Anchor for concrete. Types of anchors

Fastening of products to concrete and a brick is a problem for builders, industrial enterprises, and also homeowners. If the fastening to wood and plastic is not difficult, then with brittle materials there are problems and special devices are required. Here the anchor for concrete comes to the rescue. Usually they are made mortgages when pouring the foundation, socle, walls. But in the future there may be a need for re-profiling or repairing the premises. Here we need other elements.

What is an anchor

Anchor is a part intended for fastening of products and structures to solid bases of building materials, first of all, from concrete, stone and brick. A hole is drilled under it , in which the fastener is held by friction, gluing or abutment. Installation of the anchor in concrete is done by the way of wedging the metal galvanized fasteners of a special design.

What does the reliability of the connection depend on?

The quality of the connection is influenced by the following factors:

• Characteristics of the base (concrete, brick, stone);
• Correspondence of the sizes and type of fastening to the applied loads;
• Technology of preparation and installation;
• Strength fasteners.

Anchor is hammered into a hole drilled in concrete or brick construction: foundation, wall, partition, slab. With its help fasten beams, channel bars, suspended ceilings, chandeliers, handrails, load-bearing structures of great weight. In this case, the base must be strong enough.

How to fix the anchor for concrete

Anchors are attached by wedging the bushing inside the drilled hole or on the glue.

Types of mechanical anchors

The simplest fastening is a screw anchor with internal thread. It is inserted into a previously prepared hole, unclamped with a special device and screwed in the fasteners.

A common type is a concrete anchor bolster with a wedge. It is designed for high loads and with its help you can install even machines or heavy garage doors. The principle of operation consists in wedging the conical shank of the shell, which is attached to the pin, and creating an obstacle to the reverse motion. In this case, the base of the building material must have the necessary mechanical properties to withstand the spread and weight load.

To tighten the wedge anchor after its installation, you need a special core punch, which is inserted inside and wedge the hub with a hammer. Then the tool is removed and the fixing screw is wrapped.

In another design of the wedge anchor, the tightening is done using a nut that rests against the surface of the base, moving the threaded pin and the cone at the end. The cone goes into the sleeve, which expands and the fastening takes place. If the bushing is made with teeth, it cuts the concrete, forming a cone inside. The fastening is stronger, since in addition to the expanding force there is an additional emphasis in the axial direction.

Another device contains a tapered system that tightens the spacer sleeve from both sides. Due to this, the surface of friction increases 2 times. Such anchors are attached to the construction of medium and large gravity to concrete and natural stone.

The rod anchor is arranged by analogy with the wedge, only has a long length. It connects multilayer systems, for example, insulating and facing materials. The inner rod can be cut to the required length. The end with the wedge is inserted into the hole drilled in the concrete, and on the other hand the rod is tightened with the nut and washer. Rod anchor is often used for finishing facades of buildings.

The frame anchor contains 2 zones of wedging, one of which is located in the base, and the other - in the attached part. When tightening the bolt, it is firmly fastened with a double puff.

Depending on the purpose, the type of anchor for concrete is chosen. Dimensions, types and characteristics are given in the tables, according to which they are determined by their compliance with design loads.

Chemical anchors

Anchors for concrete can be installed on an adhesive, for example, a resin resin. To do this, they are filled with a well cleaned 2/3 hole. After the anchor is inserted forward-rotational motion. Instead, you can use a conventional hairpin or other fasteners. After the glue hardens on the anchor, it is possible to fasten the structure or part. If properly installed, it is capable of withstanding significant loads. The chemical anchor is indispensable for installation in porous materials, for example, in foam concrete or aerated concrete. The mechanical fastening is not suitable here because of the low strength of the base.

Improving the reliability of the connection is created by using as an adhesive inorganic (cement) and organic (highly reactive resin) components. Cement provides good compatibility with the substrate and high mechanical properties.

Chemical anchoring fixes reinforcing bars, bolts, threaded studs, bushings with internal threads. Special injection systems for glue supply have been developed. It is injected into the junction quickly and in batches, which minimizes the consumption. In this case, cylinders with different capacities and solutions with different polymerization rates are used. Pressing pistols can be pneumatic or run from batteries.

For chemical anchoring it is important that the holes in the base are clean. For this purpose, special blowing devices with brush sets are used in the set of equipment.

In the case of porous building materials, it is preferable to choose chemical anchors for concrete. Prices here are more dependent on the type and amount of glue, as well as the injection system, with which you can attach even simple embedded elements: studs, bolts, fittings, etc.

Conclusion

The correct choice of the type of anchor for concrete and the technology of its installation will make it possible to create a reliable and durable connection. For all types there are tables with characteristics on which you can find the optimal solution.