How to attach an anchor bolt: video, photos, nuances, tips

If you need to secure or hang something heavy and massive, then it’s impossible to think of a better option than an anchor bolt. Have you seen all those fiber optic wires running between buildings? They are quite heavy. It is the anchors that hold this entire web.

An anchor bolt is optimal under two conditions. Firstly, if you plan to hang a heavy load. Secondly, the material of the attachment point is dense and hard. Yes, such fasteners are not suitable for fragile surfaces. Its main area of ​​application is concrete, natural stone and solid brick. In our article we will talk in detail about the types of popular anchor bolts, define their purpose, installation methods and design.

There are enough types of anchor bolts to surprise the average person. This is quite fair. Each fastener was created for a specific type of cargo and the nuances of its fastening. There are even hardware that are only used for certain things. Let's look at the most basic ones.

Anchor fastening types and features of anchors application tightening technique

Using a kit for fastening to anchor supports, it is possible to install the coupling on power transmission line supports and wind the free length of the optical cable onto the frame.
This type of connection is used to ensure the safety of work performed at height according to the permit. To carry out such activities, a permit is required, issued by a labor protection specialist and endorsed by officials from among the managers, and the work itself is carried out by a group of workers under the guidance of foremen and supervisors. The most widely used are anchor bolts that have a spacer operating principle based on the expansion of the rear section of the sleeve when a cone-shaped sleeve is screwed into it. Among the well-known types of anchors, experts call driven, expanding, chemical, expansion and wedge structures. Each of them ensures reliable retention of the fastening part due to the use of the friction force between the contact surfaces of the bolt and the installation area, the thrust force, which ensures compensation of the effective stress by the resistance of the metal of the product. Increasing the diameter of the spacer sleeve when screwing a bolt into it ensures a reliable connection due to the combined action of thrust and friction forces.

Experts emphasize the importance of choosing the right type of anchor, based on studying the manufacturer’s documents that determine the specifics of each type of product. since the reliability of the system largely depends on the building material used at the point where the bolt is attached. Proper execution of fastening is necessary to prevent damage during operation of the parts that make up the connection and to ensure comfortable work in the support. Such a connection will ensure safety when working at heights, fastening heavy static (horizontal bars) and dynamic (diamond drilling rigs) structures.

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Fasteners for adjustable floor joists on studs with an anchor

You see a hairpin with an anchor or just an anchor for an adjustable floor in the photo. Anchor length 40 mm, stud thread length 160 mm, total length 200 mm. The anchor is equipped with two power washers and two locknuts.

The advantage of attaching joists to anchors is that the stud is attached not only to the joists, but also to the base of the floor. This eliminates even minimal horizontal displacements of the structure and, as a result, eliminates floor creaking.

Separately, we need to talk about the strength of the stud. Studs for joists are made (should be made) from steel with strength 8.8. For information, hardware is class 8.8. and higher (10.9 and 12.9) are high-strength fasteners used in the assembly of structures with high dynamic and vibration loads.

Fasteners of this class are used in the assembly of bridges and metal frames of buildings for various purposes. This once again emphasizes the reliability of the adjustable floor design with anchors.

What is an anchor

Initially, this is the name given to the type of fastener that is held in the mounting hole due to the expansion (wedging) of a special element (spacer sleeve or sleeve). The powerful friction forces that arise prevent the fastener from being removed from the mounting socket. This is the so-called mechanical anchor.

Now there is another type of anchor - chemical. It is attached using an adhesive composition made on the basis of synthetic resin. The mounting hole is filled with this composition, then one or another fastener is screwed into it: a bolt, a pin or fittings. Obviously, using “chemistry” we have a wider selection of fasteners.

Foundation bolts

Foundation bolts for construction work

During construction work, a huge number of different types of fastening elements are used that perform certain functions. A special place is occupied by threaded rods of various shapes, commonly known as foundation bolts. We will talk about the design of these fasteners, their types and use in this article.

Working principle and application

Concrete is a porous material with a heterogeneous structure. At the attachment point, forces are created - pullout, compression, shear, shear, bending, twisting, which the anchor perceives together with the supporting structure.

Three operating principles are used:

• When the surface of the bolt interacts with the base material, frictional forces arise. The expansion is created by metal collets and dowels.
• At the anchorage depth, the material resists crushing or fracture. This is facilitated by collet bushings on the fasteners, extensions, and the curved shape of the rod.

Effective loads are compensated by tangential stresses at the point of contact between the monolith and the metal rod during gluing or embedding. Adhesive anchors and smooth embedded parts work on this principle.

If the fasteners are selected incorrectly, damage to the structural material, the body of the anchor, or its tearing, bending, melting, burnout, and corrosion may occur. The consequences of this can be catastrophic - collapse of roofs, facades, walls or fences.

Improper design, fastening and operation of anchors in bridges, dams or overpasses leads to emergency situations. But even an unexpected fall of a book shelf, curtain rod or TV is not the most pleasant event, fraught with injuries and material losses.

To prevent this from happening, anchors are designed to withstand loads. To design fasteners, use the Manual for SNiP 2.09.03, which contains a classification, calculation algorithm, recommendations for the formation and marking of wells, and installation of bolts.

Anchors perform a load-bearing or structural function. In the first case, this is a loaded mount, where the following is connected to the base:

• beams;
• floor slabs, balcony consoles;
• trusses, columns;
• elevators, flights of stairs and landings;
• wall or finishing panels;
• communications, engineering equipment;
• window or door frames;
• awnings, canopies;
• extensions;
• ceiling lamps, hoods;
• dropped ceilings.

Hardware is used for laying joists on concrete floors or slabs with voids. Installation of anchor bolts is used when attaching hanging furniture and electrical equipment to the wall.

Structural fasteners are used to prevent displacement of parts of the assembly, the stability of which is ensured by their own weight, as well as their straightening during construction.

No building is erected without anchors. They are installed before pouring concrete or after - in a prepared hole or finished well.

Installation of anchor bolts in the foundation

In the foundation, anchor bolts are held in place by friction, abutment, and bonding . Friction is provided by loads that are exerted on the fastener and transferred to the foundation. The emphasis is the loads that the anchor perceives and compensates on its own, and gluing is the compensation of loads using tangential stresses with the base material.

If you need to secure a structure with a high level of asymmetry, it is better to order straight bolts with silicone or epoxy adhesive. Expansion bolts are used in areas where static or vibration loads are possible. Anchors with a conical end are recommended to be used for fastening structures that are subject to dynamic loads and are not able to withstand strong impacts.

Installation of foundation anchor bolts is carried out in several stages. First you need to carefully inspect the anchor bolts and make sure they are in good condition. Then you can begin work.

1. Preparatory work and determination of anchor attachment points. Remember that they should never be placed under doorways.
2. Installing bolts into the foundation base . The anchor should sink into the middle of the concrete base.
3. The distance between the anchors should be twice the insertion depth.
4. After the anchors are installed, you need to wait until the concrete mixture hardens . During this time, it is important to ensure that the anchor pins remain in a straight, vertical position.
5. The last stage of work is fastening . To do this, metal plates or a wooden board are installed.

Some types of anchors can also be installed in already hardened concrete. But in this case, a hole is drilled and a foundation bolt is inserted.

Types and methods of fastening

Anchoring is performed by various types of steel products, where one or several acting forces are used simultaneously - friction, thrust and intermolecular bonding during gluing.

Anchors are classified according to the following characteristics:

• purpose - foundation, ceiling, frame, universal;
• shape - straight or curved;
• design - solid or prefabricated;
• surface - smooth or threaded;
• contact area - for dense or porous material;
• installation method: hammering, screwing, gluing, through fastening.

Spacers

To solve critical problems, expansion anchors for concrete with nuts are used, where the friction force operates. They are a threaded stud with a conical tip and a sleeve. When screwed in, it wedges and firmly holds the bolt in the body of the concrete.

Advantages of these wedge fasteners:

• ease of installation of anchors in concrete;
• possibility of through installation;
• high load-bearing capacity.

Wedge hardware is used only for dense concrete. They need to be immersed deep enough and cannot be reused.

If a bracket is installed at the end of the rod instead of a nut, equipment can be suspended from such a mount.

Varieties of wedge anchors are sleeve or sleeve hardware. Available in the form of a bolt with a special wedging nut at the end or a stud with a conical widening. To ensure uniform distribution of internal stress, they are reinforced with double thrust.

These hardware are used in high and medium density concrete. A sufficient contact area with a small diameter of the rod allows it to withstand significant loads.

Drivers

For dense concrete, short drive-in anchors with metric threads and an internal cone are used. It wedges the base when screwing in a bolt or stud.

The mount is simply made and does not protrude to the surface. This option is used for installation of ceiling air ducts, ducts and other engineering equipment.

Hardware is hammered into the drilled hole, wedged with a center punch and a threaded rod of any length is screwed in.

Driven ones include a ceiling anchor or a dowel-nail, which is attached to the base through a part. This is a convenient connection for Armstrong ceilings, suspensions, slats, and mounting mortgages. Since the bolts are non-removable, they are often used as vandal-proof and fireproof fasteners.

Frame

Designed for securing window or door frames. The sleeve is cut along its entire length, and when tightened, a small wedging nut presses the structure against the opening to the desired position.

In the upper part of the sleeve, stops are located to protect against rotation and displacement around the axis.

Self-tapping screws for concrete

A strong connection is created by threads along the entire length of the hardware. When screwed into concrete, there is a high resistance to shear or pullout of the product. Thanks to this, the load-bearing capacity of the fastening is very high.

Concrete screws accept up to 100 kg of load, are easy to install and reliable in operation.

Expanding

These include the Molly bolt, commonly called a “butterfly”. Designed for mounting lamps, shelves, cornices, pictures in hollow concrete structures with low load-bearing capacity.

The collet on a bolt or screw is a drop-down skirt; when the rod is screwed in, it rests against the inside of the base cavity.

Special spikes on the outside of the collet go deep into the concrete and prevent the hardware from turning or moving during installation. The “butterfly” can be sold without a screw.

Chemical

A chemical anchor is a semi-liquid, quick-hardening mass with which studs or bolts are glued into the base.

The compositions provide a strong bond with concrete without point or local stresses. The load is evenly distributed along the length of the connection.

Problem fixing adjustable floor joists

The very name of the technology “adjustable floor” suggests convenient and relatively quick adjustment of the height of the joists. This is necessary to build a single horizontal surface of the future floor structure.

The adjustable floor logs rise to a height of 50 mm. The length of each log is 2 meters. In the floor structure, the joists are not fastened together. This “floating” floor design requires installation:

Violation of any of these requirements will lead, at a minimum, to creaking floors. As a maximum, focal squats of an adjustable floor.

The best indicators for reliable and durable fastening of adjustable floor joists are shown by fastening the adjustable floor joists in the form of metal bolts or studs with an anchor.

With nut

The structural elements of this type of anchor bolt are:

• a threaded rod, one end of which is made in the shape of a cone, and a nut is screwed onto the other;
• a spacer screwed onto a stud (its lower end has longitudinal slots on the side surface, which form peculiar petals).

Anchor with nut suitable for through installation in a pre-drilled hole

Reliable fixation of such a fastening element is ensured due to the fact that the petals of the spacer sleeve are unclenched, which occurs when they are exposed to the conical end of the pin. In order for the tapered end of such a bolt to begin to enter the bushing and open its petals, a nut is used.

Mounting parameters of anchor with nut

Fasten an anchor bolt with a nut in the foundation or any other building structure made of concrete, performing the following steps:

• drill a hole, the diameter of which must correspond to the cross-sectional size of the spacer sleeve;
• thoroughly clean the mounting hole;
• carefully hammer in the anchor bolt and nut using a hammer;
• By tightening the nut, you achieve reliable fastening of the anchor.

After the installation of the anchor bolt is completed, you can unscrew the nut from the top of the stud and begin installing the required item.

Installation procedure for an anchor bolt with a nut

When choosing products of this type, you should keep in mind that they demonstrate their effectiveness only if they are mounted in durable and solid materials (concrete, brick, natural stone, etc.). Manufacturers, in order to ensure high reliability and corrosion resistance of such products, make them from high-quality steel with a zinc coating.

An improved model of this type of anchor bolt is a double-expansion anchor, which, due to its design features, can be successfully fastened not only in durable concrete, but also in hollow and porous materials. Such a bolt has two bushings at once, which expand during the process of tightening the threaded element, creating a more reliable fastening in the wall or foundation.

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Self-tapping screws for concrete

They are available in hardened steel or regular stainless steel. They can be used if a person needs to fix a different type of anchor into concrete, but does not have a drill at hand.

Simply put, self-tapping screws are screwed into the material. There are small serifs along the entire length of the thread. You can screw in the screw using a screwdriver or manually.

Expanding

Supplied mainly for fastening lightweight structures to floor slabs.

When the bolt is tightened correctly, the collet begins to compress. Wings resting on the walls of the internal planes of the base. When the hardware is installed, the teeth are pressed into the concrete and thereby prevent the fastener from turning.

Chemical

When using this type of fastening, the compound is poured into the installation hole. It can harden in less than a minute. It is produced on the basis of special glue. This ensures the formation of a homogeneous connection between the bolt and the base material; the anchors do not need to be tightened.

Such anchors are supplied in two-capsule form. The ampoule is installed correctly in the hole according to the instructions. Then the fastener is screwed into it. It damages the capsules and releases the adhesive and hardener contained in them. They immediately begin to interact with metal and concrete and thereby ensure the strength of the structure. You can attach various things to it.

Wedge

These are non-removable structures, however, they are not difficult to secure. They, unlike most other anchors, do not have threads. There is no need to twist them. Therefore, such fasteners are installed in concrete only with a hammer.

When installed correctly, the anchor bolt is placed in the hole, then driven there until it stops, hitting the protruding part of the wedge with a hammer. After the process is completed, only a small anchor head will remain on the surface, onto which you can attach anything.

Four-segment

This is one of the most durable types of fastenings that are supplied to hardware stores. It is installed to secure heavy and large structures. There are 4 segments in the sleeve.

When installed correctly, a sleeve is inserted into the hole. It is equipped with restraining springs. A spacer is also placed in the hole. All this is carefully hammered into the material.

After the bolt is screwed into the hole, the structure wedges, which ensures reliable fastening. You can tighten the anchor with pliers or a wrench.

With nut

The design is a threaded rod. A nut is attached to one end, the other is made in the shape of a cone. A spacer sleeve is screwed onto the stud, the lower end of which has longitudinal slots. They form peculiar petals that hold the bolt in the concrete.

Correct installation of the anchor is as follows:

1. The material is used to prepare the place where the structure will be installed. The diameter of the hole in this case should be identical to the parameters of the sleeve itself.
2. The hole is cleared of debris.
3. An anchor bolt with a nut is placed into it using a hammer.
4. The man screws the nut as hard as possible. This ensures the reliability of the anchor fastening.

Hex head

In fact, this is a classic bolt that is supplied to all stores. When it is screwed into the spacer coupling, it expands it with its conical tip, thereby ensuring reliable fastening of the structure.

To secure the anchor itself, it is inserted into the prepared hole and carefully placed until it stops. Then a bolt is inserted into the anchor, after which it is tightened using a wrench.

On some variations of this design, instead of the hexagonal head of the anchor bolt, you can see a ring or hook on which you can attach various things.

Drums

Available in most stores. The rod has a hollow interior. There is a carving on it. There is also a striking element, complemented by a nut and a washer. A nut is screwed onto the protruding part of the anchor until it stops.

Impact anchor bolts are strictly not recommended for use in materials that have a porous structure.

Screw

Screw anchor bolts are easy to use. There are small slots in the middle of the spacer sleeve. They will not put pressure on the walls of the hole as much as with other types of anchors. There is a small nut at the bottom here. The anchor bolt is screwed into it. The structure is compressed along its length. Accordingly, the petals unclench.

Thanks to this feature, fasteners can be installed in concrete that has a porous structure, as well as brick. You can also attach various things to it.

Dimensions and characteristics of anchor bolts

Anchor bolts for concrete are classified according to size into three groups:

• small - with a diameter of up to 8 and a length of up to 55 mm;
• medium - up to 12x120 mm;
• large - maximum size 24x220 mm.

Mark the anchor according to the dimensions, indicate the thread diameter, drill number, thickness of the attached part, and the depth of the mounting hole.

For example, the designation of fastener M8 10/60-115 stands for:

• thread diameter - 8 mm;
• drill diameter - 10 mm;
• anchor length - 115 mm;
• The thickness of the attached element is 60 mm.

Technical characteristics - minimum pull-out force, permissible bending and maximum torque, weight of hardware - are indicated in the table of fastener parameters.

Anchors for concrete: weight and dimensions

Anchor bolt sizes are determined by the material used and the intended use of the product. Each manufacturer is regulated by general and internal standards. But there are parameters that are similar for all suppliers.

So, depending on the type of anchor, as a rule, the diameter/length of the product looks like this (in mm):

• wedge: 6-20/40-421;
• spacer: 5-24;
• scoring: 6-20.

The tables provide detailed information regarding the dimensions and total weight (in kg. 1 pc.) of popular concrete anchors, compiled on the basis of products from leading manufacturers (Hilti, Fischer, etc.).

Klinova

Installation instructions

Concrete anchors are installed before pouring the monolith or on a ready-made foundation. In the first case, a pin, bolt or other embedded part is secured with wire or welded to the reinforcement frame, then the solution is poured.

To protect the thread from contamination, it is covered with film. Subsequent work begins after the concrete has gained strength.

In the second case, the technology includes preparing the well and installing the product.

Drilling

Before installing an expansion, drive or expansion anchor bolt in concrete, prepare the hole:

• Mark the positions of the hardware on the base
• Using a drill or hammer drill, drill a hole 20 mm longer than the rod and with the diameter recommended by the bolt marking.
• Using a vacuum cleaner, clean the hole from drilling residues.

If you need to secure any part to the base, first drill it, and then make a hole in the supporting element through the finished hole.

Installation of anchor with nut

Installing an anchor bolt with a nut is used to secure structures of small thickness, for example, a wooden board or a metal corner, to the base.

The bolt is driven into the hole with a hammer, and the nut is tightened with a wrench. It is recommended to use a block of wood or a piece of board to avoid damaging the top threaded part of the hardware.

If the bolt needs to be removed, loosen the nut and remove it from the wall.

To hang household appliances or equipment on a vertical surface, use anchors with a bracket instead of a nut. It is screwed in all the way, making sure that the hook takes the desired position.

Chemical anchor installation

Liquid or injection dowels are installed according to the manufacturer's instructions. They are produced in capsules or cartridges.

Each type of installation has its own characteristics:

• The capsule is placed in the hole, then a bolt or pin is screwed in. Wait until the composition has completely hardened.
• The cartridge is loaded into the gun, the well is filled under pressure, and the hardware is installed.

Installation of anchor bolts in the foundation

It is recommended to install anchor bolts immediately after pouring the foundation or supporting base, before the cement has hardened.

First of all, it is necessary to study the plan of external, internal walls and entrance doors. Foundation bolts should be installed under external walls, so anchors should not be installed in doorways or under internal walls. Next, the bolts can be immersed in concrete precisely in the center of the future wall. However, do not recess them too much; the length of the protruding part should be approximately 5-7 cm. Anchor bolts should be placed along the entire perimeter of the wall. They need to be installed at a distance of approximately 40 cm from each other, but so that they do not fall under the doorways. Remember that the bolts must be strictly vertical, so they can be leveled using a level.

If you install anchor bolts into an already set base, then in this case you should use drilling. However, it is worth considering that drills of the appropriate diameter should be used to drill the mounting hole. While the base is being installed and cured, the anchor threads can be wrapped in cellophane to eliminate the hassle of cleaning up any hardened concrete particles on the bolts. Also, in order to avoid the tilting of the anchor bolt during the freezing process of the base, it is recommended to use a fastening device that is attached to the foundation formwork during the freezing period.

In some cases, the anchor bolt is installed before the foundation is poured. Then the bolts must be attached to the reinforcement or grating on the metal structure, then the solution is poured. This mainly happens during the construction of a strip foundation. After the foundation hardens, the anchor bolt can perform all its main functions.

Hello, dear blog readers, in the article anchor bolts we’ll talk about foundation bolts. Then why is this article called anchor bolts rather than foundation bolts?

Because at a construction site, when laying foundations, they are all called anchors, and this article will talk about their designation, types, tell you how they need to be fastened and what consequences can occur if they are installed incorrectly.

This article will be useful to builders who are just starting to master general construction work and, for example, you have to build a building from metal structures.

The installation of metal structures begins with the installation of columns strictly along the axes and dimensions specified in the drawings for concrete foundations. Metal columns are installed and secured to the foundations using anchor bolts; there is also an option without them.

Without bolts, embedded parts made of metal plates are placed into the foundations and the columns are welded to them. In the version with foundation bolts, it is easier to install the columns exactly vertically.

Let’s say it’s clear from the level that the column is not level and tilted in one direction; this is leveled by tightening the nut on the opposite side until it is level.

Let's look at the designation of foundation bolts and their classification, and then we'll talk about how to install them and what consequences can occur if they are installed incorrectly.

In the drawings, they are designated as embedded parts on the foundation according to GOST 24379.1-80 “Bolt 1.1 M24x900 C235”, what does this mean? The first numbers 1.1 of this type indicate that they belong to curved foundation bolts type 1, version 1. M24x900 thread diameter 24 millimeters, length L=900 mm, pin made of C235 steel.

As you understand, besides type 1, there are other types of bolts, there are only 6 of them with different designs. Type 2 foundation bolt with anchor plate, type 3 compound foundation bolts, type 4 removable foundation bolts, type 5 straight foundation bolts and type 6 foundation bolts with a tapered end.

Read in detail GOST 24379.1-80 “Foundation bolts. Design and dimensions." you can follow the link below.

Most often, on foundations, at least in my practice, bolts of the first type with curved ends were used. Which must be clearly set before pouring the foundation with concrete.

Hex head

The threaded part of such a fastener is a classic bolt, the reverse end of which also has a conical shape. Screwing into the spacer sleeve, such a bolt opens it with its conical shank, ensuring reliable fastening of the product to the wall or foundation.

Such an anchor should be secured by inserting and carefully hammering it into a previously prepared and cleaned hole. Then you need to securely fasten the bolt by tightening its hex head.

Procedure for installing a hexagonal anchor bolt

Bolts of this type, which may have a hook or ring instead of a hex head, are used to perform installation work on concrete, stone and other building materials with a dense internal structure.

Important to consider

When attaching storage to a wall or floor, you should adhere to a number of rules:

• fixation should be performed only on surfaces made of dense materials: concrete, brick, natural stone;
• the number of anchors is selected according to the number of mounting holes available in the safe body;
• if a particular model allows for fastening to both the floor and the wall, it is better to use it for the most reliable fixation;
• the lowest breaking load should start from 500 kg;
• the anchor should be selected based on the material of the wall or floor.

Attaching a safe to a wall or floor is not difficult if you have the necessary tools and installation skills. The process takes no more than 1 hour. You can carry out the fastening yourself or use the services of our specialists.

Drums

Anchor bolts of this type consist of:

• a hollow metal rod, on the upper part of which there is a thread for a fastening nut, and the lower part is a spacer coupling with longitudinal slots on the side surface;
• a striking element (nail), which, when driven into a hollow rod, precisely ensures the expansion of its lower part;
• nuts and washers, which are needed only to secure the required object with such a bolt.

The hole for the impact anchor is made with a drill slightly larger in diameter than the anchor itself

Thus, in order to correctly and reliably fasten such a bolt in a wall or other building structure, it is necessary not only to insert it into the mounting hole, but also to drive an impact element into it, which will open the petals of the spacer coupling.

Taking into account the fact that when installing such a bolt, significant shock loads arise, it is not recommended to fasten it in porous and fragile materials.

Impact Anchor Bolt Installation

How to anchor a safe to a concrete floor

In the current realities, the question increasingly arises of how and how to securely secure a safe in an apartment, because, firstly, not all merchants offer such a service, and secondly, many prefer to do the installation themselves. Securing a steel vault is usually done to prevent unauthorized removal. This can be done most reliably using anchor bolts on a cement-sand or concrete screed.

Regulatory conditions for the installation of safes are regulated by GOST R 50862-2005. For fastening, an anchor wedge fastening to the floor is used, which can withstand from 500 to 3,000 kg of tensile load. The optimal bolt length is 100-300 mm, and the diameter is from 8 to 20 mm. During installation, the following conditions must be taken into account:

• The thickness of the ceiling or subfloor must be at least 150 mm.
• If it is necessary to drill holes in places not provided for by the design, it should be taken into account that the tightness of a fireproof or backfill safe cannot be broken.
• Independent violation of the integrity of the case may lead to termination of the certificate.

Four-segment

The design of such an anchor bolt does not include a wedge part, and the expansion of the spacer sleeve, divided into four segments by longitudinal slots, occurs when the bolt is screwed in, which moves the tetrahedral element in its internal cavity. The four lobes, which are formed by slots on the side surface of the spacer, are initially compressed and form the conical tip of such a bolt. When a bolt is screwed in, which moves a threaded tetrahedral element inside the spacer sleeve, the segments expand, which allows the anchor to be securely fastened in the mounting hole.

The fairly large expansion of the lamellas of this anchor ensures responsible fastening in various types of materials

The petals of such a product open quite wide and this happens very carefully. That is why it can be mounted in porous and even hollow materials. The threaded element, which is usually not supplied with such an anchor product, can be a bolt with a regular hex head or a bolt whose upper part is crowned with a ring or hook.

Installing a 4-segment anchor

Joists on a concrete floor: how to fasten them (with anchors, screws, corners), and place them correctly?

Wooden logs are essential to ensure natural ventilation of the underground space and better heat retention in the premises. Thanks to the use of logs, the floor covering can last much longer. However, among people who do not have much experience in construction, you can often hear the question: is it necessary to attach joists to a concrete floor? Experienced craftsmen know that for a truly durable flooring that does not change its geometry under load, and for its long service life, it is imperative to correctly fix the logs on any supporting structure, including on a concrete screed.

Now that it is clear whether it is necessary to attach the joists to the concrete floor, it is worth noting that this task is not difficult, does not require special skills and knowledge, and, therefore, can be done by any home craftsman.

General recommendations

In order to correctly install anchor bolts, it is necessary to take into account the type and strength of the base, select the optimal type of anchor for a particular part and determine its load capacity.

And although some types do not require high precision hole drilling (for example, expanding), the more accurate it is, the more reliable the anchor’s adhesion to the base.

Information to note : Liquid glass , Solvent 646, white spirit.

Anchor bolt. Installation operating principle.

Anchors for floor screed

In addition to leveling, installation of such floors is necessary in the following situations: • raising floors on lower floors in order to improve living comfort;
• if the floor consists of several levels; • for placement of soundproofing materials; • when carrying out redevelopment, to remove communication nodes under the floor; • when the floor level is lowered by 10 centimeters or more due to reconstruction. The floor anchor is widely used in: • screeds; • monolithic foundations; • floors with voids.

Installing floors on anchors To install floors on anchors, you do not need a large number of various tools. A simple set will be enough: to remove the posts - a grinder, a tool for drilling and tightening nuts and bolts. Installation is carried out as follows: 1. Drilling holes in the bars for the logs and the base for the racks. To do this, take a block, lay it on the base and make a hole in the joist and the base. If there are significant loads in the future, they should be drilled more often. There is a hole in the joists for the nut; 2. The logs are installed at a distance of 20-60 cm from each other, also if the future load is large, the distance between them should be reduced. Logs from the walls must be placed at a distance of 10 cm; 3. Racks are installed in the finished holes; 4. The logs are attached, starting from the end. The optimal height is set using an adjustable bolt; 5. The process of tightening the bolts is carried out only after the final alignment of the joists; 6. Now you need to remove the protruding posts. To do this you will need a grinder; 7. At the final stage, rough plank or plywood floors are attached to the joists, having previously protected them with impregnation from the effects of fungus and moisture.

Source

Drivers

A drive-in anchor is the simplest anchor-type fastener, the design of which consists of a spacer sleeve with a conical-shaped internal hole. To install such an anchor bolt at the required point in the building structure, it must be hammered into the mounting hole, and then a threaded element must be screwed into it, which will ensure the loosening of the bushing petals.

The material for the manufacture of such fasteners, the correct installation process of which can be seen in the video, can be galvanized steel or brass.

Attaching a drive-in anchor

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Anchors for floor screed

Do not confuse an adjustable floor anchor with a wedge anchor, although they look very similar!

The need for this section is long overdue, since the modern hardware market is saturated with a huge assortment of different anchors, different in purpose and functionality; confusion often arises in this issue, which we intend to eliminate.

The easiest way to tell the difference between an adjustable floor anchor and a wedge anchor is to simply look closely at their designs. Both anchors consist of 3 elements

: threaded post, tubular element and nut with washer.

The difference is the following: the anchor for the adjustable floor is collapsible

, that is, the nut with a washer and the tubular element can be removed,
but the wedge element cannot
, only the nut and washer can be removed, its tubular element is not removable!

DIFFERENCE IN THE OPERATING PRINCIPLE

And now to the facts, 80%

All flooring installations that we have encountered are
slabs with voids
, and
a wedge anchor will not work
. In the empty space of the slab there is nothing for him to interact with.

In floors, the point is the following: if at least one anchor does not stand clearly and reliably, then creaking in this place is inevitable.

It is no coincidence that the anchor for an adjustable floor has such a design; its technical properties are ideal for installing wooden floors and all this has been tested over years of practice.

Please note that in traditional wooden floors on wedges and bosses, which are attracted by frame anchors and other types of fasteners, there is the same problem.

Moreover, all these bosses and wedges made of different materials are part of the anchoring mechanism. That is, the head of the same frame anchor rests on top of the joist and, through a pile of “linings,” attracts it all to the floor, which means this pile of “linings” is part of the fastening.

Source

Screw

The design of the screw fastener, which is very easy to use, differs from all other anchor-type products. The slots on the spacer sleeve of such an anchor, which ensure its expansion during installation, are made in its middle part and have a weakened design. The lower part of such a sleeve is a nut into which the anchor bolt is screwed, compressing it along its length and ensuring the opening of the petals.

Screw anchors are called anchors of different designs.

The process of installing a screw anchor bolt can also be seen in the video. Such an anchor can be fastened in “weak” materials: porous concrete, brick, etc.

Briefly about anchor fasteners

The method of fastening a part is determined by the parameters of the payloads, which ensure its strong fixation in a specific material. These can be frictional forces, counterforces in a persistent system, and adhesion with the participation of chemicals. Thus, securing the desired structure will be no more difficult than painting OSB inside the house.

To install the desired anchor in concrete, it does not hurt to familiarize yourself with its main technical characteristics, which include the following parameters:

Sometimes the production of non-standard products is allowed. For example, anchoring to the floor in certain cases must take into account the technology and structural features of the object. In this case, the project is being developed according to the conditions of SNiP 2.09.03. The optimal fastener is selected taking into account the diameter and length of the fastener. In most cases, these values ​​are indicated in the labeling:

The information presented in the table is quite sufficient for the optimal selection of the required fasteners. Let's say that anchor bolts for bricks not only have certain installation features, but also carry a specific functional load. For example, a knot with a ring is designed for hanging a chandelier or rope.

Methods for installing joists on a concrete floor

Methods for attaching joists to a concrete floor come down to four main options, after familiarizing yourself with which, any master can choose the most suitable one for himself.

Fastening the joists with self-tapping screws

This is the simplest way to attach joists, but, unfortunately, it is not suitable in every situation.

People often ask, what step of attaching the joists to the concrete floor is better? There is no strict standard here - the step can vary from 40 cm to 80 cm, but on average you can safely focus on half a meter.

The logs will hold securely enough only when there is a small gap between the base and the beam. This should definitely be taken into account by those who want to know how to properly lay joists on a concrete floor.

Fastening joists with anchors

Anchors, unlike self-tapping screws, not only rigidly fix the logs, but also attract them to the concrete surface. Thanks to this installation, wooden beams will be held more securely, which is why most craftsmen prefer to use anchors. In addition, this powerful fastener will restrain the deformation of the wood to a certain extent, especially if it has not been sufficiently dried beforehand. But it is much more difficult to pull an anchor out of a concrete base than to drive it in, so workers will have to spend a lot of effort during dismantling.

Be that as it may, when using anchors, the floor covering will not swell, but it may sag. To avoid the latter, it is necessary to install gaskets more often.

Before installing the anchor, you need to drill a larger diameter hole in the beam to accommodate the bolt head.

The anchors should be spaced at intervals of 60-100 cm, and their length should be sufficient for them to penetrate approximately 6 cm into the concrete. Most often, anchors with a diameter of 10 mm are used. Typically one joist is held in place by 4-5 anchors.

Video about attaching joists to a concrete floor with anchors:

Fastening the log to a metal corner

It becomes inconvenient to work with logs 10 or more centimeters high. To fasten them, it is better to use steel corners, which will touch the joist with one shelf and the concrete base with the other. In this case, fixation is carried out: to the concrete - with dowel-nails, and to the timber - with self-tapping screws. In this case, the main load should fall on the gaskets, and not on the fastening elements, because the corners should only fix the position of the beam.

In order for the lag to be better bonded to the surface, you need to use self-tapping screws whose threads do not reach the head.

You can also attach wooden elements to a concrete base using a galvanized steel corner. The installation process is as follows:

Video on how to secure joists to a concrete floor with corners:

Adjustable joists

There is another option for attaching joists to a concrete floor. For this, a rectangular stand is used, which is attached to the base with four dowels. In the middle of this stand there is a pin that pierces the beam through and through.

By rotating the nut located under the beam, you can accurately set its height, and use the upper nut to fix the element in the required position.

This system is not that difficult to install; it is attached to the floor with dowels, and you will need to make a hole in the joist for a pin. The frequency of installation of stands under it depends on the cross-section of the log; however, in any case, it is not recommended to make an interval of more than 1 meter. This option of attaching the log to a concrete base, although recognized as optimal, however, due to its high cost, has not become very popular.

After fixing the logs, a subfloor made of boards, OSB or similar materials is laid on them. If the work is done efficiently, the appearance of the finished floor can be impeccable.

Attaching joists to concrete pillars

Logs are attached to concrete pillars in the same way. The same fasteners are used here, but intended for poles.

Step-by-step instructions for attaching joists to concrete with your own hands

Attaching wooden joists to a concrete floor is easy, even on your own. There are several mounting options, and below are the steps of one of the standard methods.

Materials and tools

Fasteners

The question of how to secure joists to a concrete floor has different answers: simple or adjustable structures can be used for this. The latter use special screws, by tightening which the logs can be leveled. In addition, the choice of fasteners and fastening methods depends on what kind of joists are used.

Most often, the lags are fastened to the concrete floor with metal anchors or self-tapping screws with polypropylene dowels, the dimensions of which are selected depending on the cross-section of the selected beam for the lags.

The choice between anchor nails or self-tapping screws is determined by the following:

With modern technologies, logs under a wooden floor could not be secured at all, however, such a solution would greatly increase the likelihood of the floor covering being skewed or the logs moving from their original location. Therefore, when it comes to fastening lags, it is best to rely on old methods that have been time-tested more than once.

However, fastening may not help if low-quality or unsuitable lumber or incorrect fasteners are chosen for the work.

Tips for choosing lags

When choosing logs for a concrete floor, you need to pay attention to the following points:

For reasons of economic feasibility, you should not take expensive wood, because spruce, fir or pine, if properly processed, can last no less. The appearance of the material is not particularly important, however, you need to sweep away specimens eaten away by grinders or blackened by mold. Evenness of tone and correct geometry of the lag are of less importance. For this work, grades B and BC with a humidity not exceeding 20% ​​are suitable. As is customary to work with lumber, they should be stored in a dry room for some time so that they equalize the humidity with the surrounding atmosphere.

Before attaching the logs to the concrete floor, all wooden elements must be thoroughly impregnated with an antiseptic.

Tools

Since the task is how to lay logs on a concrete floor, you will have to use the following tools in your work:

In addition, you will have to spend money on waterproofing, which must be spread over the entire surface of the concrete. When calculating the amount of material, you need to add another 10-15 cm overlap to the floor area.