Wedge anchors are manufactured out of different materials and plated differently for added rust resistance. The standard materials from which wedge anchors are manufactured are carbon steel, 303, 304 or 316 stainless steel. The carbon steel is plated with a zinc plated wedge anchor, hot-dipped galvanized or mechanically galvanized.
The wedge anchor is described in two parts, with the first number describing the diameter of the wedge anchor and the second number notating its length. For example, the description of a 5/8” diameter wedge anchor that is 8-1/2” long would be 5/8” x 8-1/2”.
Wedge anchors are available in nine diameters: 1/4”, 5/16”, 3/8”, 1/2”, 5/8”, 3/4”, 7/8”, 1” and 1-1/4”. Not all companies carry the full range of diameters. For example, Hilti, Inc does not have a 5/16” or a 7/8” kwik-bolt wedge anchor. However, Concrete Fastening Systems, Inc. has all diameters in all materials available in stock. The diameter of wedge anchor chosen is based on the holding values required and the hole diameter in the item being fastened.
Each diameter of wedge anchor comes in different lengths ranging from 1-3/4” length in the 1/4” diameter to 12” lengths in the 1/2”, 5/8”, 3/4”, 7/8”, 1” and 1-1/4” diameters. Adding the minimum embedment for the diameter of wedge anchor being used plus the thickness of the material, plus space for the nut and washer, determines the minimum length of wedge anchor used for any particular application.
As a rule of thumb, wedge anchors need to be spaced a minimum of 10 anchor diameters from each other. For example, a 1/2” wedge anchor needs to be at a minimum of 5” from each other.
Wedge anchors need to be placed no closer than 5 anchor diameters to an unsupported edge of concrete as a minimum. For example, the 1/2” diameter wedge anchor should be minimally 2-1/2” close to an unsupported edge from which it is installed.
The diameter of the hole that is drilled into the concrete is equal to the diameter of wedge anchor being installed; a 3/4” diameter wedge anchor requires a 3/4” hole.
If the wedge anchor is going to be inserted through the fixture and into the concrete with the fixture in place, then the hole in the fixture needs to be larger than the designated diameter of the wedge anchor being installed. Below is a chart showing the diameter of hole required for each diameter of wedge anchor. The fixture is referred to as the item that is being fastened to the concrete with the wedge anchor.
|Wedge Anchor Diameter||Hole in Fixture|
Drilling a hole in concrete for a wedge anchor must be done using a hammer drill set in the hammer and rotation mode. Hole size and shape are critical to obtaining holding values when installing wedge anchors. The only way to ensure this is through the use of a hammer drill.
The bit that must be used in the hammer drill must be carbide tipped and meet ANSI standards. The ANSI standard carbide bit will ensure proper tolerance between hole diameter and wedge anchor and diameter.
Concrete Fastening Systems, Inc. has a complete line of wedge anchors:
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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.