Source: https://VseoArmature.ru/armirovanie/vyazka-armatury

How and with what to properly knit reinforcement for the foundation

The combination of concrete with reinforcement provides any reinforced concrete structure with strength and durability. In order for the finished metal frame to last a long time and withstand serious loads, you need to know how to knit reinforcement.

Using special knitting wire

To quickly and reliably make the strapping, a special baked steel wire of round section with a diameter of 0.8 to 1.2 mm is used to fasten the reinforcing elements. It bends easily, fits tightly to the joint, and stretches well (that is, it does not tear when knitting).

When working with such material, the knitter does not require any special skills. This method is successfully used both for tying the reinforcement of a reinforced concrete monolithic slab and for the reinforcing frame of any foundation.

How to quickly knit reinforcement, what materials, tools and equipment will be required for this.

Application of hooks

To work with wire, you can use: a manual crochet hook (it can be easily purchased at any hardware store), a homemade hook for tying reinforcement, a semi-automatic mechanical hook (more expensive than a regular manual one) or a crochet hook made using a screwdriver.

How to make a hook for tying reinforcement:

Option #1:

We take a thick electrode or a metal rod of a suitable diameter, sharpen one end of it and bend it at the desired angle. We bend the handle from the second end of the rod (if desired, you can wrap it with electrical tape). The hook for tying reinforcement with your own hands is ready.

Option #2:

The material for production is a metal rod, both ends of which are sharpened. On one end of the rod we place a round wooden blank for the handle (with a drilled hole in diameter slightly smaller than the diameter of the rod); We bend the second end of the rod to the required (convenient) angle.

Option #3:

An old screwdriver (or a construction awl) is suitable as a starting material, the metal end of which is sharpened. Then we bend it to the required angle and get a hook for knitting reinforcement with a comfortable handle.

On a note! The photo will help you easily make hooks for tying reinforcement.

Tying reinforcement with a screwdriver significantly speeds up and facilitates the work. We clamp a hook for wire tying reinforcement, made from a thick nail, into the chuck. By adjusting the rotational force of the screwdriver, you can easily achieve the required joint density. How to knit the reinforcement cage: with homemade tools or purchased ones (or both) - decide for yourself.

How to crochet

The methods of tying reinforcement are quite simple and understandable. Scheme of step-by-step knitting of reinforcement:

1. We cut the wire into pieces (we select the size experimentally depending on the diameter of the rods).
2. Fold the prepared piece in half.
3. We bend the double workpiece around the intersection of the reinforcing bars.
4. Insert the hook into the loop and place the loose ends on it.
5. Rotate the hook (usually 3-4 rotational movements are enough) until a tight twist is obtained.

Attention! You can tie the reinforcement using the above technology using any type of hook.

There is another way to crochet reinforcement - overlapping.

1. We cut a piece of wire twice as long as in the first case.
2. Fold the piece in half and in half again.
3. We place the double bend on the top bar.
4. We place two double pieces under the lower bar and lift it up.
5. We insert the hook into the loop and press the two free ends to it.
6. Rotate the hook and crimp the joint. If we use a mechanical hook, then with force we pull the handle towards ourselves. We obtain a tight twist due to the fact that the translational motion is converted into a rotational motion by means of a worm gear.

Using a knitting gun

A gun for tying reinforcement greatly simplifies the work of creating any reinforcing frame.

Convenience and advantages of use:

• a cassette with knitting wire is inserted inside the device;
• it is supplied automatically;
• the knitting gun is powered by a built-in battery;
• correct knitting of reinforcement with minimal use of manual labor;
• An automatic gun for tying reinforcement allows you to make all twists with the same tension.

But such a convenient and useful device has disadvantages:

• impossibility of carrying out work in hard-to-reach places;
• a gun for tying reinforcement is expensive, so its use is economically justified only when carrying out large volumes of work.

Table with approximate prices for the main models available for sale on the construction market:

Reinforcement model Ø (mm) Unit production time (sec) Number of units from one battery charge Estimated price (RUB)

GS308-6512	6,5÷12	0,8	1000	19000÷21000
GS308-1016	10÷16	0,8	1000	22000÷24000
GS24T	6÷24	0,8	1000	26000÷28000
GS34T	8÷34	0,8	1000	28000÷30000
RT308V	4÷19	0,8	1100	31000÷35000
BM400	10÷29	1,0	2000	44000÷46000
BM200	9÷21	0,85	2000	28000÷30000
KW-0039	10÷22	0,8	1200	47000÷54000
RDL40	12÷32	0,9	3000	43000÷45000
RDL20	9÷21	0,9	3000	41000÷43000
PVA-32	6÷18	1,6	450	44000÷45000

Pliers and pliers

For tying, ordinary pliers, pliers (with slightly blunt cutting edges) and special pliers for tying reinforcement (manual or automatic) are often used.

Knitting reinforcement with pliers and pliers according to production technology is no different from fastening reinforcing bars using hooks. The only difference is that there is no need to form a wire loop.

Strapping using electric welding

Advantages:

1. A fairly reliable way to tie reinforcing bars.
2. High speed of work completion.
3. Less labor-intensive process than hand knitting.

Flaws:

1. Under the influence of high temperature during welding, the physicochemical properties of steel change (the crystalline structure of iron is disrupted). At the joints, the bending and tensile strength of the reinforcing bar is significantly reduced. Ultimately, this leads to a decrease in the reliability of the entire reinforcing frame.
2. The use of welding significantly increases the rigidity of the frame made of reinforcing bars. When compacting the solution with vibrators, there is a risk of deformation or destruction of rigid welded joints.
3. The frame metal in the area of ​​welding seams is more susceptible to corrosion, which reduces the durability of the entire reinforced concrete structure.
4. To carry out welding work, special equipment is required.
5. The site where such work is carried out must be connected to the power supply, which is not always possible (especially during suburban construction).
6. Work can only be carried out by a qualified specialist (welder). How firmly and reliably the frame made from steel reinforcement is knitted depends on his experience and qualifications.

Tying with metal staples

The reinforcement can be tied using special metal staples.

Advantages:

• high speed of connection execution;
• no tool is required for tying reinforcement (everything is done by hand);
• the work can be done even by an untrained person;
• equal density of connected compounds.

Flaws:

• the need to purchase a set of special staples for the production of tying reinforcement of a certain diameter;
• limited area of ​​application: only for fastening simple cross connections;
• insufficient fastening strength (mainly suitable for light horizontal structures, for example for reinforcing screeds).

Tying with plastic clamps

Knitting reinforcement using plastic clamps is a simple and convenient method for creating a reinforcement frame.

Pros:

• plastic is not subject to corrosion;
• ease of installation;
• high knitting speed;
• low cost;
• there is no need to use special tools.

Minuses:

• work cannot be carried out at subzero temperatures (plastic becomes brittle);
• the strength of the connections is questioned by many professionals;
• a fairly large elongation coefficient of plastic can lead to a decrease in the rigidity of the reinforcing frame (or a violation of the geometry).

Some recommendations for knitting the reinforcement cage of the foundation

The rules on how to knit reinforcement for a strip foundation and for a monolithic slab are the same. The length of a standard reinforcing bar is 6 meters. Very often they have to be joined. The overlap of the reinforcement during tying should be 40÷50 cm, the rods should be tied together evenly in 3-4 places.

The same requirements apply when strengthening corners and junctions with L-shaped and U-shaped additional reinforcing elements.

Knitting a metal frame from reinforcement for a strip foundation can be done not only in the formwork, but also in separate fragments (made in a place convenient for you), which are then lowered into a box.

Important! It is necessary to tie the reinforcement of individual fragments together.

The combination of reinforcement for the foundation and the correct choice of its diameter are the main factors influencing the strength of the foundation of the future structure. When tying reinforcement for the foundation, special attention must be paid to the tightness of all connections.

This video will help you understand how to properly knit foundation reinforcement:

In custody

How to tie reinforcement to a foundation or under a floor screed: using a gun for tying reinforcement or a regular homemade hook, the decision is yours and depends on the amount of work and financial capabilities. The main thing is to follow the rules and technology, then the reinforcing frame will be reliable and durable.

Source: https://zamesbetona.ru/armirovanie/kak-vjazat-armaturu.html

Do-it-yourself foundation reinforcement: step-by-step guide

Concrete can withstand bending forces well, but cannot cope with bending on its own. To ensure load-bearing capacity, they reinforce the foundation with their own hands. This applies to a greater extent to strip and slab structures. Metal is placed in piles and pillars more for structural reasons than for real necessity.

Reinforcement rules

Reinforcement of strip foundations and any other is carried out taking into account the following rules:

• for working reinforcement, rods of class not lower than A400 are used;
• It is not recommended to use welding to connect the rods, as it weakens the cross-section;
• It is mandatory to tie a metal frame from reinforcement at the corners; welding is not allowed here;
• Even for clamps, smooth reinforcement is not recommended;
• it is necessary to strictly observe a protective layer of concrete equal to 4 cm, this will protect the metal from corrosion (rust);
• when making frames, the rods are connected in the longitudinal direction with an overlap, which is taken to be equal to at least 20 rod diameters and at least 25 cm;
• if metal is placed frequently, it is worth controlling the size of the aggregate in the concrete: it should not get stuck between the rods.

An example of placing a reinforcing frame
in a strip foundation

A properly prepared reinforcement frame is half the success. It is he who will save the foundation in case of uneven deformations that create bending loads. It is worth considering the issue in more detail using the example of a do-it-yourself strip foundation.

What reinforcement is needed for the structure?

Reinforcement of a strip foundation requires the presence of three groups of rods:

• workers who lay along the belt;
• transverse horizontal;
• transverse vertical.

Transverse reinforcement under a strip foundation is also called clamps. Its main purpose is to connect the working rods into a single whole. Reinforcement of strip foundations is carried out in strict accordance with regulatory documents. What reinforcement is needed for the foundation? To give an accurate answer, complex calculations are performed.

In order not to hire professionals, you can get by with a simplified option. The technology for reinforcing a strip foundation for a small house allows you to assign sections constructively. This is due to the fact that the tape takes up relatively small loads and works primarily in compression.

To make a reinforcing frame, constructive, that is, minimum permissible, section dimensions are used:

• For working reinforcement - 0.1% of the cross-sectional area of ​​the foundation for the house. Moreover, if the side of the tape is 3 meters or less, the minimum acceptable value is taken to be 10 mm. If the side of the building is more than 3 m long, then the diameter of the working reinforcement cannot be less than 12 mm. It is not permitted to use rods with a cross-section larger than 40 mm.
• Horizontal clamps cannot be less than one quarter of the working diameter. For design reasons, a size of 6 mm is prescribed.
• The diameter of the vertical reinforcement depends on the height of the tape for the foundation of the house. For shallow-depth ones, the dimensions of which are 80 cm or less, rods from 6 mm are suitable.

Source: https://DomZastroika.ru/foundation/armirovanie-fundamenta.html

How to properly knit and bend reinforcement for foundations: installation technology

Reinforcement cage indicating strapping locations

In all modern foundations, construction is not complete without the use of reinforcement - interconnected metal rods that absorb tensile stresses when used in conjunction with concrete. The frame creates vertical and horizontal belts, serves to increase the strength of the structure and uniformly distribute loads.

If the reinforcement is weakly or incorrectly connected, it will creep apart, thereby compromising the integrity of the foundation. This will lead to its slow destruction. Tying the rods together is quite simple, but highly specialized specialists know well how to properly knit reinforcement for the foundation.

The frame connection scheme is almost the same for all types of foundations, except for columnar wooden or metal ones, where a frame is formed on top of the pile head using reinforcement or beams.

They are connected to the head and welded, in which case the rods or wire rod have to be bent at a specific angle.

Three methods of tying reinforcement cages

Schematic representation of reinforcement tying technology methods

To form the metal frame of the base, three strapping methods are used:

1. Welding. At first glance, welding is the simplest and most effective way to connect reinforcement, but in practice everything looks different. During welding, the metal is heated to high temperatures and deformed, which results in a partial loss of rigidity. You also have to hire a professional welder who knows about the properties of the metal and can avoid burning it, and this is an additional financial expense. There is also a risk of destruction of the welding site during operation of the industrial vibrator. Difficulties arise if you bend metal close to the welding site.
2. Connection using bent wire or plastic clamps (ties). This method is popular among many developers, since the connection can be made with your own hands in a matter of minutes. If flexible wire is used, then a special tool must be used to connect the links. Plastic clamps are more reliable than wire, but are more expensive. The connection diagram is similar, only then you have to bend the rods at the required angle.
3. Overlapping. This method involves overlapping reinforcement with further fixation with wire. It is practiced more for horizontal belts made of mesh, and a vertical smooth rod is used inside the joint.

Any of the above methods can be implemented with your own hands. In this case, you have to bend the metal, which is quite problematic, given the rigidity of the reinforcement and its minimum diameter for horizontal chords of 12 mm.

Knitting reinforcement with your own hands

With all the variety of specialized construction tools, not all private developers have the opportunity to buy or rent them. Knitting rods does not require expensive tools; moreover, you can do it yourself.

To do this, you need to purchase steel binding wire. It is quite flexible and durable, has a diameter of 2-3 mm. To bend it, you will have to use pliers or a specially made hook, which subsequently twists around the reinforcement and fixes it. Some craftsmen who perform reinforcement with their own hands sometimes use a screwdriver as a simpler and easier way to knit. If you knit with wire, you will need:

• One of the options for knitting the base frame using a hook. Craftsmen sometimes use a screwdriver as an easier way to tie reinforcement bars with their own hands. Cut a piece of wire about 30 cm long. You can do more if you don’t mind it, but the ends will get in the way (including excess waste);
• then fold the wire in half to increase rigidity and strength;
• bend it diagonally around the reinforcement joint and make a small loop;
• Place the hook in the loop and twist clockwise evenly, without unnecessary effort, until it becomes difficult to wrap or the connection becomes strong enough. The main thing is not to use force, since it is easy to break the wire and then you will have to start all over again;
• Cut off the ends of the wire with pliers and discard.

In the case of reinforcement of a columnar foundation, the reinforcement cage can be bent and then fixed to the heads with special clamps. Some manufacturers already supply metal or wooden piles with special clamping brackets and couplings.

In this case, it is enough to bend the rod and insert it into the bracket. Clamp the bracket and boil it on top; you can do all this yourself, using a minimum of tools.

In the case of using smooth reinforcement, the tying process is more labor-intensive, since the hooks will constantly bend and cannot be done without a specialized tool at hand, as well as without outside help.

It is better to knit the reinforcement cage for a slab monolithic foundation from several belts. For the horizontal tier, spiral rods with a cross-section of up to 16 mm are used, and for vertical links, smooth rods with a cross-section of up to 10 mm are used. When installing the lower mesh, it is recommended to use plastic expansion joints, which will create a uniform pitch. Then, when knitting vertical rods, it is important not to forget to take them outside the foundation, due to the fact that load-bearing walls will be connected to them.

Using plastic ties for knitting is a more expensive option for replacing wire, but clamps (ties) can be found in any household. The principle of tying is similar, but the plastic for the ties is less durable. Therefore, it is better not to use force during installation.

The most popular clamps have a special core at the end of the tie; they are used to secure cables and pipes to vertical surfaces. Plastic showed excellent results when knitting with your own hands in warm weather; in cold weather it quickly loses its elasticity and bursts.

matings:

Tying reinforcement for the foundation according to all the rules

Sketch of the technology for correctly creating connections between reinforcing bars and crocheting

It is quite possible to knit reinforcement using available materials. But it is worth noting that correctly tying the rods together does not guarantee compliance with all building codes and high-quality installation. Since the pattern of knitting the frame depends on the type of foundation, its size, thickness and type of material used. Therefore, you need to take into account several key rules:

1. If mesh is used as a reinforcement frame, then the strapping must be overlapped.
2. Taking into account the type and cross-section of the reinforcement, it is necessary to calculate the length of the bypass at the connection points.
3. The rods must be bent strictly at a certain angle and evenly.
4. The grade of concrete and working conditions at the joint are taken into account. The minimum overlap length is at least 25 cm.

If reinforcement is carried out at a height of 3 meters or more, then scaffolding or scaffolding is indispensable. The strapping technology turns out to be more complex, due to existing safety rules for working at height. Tying is carried out in three stages:

1. First prepare the reinforcement and tie slings to it.
2. Raise to the required height, level and place in plastic guides.
3. Tie the rods using any of the listed technologies.

Work at height should be carried out only with several workers at a time, provide insurance and control the process of lifting the rods and then installing them in the specified places. Doing this yourself without insurance is strictly prohibited.

The cost of strapping is relatively low, since craftsmen can process several square meters of frame in an hour. And when using special knitting tools, it’s even faster. And they guarantee the quality of the knitting of the rods and compliance with all construction standards, especially since the rods will be bent with special pliers.

instructions

Source: https://FundamentClub.ru/armirovanie/kak-pravilno-vyazat-armaturu.html

How to knit reinforcement correctly - ProBuildingmaterials

Construction of a house begins with laying the foundation. The main requirement for a concrete foundation is its strength. It is achieved by laying a frame of reinforcement bars tied together inside the concrete. Such a frame is called reinforcing. This article will discuss such an important stage of construction work as tying reinforcement for the foundation.

Methods

It is necessary to first consider what methods of tying reinforcement for the foundation generally exist. They differ from each other by type:

• tool;
• material;
• knitting patterns;
• type of fittings.

By type of tool - this can be either knitting reinforcement for the foundation manually or using a special tool. For the latter, special crochet hooks, screwdrivers, and special pistols , produced specifically for this operation.

The material used to connect reinforcement bars to each other is:

• tying wire is the most common and reliable technology for tying reinforcement for the foundation, because it is performed with tying a knot.
• paper clips - are wire clamps, which, unlike ligation with knitting wire, are made without tying a knot.
• small clamps made of plastic - this new material has become widespread due to its ease of installation and high knitting speed, and besides, it is not afraid of corrosion. However, such a bundle of reinforcement for the foundation causes a certain skepticism among professionals. Read more here.
• clips - made in the form of latches that fix adjacent rods to each other.
• welded connection - this old method has not become widespread, since the welded connection, due to its fragility, is susceptible to cracking during concrete pouring and does not have the necessary reliability. To perform a high-quality welded joint, you need a highly qualified welder.

Required wire

When choosing wire, the following factors must be considered:

• Manufacturing accuracy class. The accuracy class is determined by the production method. There is a wire of a higher accuracy class, its deviation of the actual size, diameter, from that declared by the manufacturer along the entire length of the wire is less than that of a wire of a lower accuracy class. However, for knitting reinforcement, the accuracy class is not particularly important.
• Wire rolling method. There are two types of rolled products: cold-rolled and hot-rolled. Cold-rolled steel is rolled out from blanks by presses without heating. With the hot rolling method, rolled steel is rolled out in a heated state, which gives greater strength.
• Which group in terms of tensile strength does the wire belong to (there are the first and second groups);
• Degree of corrosion resistance. On this basis, there is only one difference - whether there is a galvanized coating on the wire or not.

The criterion for choosing a wire is very simple, you need a wire that is called “knitting” . It has a full set of necessary characteristics: sufficient softness with the declared strength, abrasion resistance and reliability when fastened.

Galvanized wire is considered overkill.
The optimal diameter of the knitting wire is 1.2-1.4 mm. A wire with a diameter of 1.6-2 mm takes a lot of force, as a result of which construction slows down, and the piece is too weak, it will simply burst.

You need to check the rigidity of the connection of the reinforcement by touching the rods - if they are rigidly fixed, they will not move, which means everything is in order. You should not test the strength of the knot itself, otherwise there is a risk of loosening the binding.

The length of wire recommended for one knitting point is from 30 to 50 cm. The wire itself is extremely cheap - about 50 rubles. for 100 meters. To avoid running out of it at the wrong time due to loss or excessive consumption, it is recommended to buy it with a double supply. 100 rubles for 200 meters is quite inexpensive.

How to bend reinforcement correctly, all the ways

You should choose how to bend the reinforcement for the foundation based on its diameter: with your own hands is quite easy, but for thicker reinforcement you will have to use special devices, homemade or specialized.

Among homemade devices, two methods are common. The first is when an ordinary pipe of suitable diameter is installed vertically and its base is poured with concrete so that it stands firmly.

The fittings are inserted inside all the way, and now the end protruding from the pipe can be bent by simply leaning on it. If this presents certain difficulties, then a second pipe is additionally put on the free end of the reinforcement, and now, due to the increased leverage, the thick reinforcement can be easily bent.

Welding is also often used. By softening a section of the rod with heat, it becomes easy to bend. The same is done with a blowtorch and a hammer. After heating the bend point with a lamp, bend the reinforcement with a hammer.

The most radical way is to make a cut with a small grinder and then bend it completely using available tools.

Crochet

The design of the hook for these purposes may be different, but this is not so important. The meaning lies in the presence of a hook as such, because it is used to thread the wire. The rules for tying reinforcement for the foundation are shown schematically in the figure.

Pay attention to the sequence of actions:

1. Bend the wire in half;
2. Follow the arrow, as in the figure, bring it into position for threading;
3. Insert the hook into the loop that will now be wound;
4. Place the hook loop inward between the free ends of the wire;
5. Without removing the hook, twist until tightened, but do not pinch;
6. Ready!

For strip foundation

The strip foundation reinforcement has two patterns for laying rods:

• system of 4 rods : two at the base of the foundation, two at the top (used if the width of the foundation does not exceed 50 cm),
• system of 6 rods : an additional longitudinal rod is placed between the two main ones (used in cases where the foundation width is more than 50 cm).

Bent reinforcement is laid at the corners, and the ends should protrude from the corner by at least 40 cm. The reinforcement connection nodes should be located from each other at a distance of no more than 60 bar diameters .
For example, if 12 mm reinforcement is used, then the strapping should be every 72 cm or more often. How to choose reinforcement for a strip foundation?

For columnar

This is a foundation that is placed on pillars that act as piles.
Bound reinforcement for the foundation is placed inside the pillars before pouring. The tying of reinforcement for a columnar foundation is the same as for a strip foundation - either 4 rods, or 6 for large columnar foundations.

For vertical rods in this type of foundation, 12 mm reinforcement is used, since this is a vertical foundation. The cross rods can be thinner and smoother.

For wooden houses, it is allowed to use longitudinal and vertical reinforcement thinner than 12 mm. Sometimes, for the foundation of small wooden buildings, a welded frame is constructed from vertical rods connected with hoops like a barrel. This is incorrect, because with this bonding method you can only use welding, and this is not a completely reliable method. We have already talked about this above.

For slab

A reinforcement frame for a foundation can take the form of a two-dimensional plane, a mesh formed from reinforcement bars. The second option is volumetric, in the form of two meshes of intersecting reinforcement, located one above the other and connected by transverse rods.

Reinforcement - from 12 mm and above, up to 16 in private housing construction. The mesh cell size is 200x200 mm. The distance from the lower reinforcement belt to the pillow (or insulation) is 50 mm. The top belt is also protected from external influences by a 50 mm layer of concrete.

Cost calculation (price for work and materials)

Let's take as an example a strip foundation 10 by 10 meters. This is the perimeter of the house. In addition, there will be a foundation for internal load-bearing walls - two walls of 10 meters each. It turns out 60 m.p. foundation.

How much reinforcement and tying wire will be required with the right approach?
Let's say the foundation is less than 50 cm wide - it will use a scheme with four longitudinal rods. In this case, in 1 linear meter of the foundation the following will be used:

• 4 longitudinal rods. That means at 60 mp. will be 240 meters.
• 4 vertical. With a foundation height of, say, 50 cm, their height will be no more than 45 cm. 4 x 45 cm = 1.8 m. In 60 meters of the foundation - 108 m.
• 4 transverse. With a foundation width of 45 cm, the width of the transverse ones will not exceed 35 cm. 4 x 35 cm = 1.40 m. In 60 meters of the foundation - 84 m.

How much is it?

For longitudinal rods we use 12 mm reinforcement costing 25-30 r/m.p.
240 x 35(30) =6000 (7200) For vertical and transverse rods, take 6-8 mm costing 12-16 r/m.p. (108+84) x 12(16)=2304 (3072)

So, the purchase of reinforcing rods for this foundation will cost from 8304 to 10072 rubles.

Now let's calculate the required amount of wire. 4 ties for a 4-bar foundation per 1 m.p. This, based on a maximum consumption of 50 cm per tie, is 2 meters of wire per meter of structure.

We have 60 meters, so we need 120 meters of wire. 1 m of wire with a diameter of 1.2 mm weighs 9 grams, respectively, 120 m of wire with a diameter of 1.2 mm weighs about 1 kg, which costs about 50 rubles.

The wire is cheap, so you can and should buy it with a double supply - 240 meters for 100 rubles.

All that remains is to calculate the cost of installation and tying of the frame. As a rule, it is not calculated separately and is included in the total cost of pouring the foundation. In the regions, such work is cheaper, but the price range is approximately the same - 1000-2000 rubles per cubic meter. This price includes the construction of a trench, installation of formwork, binding of the frame, pouring concrete and removing the formwork.

The total length of the foundation we are calculating is 60 meters, width 0.4 m, height 0.5 m. Let's calculate the volume: 60 x 0.4 x 0.5 = 12 m3. With this volume, the cost of foundation work will be 12,000 - 24,000 rubles.

Source: https://isss.ru/raznoe/kak-pravilno-vyazat-armaturu.html

How to knit reinforcement for beginners: methods, norms and rules, frame for the foundation

There are only two ways to attach reinforcement to a frame: electric welding and knitting. We will not open a debate about which one is preferable. Let’s just say that knitting does not reduce the strength of the working rods.

Any welding weakens the metal because it creates local stresses in it. This negatively affects the reliability of the entire structure.

Compared to welding, knitting work is more labor-intensive.

Despite this, in private construction with its small volumes it is better to choose them. Especially when it comes to such critical structures as foundations and floor slabs.

articles:

In this article we will tell novice builders how to knit reinforcement correctly. Let's look at the tools, materials and technologies used for this work. We hope that the information received will help you confidently handle metal, assembling strong and reliable frames.

Crochet technology

There is nothing complicated in this operation. After doing it several times, you will quickly get used to it.

The essence of the method is as follows: the intersection of the rods is covered with steel wire folded in half. The crochet hook is inserted into the loop and the other free end is grabbed with it. After this, the tool is rotated until it is tightened. The ends of the wire are bent inside the frame.

The craftsmen know one little secret that guarantees tight contact: after not tightening the loop a little, you need to pull it towards yourself and only then tighten it to the end.

Scheme for knitting reinforcement using a hook

Working with a screwdriver is not fundamentally different from crocheting. The advantage is higher speed and less labor intensity. When using a screwdriver, do not forget to set the rotation speed of its chuck to minimum.

You should not knit reinforcement with an electric drill. The large inertia of this tool does not allow you to accurately determine the moment of completion of tightening.

Methods for connecting steel rods and the main types of nodes are shown in the diagram below.

Materials

To assemble the frame, special annealed wire is used. It is durable, but at the same time quite soft. This allows you to tighten the knots without the risk of tearing it. The recommended diameter of this material depends on the cross-section of the reinforcing bars and ranges from 1.0 to 1.4 mm.

Cheap wire comes without coating and is called black. It is more resistant to corrosion and has a protective layer of zinc.

Knitting wire is produced in two versions: in coils and measured (in segments). Working with a skein is more difficult because it has to be cut into pieces by hand. The measuring material can be used immediately. Wire with loops at the ends is especially convenient.

Norms and rules for performing work

Guidelines for the design and manufacture of reinforcement cages are contained in two regulatory documents. GOST 10922-2012 specifies technical conditions for knitted and welded connections of reinforced concrete structures. The set of rules SP 52-101-2003 regulates the requirements for the design of frames.

Based on these standards, standard patterns for tying reinforcement under a strip foundation, dimensions of overlaps, diameters of the reinforcement used and other rules for the execution of work have been developed.

When joining rods on straight and corner sections, the length of the overlaps is important. SNiP sets this parameter depending on the diameter of the working fittings (in millimeters):

• 300 mm for rods with a diameter of 10 mm;
• 380 for 12 mm;
• 480 for 16 mm;
• 580 for 18 mm;
• 680 for 22 mm;
• 760 for 25 mm.

Knitting the strip foundation frame

The estimated number of longitudinal rods (diameter 12-18 mm) are placed at the bottom of the trench on supports (bosses) 4-5 cm thick. The distance between them depends on the size of the foundation and can range from 5 to 20 cm. If the standard length of one steel rod (6 meters) is not enough for the entire “ribbon,” then several rods are used. They are connected to each other, observing the regulatory overlap.

Supports for reinforcement cage

Clamps made of smooth or corrugated steel with a diameter of 8-10 mm are attached vertically to the working rods. According to building codes, the pitch of the clamps must be at least 3/8 of the height of the foundation (20-50 cm).

Having installed the clamps, the upper chord of the working reinforcement is attached to them with wire, observing the design distance between the rods.

At corners and junctions, clamps are placed more often (1/2 step), and the working reinforcement is bent, connecting to the rods of the intersecting section of the “ribbon”.

The length of the bend must be at least 50 diameters of the working reinforcement.

Making a reinforcement cage in a trench is labor-intensive and inconvenient work. That's why experienced builders use this simple device.

Having laid the longitudinal whips on wooden stands, clamps and the lower belt of the working rods are tied to them. The finished structure is transferred and placed in a trench.

Assembly of the reinforcement frame of a monolithic slab is simpler than that of a strip foundation. The design here consists of two flat meshes. The lower rods are laid perpendicularly with a given pitch and connected to each other. Then, at the points of their intersections, stands made of steel rods are placed and the upper mesh is screwed to them.

Stand for mounting the upper frame of a monolithic slab

In recent years, fiberglass reinforcement has begun to be used to assemble frames.

You can knit it in several ways:

• annealed steel wire;
• plastic zip ties;
• plastic clips.

Approximate prices

The cost of tying reinforcement, as estimators say, “sits” in the total price of 1m3 of reinforced concrete. In square or linear meters it is calculated individually for each type of structure. In this case, it is necessary to take into account various parameters (the width and height of the grillage, the thickness of the slab, the cross-section of the reinforcement, the level of complexity of the frame, etc.).

For approximate calculations, builders use prices in rubles per 1 ton of metal used. Today in 2017 it averages from 20 thousand rubles.

Source: https://greensector.ru/stroitelstvo-i-remont/kak-vyazat-armaturu-dlya-nachinayushhikh-sposoby-normy-i-pravila-karkas-pod-fundament.html

How to properly tie foundation reinforcement, necessary tools - Machine

Many people believe that only welding can secure reinforcement in the most rigid way. Everything is true and false : the fact is that the main task pursued when connecting reinforcing bars is not to impart strength to the resulting frame. It is achieved during pouring using a concrete mixture.

• The point of this operation is to fix the metal rods in the desired position and prevent their displacement relative to each other during pouring or subsequent vibration and during operation.
• Welding will cope with this task, but:

• will change the crystalline structure of the metal of the rods at the joints and reduce its strength;
• will create an overly rigid structure, which may break during vibration and subsequent operation precisely because of its rigidity;
• will require special equipment and knowledge;
• will increase the time and cost of construction.

Currently, welding of reinforcement is used exclusively in industrial construction for a limited type of objects that will stand on ground that is not prone to subsidence.

Most home craftsmen prefer knitting.

This connection method is free from all of the above disadvantages, is simple, reliable, and does not require any special knowledge or the use of expensive equipment.

In addition, when tying reinforcement for the foundation, the integrity of the metal is not compromised, and the rods themselves retain limited mobility relative to each other, which allows them to withstand vibration and loads arising during operation without any harm to themselves.

What you need to knit reinforcement

First of all - steel wire. You can use white, galvanized, but regular black will do. There is no need to be afraid that it will collapse due to rust: if the reinforcement is laid correctly, that is, with a fairly large layer of concrete (at least 2 cm), the access of oxygen to the reinforcement elements is completely eliminated, and there will be no corrosion.

The following requirements apply to the knitting wire:

1. Cross-section from 1.2 mm to 1.6 mm (thinner wire will not be able to provide a reliable connection, and working with wire of larger diameter is very difficult).
2. The ability to bend easily and not break when twisted.
3. It is recommended to purchase wire made from low-carbon, baked steel.

As for the length of the sections into which the wire is to be cut, on average it is 20 cm. The exact value of this parameter depends on the method of connecting the reinforcement, its thickness and the experience of the craftsman.

To save money, you can use metal cords from truck tires; for this you will have to burn them.

Sometimes imported tires use plastic cord. This is easy to determine: just make a cut on the inner side facing the rim. If the knife hits the metal, everything is fine.

Those who don’t really like the process of burning tires can buy a coil of wire in the store, as well as the necessary tools.

1. There is a special hook for knitting, which you can buy in a store or make yourself.
2. This method, which is called a double-row knot, is simple because it requires minimal effort. The necessary actions are as follows:

1. The wire is bent in half and the tip of the resulting loop is slightly bent - this is necessary to make it easier to slip it under the reinforcement.
2. The loop is slipped under the rods diagonally, and its end is grabbed with a hook.
3. The free end of the wire is placed under the tip of the hook, the hook is twisted and twists the wire.

You can slightly change the procedure by applying in practice knitting reinforcement using method No. 2:

1. Make a wire loop by bending the wire.
2. Place the wire on the rods and press it with your finger.
3. Place the free ends under the rod diagonally and bend them towards you.
4. Insert the hook into the loop and twist the wire.

Method number 3:

1. The wire loop is inserted under the reinforcement from below.
2. The loop is grabbed by the hook, and the “tail” from the free ends is bent through it at a right angle.
3. You need to twist the hook.

Method number 4:

1. Again, a loop is made from the wire and threaded from below under the reinforcement.
2. The end of the wire loop is caught with a hook.
3. The tail formed from the free ends is bent over the hook and lowered so that another loop is formed.
4. You will need to twist the hook.

The last method is good because at the twisting stage it frees up your left hand, and you can use it to hold the rod. Otherwise, all four methods differ only in whether the free end of the wire is brought to the hook or vice versa, and in what is wrapped around what.

There is no fundamental difference between them: you choose the one that is more convenient, but it is worth remembering some points:

1. It is important to correctly determine the size of the loop that the hook will hook into and not make it too long. Otherwise, to tighten the wire, you will have to rotate the hook 7-8 turns, and the wire may break. The optimal number of revolutions is 3 or 4.
2. When crocheting, you need to lightly tighten the loop, but do not overdo it. Uneven tension of knots in different areas is not dangerous if it does not lead to a change in the position of the rods, but it is desirable that all knots be tightened with equal force. This will be easier to do if you use pieces of wire of the same length and tighten the knots with the same number of turns of the hook.
3. For large volumes of work, experts recommend not cutting the wire, gradually unwinding it, but cutting the entire coil at once using a grinder, then taking several rods (they will all be the same size) and bending them in half. It is easier to work with such blanks.

The remaining ends can be left, bent down or cut off. It is important that after pouring they are covered with a layer of concrete mixture at least 2 cm thick.

Additional tools

Most craftsmen also knit corner reinforcement elements with a double-row knot, although for this there is a special type of knot made with pliers.

There are other knots for tying reinforcement. But they are difficult to implement and are rarely used.

These are the cross and dead knots.

If you have a welding machine at your disposal, you can make your own original tool from a hollow steel tube with a cross-section of 1.2 cm and a drill 20 cm long, which fits freely into the tube. You will also need 2 8 mm bolts, 2 corresponding nuts and a hook made of wire with a cross-section of 6 or 8 mm.

At the end of the tube, 2 holes with a diameter of 8 mm are drilled, nuts are welded to them and bolts are screwed in. The drill is inserted into the tube, after which the bolts are tightened so that their ends fit into the drill flange.

A hook is welded to the end of the drill, and a finished tool is obtained.

Now all that remains is to pull the tube, the drill will begin to rotate and twist the wire.

If you want to fully automate the knitting process, you can use a screwdriver with a hook attached to it. Just be sure to set its speed to minimum. It is not recommended for an inexperienced craftsman to use a drill for this purpose due to its high rotation speed.

There are knitting guns that can reduce human participation to a minimum and reduce the time required to complete the work. The gun is powered by an electric motor, which pulls the wire wound on a bobbin located in the housing.

This is a fairly expensive tool, so its purchase is only advisable if viscous reinforcement is done professionally. Another disadvantage of the gun is the short battery life and the fact that it cannot be used in hard-to-reach places, as well as for tying corner elements.

Other methods of tying reinforcement

When creating a foundation for small objects, composite reinforcement is sometimes used, which can be knitted using plastic clamps.

Among the advantages are the ease of performing the work, their absolute safety, and minimal risk of corrosion. Among the disadvantages, it should be mentioned that walking on reinforcement connected in this way is strictly prohibited. Plastic clamps cannot be used at sub-zero temperatures.

Another way to knit composite reinforcement is with clips made of heavy-duty plastic. The knitting technology is extremely simple: the rod is pressed into the gap of the clip until it clicks. But it is impossible to correct the mistake made and remove an incorrectly installed rod without damaging the clip.

Plastic fasteners are not used for metal fittings.

Safety precautions when tying reinforcement

To minimize the risk of injury, the following simple rules should be followed when working with rebar and tying wire:

1. When cutting rods or wire with a grinder, be sure to wear safety glasses or a mask that will protect your face from sparks and small metal fragments.
2. To avoid damaging your hands, work with the knitting wire only in thick gloves. It is advisable to use clothing that covers the body as much as possible.
3. When moving near the reinforcement frame, do not lean on the bars.
4. Do not walk on or stand on the rods. When working with a large area of ​​reinforcement frame (for example, under a floating foundation of a house), use wooden walkways placed on top of the reinforcement for movement. There should be no foreign objects on the walkways.

Despite its apparent simplicity, this work requires skill, and at first mistakes cannot be avoided. It is better to purchase wire with a reserve and, before starting knitting, practice a little on a piece of reinforcement. The training will take some time, but the experience gained will help you subsequently create an impeccable reinforcement frame.

Source: https://regionvtormet.ru/okrashivanie/kak-pravilno-svyazat-armaturu-dlya-fundamenta-neobhodimye-instrumenty.html

How to knit reinforcement - a detailed description of patterns and methods

In construction, reinforcement is the name given to interconnected elements that, when worked together with concrete, create a more advanced material – reinforced concrete. Thanks to reinforcement, beams and slabs better withstand tensile stresses, and compressed structures increase strength. To obtain the desired effect, the reinforcement fragments are connected to each other. Due to the method of connection, the method is called binding.

How to knit reinforcement

Since reinforcement in the form of steel rods is mainly used in the construction of foundations and main walls, their connection to absorb compressive or tensile stresses is mandatory. In mass construction, the welding and tying method is used for connections, in individual construction, usually only tying. In this case, the reinforcement is knitted using:

• knitting wire;
• reinforcement clamps.

The term “knitting wire” means round wire made of low-carbon steel in accordance with GOST 3282-74. It can be regular or heat-treated (marked “O”), coated or uncoated. The thickness of the zinc coating determines the class of the material.

When choosing which wire to knit the reinforcement with, you should pay attention to the grade of concrete and the operating conditions of the structure. In this case, mechanical properties are taken into account.

So, if tying reinforcement for the foundation is supposed to be done manually, it is better to choose a thinner option, since without a special tool, thick wire for tying reinforcement requires significant effort.

In addition to industrially produced low-carbon wire, it is permissible to use metal cord from car tires. When tires are burned, the metal cord is released and simultaneously undergoes heat treatment, which makes it easier to work with in the future. This option of knitting material is acceptable only for small volumes of work and individual low-responsibility construction.

Plastic clamps, regular and with a steel core, are also applicable. They are usually used for fiberglass reinforcement.

The use of clamps is permissible in cases where liquid concrete will not be subjected to mechanical loads during the hardening process (they will not walk on it, stack heavy things, or load it with other building materials).

This option is applicable for low-rise buildings, since during the process of pouring a large mass of concrete mixture, the fastenings can move along with the reinforcement. The displacement disrupts the functioning of the frame and leads to a change in the design strength of the structure.

How to knit reinforcement for a foundation

Depending on the chosen material for knitting, various fixation methods are used. The simplest situation is with plastic clamps. They are wrapped around the joint as far as the length allows and tightened.

To correctly knit reinforcement for a strip foundation, you will need a tool. Depending on the reinforcement tying pattern, the rods are distributed over the future pouring field.

If you plan to create a foundation, some of the rods are stuck into the prepared base (rammed sand and gravel backfill), this makes the work easier. After completing the connecting work, the frame is raised above the ground on special stands. This is necessary to prevent corrosion of metal elements protruding from the concrete. To connect the rods use:

1. special pliers for tying reinforcement; 
2. crochet hook, homemade or industrial production; 
3. a curved hook made of a thick nail or dowel, inserted into the chuck of a drill (screwdriver). Thanks to this mechanized hook, wire twisting is done faster and with less manual force.  
4. semi-automatic hook for tying reinforcement. A mechanism with a leg and a spring return mechanism pulls the wire and makes several rotational movements. This happens thanks to the spiral grooves on the hook leg, which, when pulled back, provide rotation and return to its previous position.  

The use of such tools is advisable for small amounts of work, for example, when building your own house, where tying reinforcement with your own hands is done over a short period of time (when preparing the foundation for a frame or brick structure or installing a fence on a concrete base).

A do-it-yourself hook for tying reinforcement is made from a used electrode, nail or other suitable metal rod of the required strength.

Professional tool for tying reinforcement

When creating a large volume of reinforcement for reinforced concrete structures (professional activities, large private construction), instead of manual or semi-automatic tools, it is better to use an automatic, so-called gun for tying reinforcement. This useful device was invented in Japan; it allows you to tighten the wire at the connection of the rods with the required force in a matter of seconds.

The operating principle of the device is shown in the video.

Source: https://stroy-okey.ru/house/foundation/kak-vjazat-armaturu-podrobnoe-opisanie-shem-i-sposobov/

How to knit reinforcement

Hello, dear readers! Our interview will be devoted to an unusual job that, despite its simplicity, many are afraid to do themselves, namely how to knit reinforcement correctly . Today, the veil of secrecy of this matter will be lifted for us by a young, but despite this very experienced, foreman Nikolai Nikolaevich, who has built many objects.

Hello, Nikolai Nikolaevich. We have a number of questions for you, perhaps they sound simple and unprofessional, but we are not yet familiar with the correct names and terminology.

— Good evening, dear readers! I will try to answer all your questions as clearly and completely as possible. So, let's begin.

Why is reinforcement knitted in most cases rather than welded? Is the connection of reinforcement by welding different from a mechanical connection?

— Reinforcement, in most cases, is knitted, not welded. Because during a welded connection, the composition of the steel changes, resulting in weak spots in the reinforcement bars. Another disadvantage of a welded joint is the completion time, in comparison with the so-called mechanical method (actually, viscous).

Also, a lot depends on the experience of the welder, and if he is “green”, then in most cases the structure will not be able to fulfill its main purpose - to withstand the load.

However, welded joints are often used in the construction of panel buildings, due to the fact that the construction of such houses mainly uses complex teams (installers, welders, carpenters, concrete workers) and it is not economically profitable to take a separate specialty, reinforcement workers.

As for knitting, this is a simple and fairly quick way to attach reinforcement that does not require special skills; this method is most often found in monolithic construction. Knitting performs the same function as a welded joint, only with the help of a knitting wire. In any case, both welding and bonding should perform the same function. The main thing is that when pouring the reinforcement frame with concrete, the reinforcing bars do not change their position and shape. They do not impart strength to the product - strength is ensured due to the integrity of the structure poured with concrete.

What are the necessary tools and materials for knitting?

— Wire is the most important element when performing knitting work, since the quality of the assembly and specifically the fixation of the reinforcement, and, consequently, the final product, depends on the quality of the wire . When knitting, burnt wire with a diameter of 1 mm, always of round cross-section, is usually used.

The difference between baked and unburnt wire is that the first bends well, fits tightly to the reinforcement and has the property of ductility (i.e. it does not break when knitting), unlike the second, untreated, which bends hard and often breaks and breaks when tying a knot. . If they bring it unfired, then don’t even try to use it, since it is virtually impossible to knit with it.

Also, for tying reinforcement (mechanical fastening), you need a hook , or collets, and plastic bosses (fasteners).

Ordinary hook

Automatic hook

Knitting gun

Boss (retainer)

— This is a plastic part that is placed between the reinforcement and the formwork to create a protective layer. Without them, the reinforcement may touch the formwork and, after pouring, will stick out from the concrete and, accordingly, rust, lose strength and destroy the structure.

Please tell us about each tool - describe its advantages, disadvantages, when should it be used (a simple hook, a homemade hook, a screw hook, a gun)?

-As for each tool individually, it’s up to everyone to determine who is used to working with what. The most common tool is a hook or collet. The gun is good on horizontal surfaces where you don’t have to crawl into hard-to-reach places. The advantage of a pistol is the speed of work.

The disadvantage is that they are extremely inconvenient for knitting in hard-to-reach places, the battery also drains quickly and wire consumption is higher. Speaking of hooks, the most popular is the homemade hook . If you decide to get serious about tying, then it’s better to make a hook for tying reinforcement yourself. It is made from corrugated reinforcement, and a bearing is installed in the handle to facilitate rotation.

A magazine hook is only good for training, as they are usually short and quickly rust, which makes a terrible sound and reduces the speed of work. There are semi-automatic (screw) hooks , but I don’t like working with them: there are pieces of wire tails left, then technical supervision comes and forces you to redo all the debris in the ceiling.

And he’s doing the right thing, because maybe you’ve noticed rusty stripes appearing on the surface of the ceiling on your or your friends’ ceilings? This is nothing more than wire or hackwork by a craftsman who, when creating a protective layer, did not put bosses under the frame when pouring concrete into the reinforcement.

Does the knitting method differ depending on the part of the house - wall, foundation, ceiling?

— In theory, there are many ways of knitting, but in practice the two main ones are one loop for an overlap connection and 2 loops for a butt connection. Almost everything is knitted with one loop, even the corner elements, although in theory, the corner elements are knitted with a different knot. The loop is good for its simplicity and reliability - you can learn it in literally five minutes, and it’s hard to make a mistake.

How long does it take to knit reinforcement?

— I haven’t heard of such a norm, everything is according to ability. Also, the speed of knitting greatly depends on the design: knitting an overlap is much faster than an arch with curved elements.

Is there a certain standard for wire consumption?

— As such, there is no standard for one unit; there is an expense for the design. This norm is calculated in the project documentation for the facility, based on the fact that one knot requires 20 cm of wire if crocheted, and if with a pistol, then the consumption will be greater. It is very difficult to calculate the consumption, for example, for a wall or ceiling separately, since some of the knots will break and will need to be bandaged, and a lot depends on the craftsman.

Manufacturers of knitting guns claim that with this device all knots will be tightened with the same force! How important is it to tighten the knots with the same force?

— What is important for us is not the same clamping force of the rods, but that they do not change position and the structure itself does not change when pouring the form with concrete, since if changed, the protective layer will be of the wrong thickness and, in the future, cracks and rust will appear on the concrete.

In general, the same tightening force of knots is nothing more than an advertising ploy by pistol manufacturers, because it is not so important.

But all the same, when we crochet, you shouldn’t deliberately “squint” and tighten with deliberately different forces - such experiments can cost you dearly, so we tighten more or less evenly and everything will be fine.

What will be the strength of the structure if it is connected incorrectly, with insufficient force, or in this case the connection will burst altogether?

— If one connection breaks, it’s okay. I repeat - the most important thing for us is that the structure does not change shape when poured. But still, the correct knitting of reinforcement will determine the strength of the structure.

What other methods of fastening reinforcement do you know?

— I heard about two more methods - metal clips and tying reinforcement with plastic clamps. Unfortunately, I didn’t work with them, and I didn’t hear anything like that from my friends. Apparently, these methods are not widely used for some reason. I myself am a follower of the “classics”: I knit with an ordinary crochet, as it is simple and fast and I don’t use all these newfangled innovations such as screw hooks, paper clips and guns.

Thank you, Nikolai Nikolaevich, for your story about this work.

- Please! Contact me, I will always be happy to answer any of your questions.

Source: https://vseostroyke.by/kak-pravitno-vyazat-armaturu/