Wedge anchors can only be used in solid concrete. They cannot be used in brick, block, and mortar joints. While natural base materials such as stone and granite may be solid, they are inconsistent and their holding values have not been tested. The design of the wedge anchor is such that the holding values are created at one certain point. The expansion clip requires solid contact with the base material and expands over a very short area. Attempts at using the wedge anchor in materials other than concrete will result in problems that are described below:
Before drilling and installing a wedge anchor, the concrete must have had a minimum of 28 days to set properly. Therefore, do not install a wedge anchor into green concrete (the term describing concrete that is less than 28 days old). Installing a wedge anchor before the 28 days have passed will negatively affect the holding values.
The item being attached affects the choice of fastener because of the variance in its thickness and weight. Also, a specific type of fastener with a certain diameter and embedment depth must be used when specified by an engineer.
The wedge anchor is the only mechanical expansion anchor used in different environments that are available in four types based on plating or the steel from which it is manufactured. It is very important to select the correct type of wedge anchor to ensure that it does not rust, which would result in deteriorating holding values.
The wedge anchor is designed to fasten static loads only. A static load is a load that does not move. Wedge anchors should not be used for applications where the load will vibrate or be subjected to shock loads. An example of a vibratory load would be a flagpole, and an example of a shock loading application would be a dock bumper.
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As with any anchoring project, it is important to keep safety in mind and follow instructions carefully. Always remember to wear safety goggles, handle all tools with extra care and follow all technical specifications. This article is meant to serve only as a basic explanation of concrete fasteners. Always refer to manufacturer's instructions or consult a contracting expert during any anchoring project.