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“If it is a 4-Ton Lifting Pin Anchor (dog bone) it must lift up 4-tons (8,000 lbs.)”

It is a common misconception within the industry that we would like to address in today’s blog. The tonnage in the title of the anchors generally refers to the lifting capability of the anchor itself. However, depending on the PSI of the concrete during lifting, the usage capacity of the anchor can vary.

For example, when properly imbedded and lifted, a 10” 8-Ton ALP Lifting Pin Anchor (LPA8T10G) has an in-concrete capacity of 16,000 lbs in FULLY cured concrete and an Ultimate Mechanical Capacity of 64,000 lbs. Ultimate Mechanical Capacity is the total weight that the anchor can hold in mechanical testing of the steel.

Even though the in-concrete capacity is 8 tons in fully cured concrete, it will vary with greener concrete. For example, in 2,000 PSI concrete the in-concrete capacity for this anchor goes down to 14,110 lbs, and at 1,500 PSI it goes to 12,220 lbs (see attached chart for additional examples).

It’s also important to keep in mind that all of these in-concrete capacities have a 4:1 SWL (Safe Working Load). This means that the capacity rating for this anchor is 1/4 of the failure point during testing. A 4:1 SWL is standard with all embedded lifting anchors. Because of impact loads and instances in which one of the anchors in a precast piece takes more weight than another, this safety ratio is essential for safe lifting. However, it is highly recommended that, during handling, precast products are transported on even, smooth ground to eliminate impact loads. In addition, rigging and lift planning should be done by a qualified engineer to ensure proper use of the anchors and other lifting hardware. If you have any questions regarding proper rigging, please contact us at 800-332-7090.