Anchor bolts are one of the main fasteners, without which it is difficult to imagine the construction and repair process. Without these indispensable helpers, the installation of almost all designs is impossible, at the base of which concrete lies or brickwork. From the German language, the word "anchor" translates as an "anchor", and this is not in vain. The principle of operation of anchor bolts itself is built on the fact that, due to its design, he, as it were, holds the attachment in the concrete.
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Anchor bolts. Areas of use
The history of an anchor bolt began pretty recently. Previously, wooden corks used as this fastener. From a piece of wood, a plug was cut with a large diameter than the dimensions of the screw. Then the hole was drilled in concrete, slightly smaller diameter and scored a plug into it, in which, in turn, screwed up the screw. Under his action, the plug was expanding and did not fall out of the hole, holding the entire design.
True, such an "anchor" had a lot of flaws. First, wood has not entirely suitable for these purposes. Such tubes very often collapsed under the influence of moisture in concrete. In addition, they could not be used for the installation of such heavy structures as a suspended ceiling. Secondly, these tubes needed to be made manually, which occupied a lot of time. Imagine to extend more than a hundred pieces of such fasteners to make repairs in one room.
To solve these problems, engineers have developed plastic anchors. They were able to remove some of the difficulties faced by builders earlier. Such elements have become more accurate in size, they are easier to mount, and they are less susceptible to the harmful effect of the external environment. However, they still did not become panacea. The fact is that plastic can not withstand heavy loads under which it is usually deformed, which leads to the destruction of the structure.
Almost all problems were solved using metal anchor bolts. Thanks to them, it was possible to install quite heavy structures on the walls, such as air conditioners, satellite dish brackets, fix massive metal doors, cable garters for which an anchor bolt with a hook is used. For the same purpose, an anchor bolt with a ring can fit perfectly. Due to various configurations of metal anchors, they are multifunction and are suitable for solving various tasks.
In industry, anchor bolts are used for quite a long time. If you look at the power line, you can see that her supports stand on a concrete foundation screwed by such bots. They are exhibited according to drawing data and poured concrete. Then the metallic design is fixed to anchors. Almost all heavy equipment on large industrial facilities is installed on the anchors. The calculation of the anchor bolts for such designs is one of the important tasks at the design stage of the object.
Classification of metal anchors
Speaking about the classification of these fasteners, several categories can be distinguished.
Anchor bolts are distinguished by a method of action into two groups:
- Chemical anchors. The method of action of this type of fastener is based on a substance that is concluded in a capsule inside a dowel. When the worker installs an anchor and starts to twist it, the capsule with the adhesive substance is broken, and fills all the hole. Such anchors are indispensable when in the walls or in the slabs of the overlap to which they are installed, there are emptiness. However, these fasteners have their drawbacks. When installing them, before fixing the design to them, you need to wait a little time.
- Mechanical anchors. They are more common and popular than chemicals. The principle of operation of such an anchor is based on the proprietary of the metal sleeve, due to the spacer sleeve, which moves along the inside surface of the heel liner or bolt.
Depending on the design of the anchor bolts, they are divided into several basic groups, distinguished by the principle of action.
- Wedge. This type of anchor works through the wedge at the end of its sleeve. When it is clogged into the hole, the wedge moves along the inner surface of the sleeve and thereby cuts it, due to which an anchor bolt is strengthened in the hole. In some models fasteners, the slicing of the sleeve occurs due to the installation of the special rod, which is consequently removed, and a special stud is located in its place.
- Scored. The fasteners of such anchors occurs at the expense of specially produced edges of the sleeve. These parts of the fasteners are usually made of soft metal and when scoring anchor is simply folded, fixing it in the hole. Such a simple design of the anchor requires a clear observance of the size of the opening both in length and in diameter. Use such a type of fasteners mainly in monolith concrete or stone.
- Scroll anchor or butterfly. This fastener is used primarily in thin-walled materials. This is a cross-cutting anchor with a special design of a sleeve that has slits in the middle. When the screw of the anchor is spinning, its rear moves along the thread, thereby deforming the sleeve. It is revealed, the image of the so-called petals that press the anchor to the inner surface of the plate. These fasteners are used to attach structures to plasterboard, plastic or fiberboard. The low weight of the anchor bolts of this type is perfect for solving very complex tasks.
- Purchase anchor. This type of fasteners are the most popular and popular. Such popularity is based on the fact that they do not require the exact dimensions of the depth of the hole. The principle of its work lies in the collet method of expanding the sleeve due to the movement of the cone-shaped sleeve. Apply such anchors in a full-length brick or concrete.
The material for the manufacture of anchor bolts is high-alloyed stainless steel, which are additionally covered with anti-corrosion coating. The inner bolt or stud is made with a metric thread with a diameter of 6 mm to 30 mm. Qualitative indicators for anchors are the standard for the discontinuous force and on the cut.
How to install anchor bolt
This operation does not require special knowledge or skills, and it can be properly installed such fasteners. On the Internet it is possible to find a lot of videos, how to mount anchor bolt. Algorithm for installing anchor bolt with nut Next:
- We estimate the status of the wall. Quite often in the houses of the old building on the walls, a layer of plaster was applied, which could not hold the anchor. Therefore, the calculated length of the fastening element must be increased by the thickness of the plaster. That is, if an anchor is needed for mounting a bracket with a long 50 mm, and the layer of plaster is 20 mm, then the minimum length of the anchor bolts should be 70 mm.
- We select the drill with a diameter of 0.5 mm less or equal to the size of the anchor bolt. It is not recommended to drill too large hole. The fastener sleeve should enter a drilled hole with a little effort.
- We apply markup to the surface. It is necessary to do this as accurate as possible, otherwise after fixing the anchor, it will already be impossible to pull it out.
- Drilling holes in concrete perform a perforator or a drill drill with a special carbide tip. Brick is better drilled without strikes so as not to damage its structure.
- A drilled hole must be cleaned from dust using a brush, a vacuum cleaner or a sphailed aircraft.
- Next, with light blows of the hammer set the anchor sleeve. If this fails to do, do not beat the hammer in it, you can spoil everything. Come one more time the drill, slightly shaking the drill to ruin the hole.
- Then screw the anchor stud in the sleeve, then screw the nut on it. When the nut reaches the sleeve, clamp it with the key.
Fastening anchor bolts "Butterflies" Cornice to the suspended ceiling
If you have in the house of the suspended ceiling, then install the cornice is better for a special anchor, the so-called "butterfly". To do this, we take cornice and drill holes in it, with a diameter of equal dimensions of a dowel screw. Then, on the drilled wells, we make tags on the surface of the ceiling. After that, in the ceiling, we send the holes, with a diameter of equal gabarites of the sleeve.
Install the sleeve in the hole and fix. One of the structural features of such anchors are hooks at the end of the sleeve, due to which it clings to the surface and does not scroll. Then we take the cornice and fix it to the screws. When you scroll the screws, the sleeve is deformed and reveals, holding the cornice.
Installation of anchor bolts for the foundation
If you need to install a metal structure to a concrete foundation, then after the base is freezing, drills the hole with a diameter, slightly more than the size of the bolt. Then the well fill in a special solution and lower the bolt there. After drying the solution, we install the metal structures.
