Anchor bolts for concrete - variations and device principle

Often, people have to fix any elements (shelves, pots, etc.) on concrete walls. This is a rather complicated operation, but an anchor screw for concrete can help. It is a universal fastener, which we will discuss next.

Varieties

Для рядового обывателя данный элемент кажется весьма простым, но на самом деле это не так. Существует множество разновидностей такого крепления. О них вам расскажет наша инструкция (см.также статью «Гвозди по бетону – возможность создать прочный и надежный крепеж»).

Wedge

In order to install it, you must first drill a hole. The screw will be installed in it. The most important difference of this variety from all others is that the fastening occurs without a shirt.

Inside the sleeve there is a wedge that expands when the bolt is screwed. After clogging the anchor, it is necessary to tighten the nut that holds the rod due to expansion of the sleeve. Wedge anchor bolt for concrete is used for fastening structures of great weight, as it has good strength.

Spreader

To date, this species is the most common. The sizes of anchor bolts for concrete of this type can be different: 2–12 cm in length and 0.4–2 cm in diameter.

Such bolts have a sleeve extending along the entire length of the rod. Inside it there is a thread on which the head is seated, bursting the sleeve. As a result of the action of this simplest mechanism, fixing occurs.

Like the previous type, it requires drilling a hole.

Razzhimna

Inside it is a sleeve with petals and a special nut. In the process of twisting, she spreads the petals. The use of such fasteners is very practical.

It should be noted that such an element is easy to dismantle. Such a need may arise, for example, if it is planned to cut reinforced concrete with diamond circles. The presence of metal elements in the surface can damage the instrument, so they must be pulled out first.

Chemical

Such bolts are glued to the material: special packaging with glue is placed in the prepared hole. Due to the pressure of the anchor, the adhesive composition is squeezed out, providing a very secure fit. The price of such a product is quite high, so it is not too popular.

Hammerhead

Such an attachment has a sleeve with an internal wedge and special cuts. They provide expansion sleeve when hitting the screw. You need to hit the anchor itself, as a result of which, the wedge will rest against the bottom of the hole.

Tip: do not use such fasteners, if we are talking about the old crumbling surface. After all, its installation is not complete without a hammer blow.

Such screws can be metal or polymeric (they have a similar principle of action with expansion bolts). There are also nylon varieties that are distinguished by the presence of a threaded bolt in the form of a shark tooth. This mount will be one of the most reliable.

Description

Having learned all the currently known varieties, you can get acquainted with the main features of the described product. It is worth saying that there are quite a lot of them (also learn how concrete dust removal is made).

Working principles by which he is held

First of all, let us consider what forces this fastener holds in the surface, providing a high degree of reliability.

• Friction. The loads are transferred to the substrate due to the friction of the screw. To accomplish such a process there must be a bursting force.
• Emphasis - compensation of loads due to the resistance force.
• Gluing - compensation of loads due to shear stress in the joint area of ​​the bolt and the surface material.

In most cases, there is a combination of two or more of the principles described above. This is the way to ensure the highest reliability.

Size range

Seeing the label, many people do not understand what these numbers mean. In fact, they are put in accordance with GOST and can provide useful information.

So, seeing, for example, a bolt with a size of 8 * 6 * 60, you need to know that:

• 8 - outer diameter (in mm).
• 6 - inner diameter.
• 60 - total length.

However, on the shelves of shops you can find products with a different label. It may be foreign samples, or not certified products. In any case, be sure to ask about this from the seller.

Breakage options

Fixing anchor bolts in concrete may collapse. This can happen only for two reasons: improper installation and exceeding permissible loads.

There are several varieties:

• Pulling out - implies full or partial tearing of the screw from the surface. In most cases, the physical integrity of the base is maintained.
• Pulling out основания - absolute damage to the connection due to violation of structural integrity. It is usually caused by the fact that on the basis of the force are greater than the allowable rate.
• Izlom - damage caused by too strong bending forces. Usually destruction happens during installation.

Important: do not allow the load on the fasteners to be more than 25% of the pullout force.

• Slice - absolute destruction along the base boundary due to the excess shear forces.
• Melting.

Note! Do not forget that the anchor bolt for aerated concrete can be subjected to all the above impacts. Therefore, before installing, calculate the possible options.

Tips for choosing

To select a truly suitable element, you must consider the following factors:

• The type and size of the loads to be supported by the fastener.
• The type, strength and structure of the base, as well as the method of installation.
• The type and size of the item to be hung.
• The distance between adjacent holes (if we are talking about a large number of them).

Installation Recommendations

Now we will tell how to install this element with your own hands.

So, you need to do the following:

• Drill a deep hole in the wall. Its diameter should be 1-2 mm greater than the thickness of the bolt.
• Next, you need to clean the resulting hole from dust and insert an anchor into it.
• At the end you need to fix it.
• If it is a chemical screw, it is inserted into the hole with a pistol.

If you have a thick and massive wall, then diamond drilling of holes in concrete will help you. This technology will cope with its task in seconds.

Posleslovie

At this point we will put an end to our story, but if you have any moments that remain incomprehensible, then you shouldn’t worry (learn here what a concrete hardening accelerator is).

In the presented video in this article you will find additional information on this topic, due to which you will be able to find answers to all questions. So take some time and look at it.