Before installing strike anchors, certain technical specifications must be considered to ensure the correct size and length are used. Considerations include ultimate holding values, minimum embedment, the spacing between anchors and minimum edge distance. They are available in diameters ranging from 1/4" to 3/4” and with lengths up to 6”. Strike anchors are made from carbon steel and plated with a yellow dichromate zinc plating. Strike anchors should be used in solid concrete only.
Length: To determine the length required, add the thickness of the material to be fastened, plus minimum embedment, plus the thickness of the nut and washer. The sum of these three items equals the minimum length.
Spacing: The forces on a strike anchor are transferred to the material in which it is installed. If the anchors are installed too close together, it can cause an interaction of the forces, thus reducing the holding power. As a rule of thumb, the expansion anchor industry has established a minimum standard of ten (10) anchor diameters for spacing between anchors and five (5) anchor diameters from an unsupported edge. When vibration or sudden impact are part of the load conditions, the spacing should be increased.
Technical Information: Ultimate Load Values in 2000 PSI Concrete
|Size||Minimum Embedment||Max. Torque||Drill Bit||Pull-Out (lbs.)||Shear (lbs.)|
|1/4”||1”||5 ft. lbs.||1/4”||675||1200|
|5/16”||1-1/4”||7 ft. lbs.||5/16”||1050||2250|
|3/8”||1-1/2”||10 ft. lbs.||3/8”||1650||2550|
|1/2”||2”||20 ft. lbs.||1/2”||2700||5400|
|5/8”||2-1/2”||30 ft. lbs.||5/8”||4050||4950|
|3/4”||3”||40 ft. lbs.||3/4”||5625||10125|
Values shown are average ultimate values and are offered only as a guide and are not guaranteed. A safety factor of 4:1 or 25% is generally accepted as a safe working load. Reference should be made to applicable codes for the specific working ratio.