Precautions when setting the hook group correctly

If the hook group on the component breaks, pulls out, or pulls out, it will break the component and even cause a personal accident, so it must be set correctly.

When designing the hook group, it is stipulated that the hook group should be made of Grade I steel. It is strictly forbidden to use cold-worked steel bars or Grade II and III steel bars because these steel bars are poorly plastic and easy to be brittle. The depth of the buried member of the hook group shall not be less than 3n times the diameter of the steel bar of the hook group, so as to prevent pulling out. When calculating the number and size of hook groups, the safety factor should be greater than 4. Each hook group can be calculated according to two intercepts; when four hook groups are provided on one component, only three lifting rings are considered to function at the same time because of the uneven force. Calculated by force on 6 sections.

The position of the hook group in the component should consider whether the force is reasonable after lifting the component and whether the weight is balanced. Therefore, you must pay attention to the following:

(1) The hook group and the steel frame are applied with strong lead wires to prevent collisions in production and displacement of the rings. At the same time, according to the force state of the component when creping, the position of the lifting ring should be determined. The hook group should be placed under the stressed steel bar, so that the hook group can transmit the force to the entire steel bar skeleton.

(2) The hook group should be placed inside the main rib and should not be placed inside the protective layer.

(3) The hook at the lower end of the hook group should have a straight part. If there is no straight part, the nail is effectively hooked to the steel frame.

(4) The hook group exposes the length outside the member so that it can be easily inserted into the hook. It should not be too long, otherwise it will easily cause the concrete to crack. If the hook group is used as a component connection, and the exposed part is long, a hook can be added to the hook group to increase the concrete split surface.