MECHANICAL ANCHORS
OR EXPANSION SHELLS/UNITS

Regular Type (Left) & Bail Type (Right)
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Overview of Mechanically Anchors

There are many variations available in the market - from 2 leaf to those with multiple leaves i.e. more than four. Most manufacturers manufacture the various components from a cast material such as malleable iron. Duraset uses a unique forged 3 leaf design.

All anchors, although different in design, work on the same principle. The leaves have an outer surface which is roughened by serrations. This roughening increases the friction between the anchor and the surface of the borehole in which the anchor is inserted. The inner surfaces of the leaves have a taper which matches the taper on the corresponding surface of the expander plug.

On installation, the bolt or stud is torqued which then draws the expander plug down into the anchor. The leaves expand in a radial direction and securely engage the surface of the borehole. The anchor is now locked in position.

Applications

Regular Type Mechanical Anchors

• This type of anchor performs better in softer, less competent rocks, as higher initial setting loads are possible. They may however, also be used in the harder, more competent rock types.
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Bail Regular Type Mechanical Anchors

• This type of anchor is suitable for use in the harder, more competent rock types where only relatively low initial setting loads are required.
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How to Choose the Right Anchor For Your Needs

• Determine the ground type at the anchoring horizon of the anchor, (remember in hard measures, either bail type or regular type may be used and in softer measures, only the regular type should be used).
• Determine the diameter of the hole at the anchoring horizon.
• Select the appropriate anchor from the chart.
• Perform pull tests with these anchors to determine if the performance of the anchor meets your particular requirements.

Copyright © 2008 Duraset
Manufacturer of Rock Bolts, Studs & Mechanical Anchors