Bolt Classification

Building anchors are divided into the following four categories according to their working principle and structure

2.1 Expansion anchors (referred to as expansion anchors) Expansion anchors use the relative displacement of the expansion cone and the sleeve to promote the expansion of the sleeve, and produce expansion and extrusion force with the concrete hole wall, and communicate with each other.

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The pull-out resistance is generated by the over-shearing friction effect, which realizes the anchoring of the fixed parts. Expansion anchors are divided into different sleeve expansion methods:

1) Torque control type

2) Displacement control type.

2.2 Reamed Anchor Bolt

The reaming type anchor bolts are used to ream the concrete at the bottom of the borehole, and use the mechanical interlocking between the concrete slope formed after the reaming and the anchor bolt expansion cone to achieve the anchoring of the structural fasteners. The anchoring force of the expanded hole anchor bolt is mainly caused by the direct pressure between the expansion cone and the concrete cone hole, not only the indirect expansion friction force, so the expansion and extrusion force is relatively small.

Reaming anchor bolts are divided into different reaming methods:

1) Pre-reamed ordinary anchor bolts: Pre-reamed holes with special drilling tools.

2) Self-reaming special anchor bolt: The anchor bolt comes with a tool, and the reaming hole is self-reaming during installation, and the reaming installation is completed at one time.

2.3 Bonded anchors

Adhesive anchor bolts are made by special chemical adhesives (anchor glue) to glue the screw and internally threaded pipes into the boreholes of the concrete base material. The adhesive and the anchor bolts and the adhesive and the concrete hole wall are glued and fixed. The bonding and key locking function of the steel plate can realize the anchoring of the fixed parts.

2.4 Chemical planting

Chemical planting is to cement and fix the ribbed steel bar in the borehole of the concrete base material through a chemical adhesive (anchor glue), and realize the anchoring of the ribbed steel bar through the effect of bonding and locking.