Introduction to anchor screws

Anchor screws are screws used to fasten equipment to concrete foundations. Generally used in railway, highway, electric power enterprises, factories, mines, Bridges, tower cranes, large span steel structure and large buildings and other infrastructure. Have a strong stability.

Anchor screws are screws used to fasten equipment to concrete foundations. Generally used in railway, highway, electric power enterprises, factories, mines, Bridges, tower cranes, large span steel structure and large buildings and other infrastructure. Have a strong stability.

Anchor screw specifications

Anchor screws generally use Q235, Q345, that is, light round. I don’t think I’ve seen threads used yet, but not if the force requires it. Rebar (Q345) is of great strength, making the thread of nut is not as easy as light round. For the smooth round anchor screw, the buried depth is generally 25 times its diameter, and then make a 90 degree hook about 120mm long. If the diameter of the screw is very large (such as 45mm) buried too deep, you can weld the square plate at the end of the screw, that is, it is ok to do a big head (but there are certain requirements). Buried depth and hook are to ensure the friction between the screw and the foundation, so that the screw will not pull out damage. Therefore, the tensile capacity of the anchor screw is the tensile capacity of the round steel itself, the size is equal to the cross-section area multiplied by the design value of the tensile strength (140MPa) is the design of the allowable tensile capacity. The ultimate tensile capacity is the cross sectional area (in this case, the effective area at the thread) multiplied by the tensile strength of the steel (Q235 tensile strength is 235MPa). As the design value is biased towards safety, the tensile strength of the design is less than the ultimate tensile strength.

Installation process of anchor screws

The installation of anchor screws is generally divided into 4 processes.

1. Perpendicularity of anchor screws

Anchor screws should be installed vertically without inclination.

2. Laying of anchor screws

In the process of anchor screw installation, often encountered is the second grouting of the dead foot screw, that is, when watering the foundation, the reservation hole of the anchor screw is set aside on the foundation in advance, the anchor screw is put on when installing the equipment, and then the anchor screw is watered with concrete or cement mortar.

3. Anchor screw installation — tighten

4. Record the installation of anchor screws

In the installation process of foot screws, corresponding construction records should be made in detail to truly reflect the model and specification of foot screws and provide effective technical data for future maintenance and replacement.

General installation of high accuracy of embedded cage to be made first (need to be first through the screw hole on the embedded steel plate, and nut compression. Before pouring, bind the embedded parts to the template and fix it well, so that the installation size of the foot screws can be guaranteed. If you want to save material, can also be fixed by steel welding, welding after the completion of the need to check the geometry. At this point, the foot screw installation is truly complete.

What are the reasons for the standard anchor screw corrosion

Countries have different specifications, such as British, legal, German, Australian and American standards.

Cause of corrosion of anchor screws

(1) The reason of the medium. Although some anchor screws do not contact the media directly, for a variety of reasons, corrosive media may be transferred to the anchor screws, causing corrosion of the anchor screws.

(2) Environmental reasons. The screws of carbon steel will corrode in wet conditions.

(3) The reason of screw material. In the design, although the anchor screw is selected according to the provisions, but often only consider the strength of the screw without considering the special conditions, the anchor screw will be corroded in the process of use, so there is no use of corrosion resistant materials, such as stainless steel.