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Selection and common knowledge of foundation bolts

2020-06-27

The tensile capacity of the anchor bolt is the tensile capacity of the round steel itself, and the size is equal to the cross-sectional area multiplied by the allowable stress value (Q235B: 140MPa, 16Mn or Q345: 170MPA) is the allowable tensile bearing capacity during design.

Anchor bolts generally use Q235 steel, which is smooth and round. Rebar (Q345) has high strength, and it is not easy to make the thread of the nut. For smooth-round anchor bolts, the buried depth is generally 25 times the diameter, and then a 90-degree hook with a length of about 120mm is made. If the bolt diameter is very large (such as 45mm) and the buried depth is too deep, the square plate can be welded to the end of the bolt, that is, a large head is enough (but there are certain requirements). The buried depth and the hook are to ensure the friction between the bolt and the foundation, so that the bolt will not be pulled out and damaged.

Usage

1.Fixed anchor bolts are also called short anchor bolts, which are poured together with the foundation to fix equipment without strong vibration and impact.

2.Movable anchor bolts, also known as long anchor bolts, are detachable anchor bolts used to fix heavy machinery and equipment that are subject to strong vibration and impact.

3. Expansion anchor bolts are often used to fix simple equipment or auxiliary equipment that is standing still. The installation of expansion anchor anchor bolts should meet the following requirements: the distance from the bolt center to the edge of the foundation should not be less than 7 times the diameter of the expansion anchor anchor bolt; the foundation strength of the installation expansion anchor anchor bolt should not be less than 10MPa; there should be no cracks at the drilled hole, and pay attention to prevent it The drill bit collides with the steel bar and buried pipe in the foundation; the diameter and depth of the drill hole should match the expansion anchor bolt.

4. The bonding anchor bolt is a commonly used anchor bolt in recent years, and its method and requirements are the same as the anchor bolt. But pay attention to blowing the sundries in the hole when bonding, and not get damp. Anchor bolts edit aliases: stiffening anchor plate anchor bolts, welded anchor bolts, anchor claw anchor bolts, ribbed anchor bolts, anchor bolts, anchor screws, anchor wires, etc. It is specially designed to be buried in concrete foundation and used as the base for fixing various machines and equipment.

installation method

1. One-time burying method: When pouring concrete, bury the anchor bolts. When high towers are controlled by overturning, the anchor bolts should be embedded in one step.

2. Reserved hole method: the equipment is in place, the holes are cleaned, the anchor bolts are put into the holes, and the equipment is positioned and corrected, and then poured with non-shrinking fine stone concrete one level higher than the original foundation, and tamped and compacted . The distance from the center of the anchor bolt to the edge of the foundation should not be less than 2d (d is the diameter of the anchor bolt), and should not be less than 15mm (d≤20, should not be less than 10mm), and not less than half of the width of the anchor plate Add 50mm. When the above requirements cannot be met, appropriate measures should be taken to strengthen it. The diameter of the anchor bolts used for the structure should not be less than 20mm. When subjected to earthquakes, double nuts should be used for fixing, or other effective measures to prevent loosening should be adopted, but the anchoring length of the anchor bolts should be 5d longer than the non-seismic anchoring length.

Installation planning of anchor bolts

Treatment of the loosening of foundation bolts in the foundation. When the anchor bolts are tightened, the bolts may be pulled out. At this time, the bolts should be adjusted to the original position, and the foundation around the bolts should be shoveled out enough, and then welded on the bolts. Vertical and horizontal two U-shaped steel bars, and finally clean the pit with water and grouting. After the concrete has solidified to the design strength, tighten the live anchor bolts. The treatment method of live anchor bolt deviation is roughly the same as that of dead anchor bolts. Just pull out the anchor bolts for processing. If the bolt is too long, it can be cut off on the machine tool and threaded; if the bolt is too short, it can be extended by hot forging; if the position is not consistent, it can be corrected by bending.

Application industry

Suitable for all kinds of equipment fixing, steel structure foundation embedded parts, street lights, traffic signs, pumps, boiler installation, heavy equipment embedded fixing, etc.

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