There are numerous technical specifications that must be considered when using these anchors, including diameter, bolt diameter, and required hole size. The Double Expansion Anchor is a great fastener when working with soft masonry or base materials of questionable strength. The size of the anchor refers to the diameter of the machine bolt/screw used to expand this anchor. Once all of these factors have been determined, you can find the expected holding values in the technical information below.
To determine the length of machine bolt required, add the thickness of the material to be fastened plus the length of the single expansion anchor.
The forces on a Double Expansion 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 is 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.)|
|1/4”||1-3/8"||5 ft. lbs.||1/2"||532|
|5/16”||1-1/2"||7 ft. lbs.||5/8"||847|
|3/8”||2"||10 ft. lbs.||3/4"||1023|
|1/2”||2-1/2"||20 ft. lbs.||7/8"||1942|
|5/8”||2-5/8"||30 ft. lbs.||1"||3217|
|3/4”||3-15/16"||40 ft. lbs.||1-1/4"||4487|
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.