Maximum Load Test Results - Three Ladder Rack
independant lab tests performed by Anamet, Inc. (www.ftianamet.com)
U.S. Rack, Inc., 1-888-877-2257 |
Cargo carrying racks are commonly tested through static load testing. A commonly accepted industry-wide standard is that racks should be able to withstand at least 3 times the static load as the rated load they are assigned. This provides a 3 to 1 safety margin
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U.S. Rack products are tested at the Hayward, California facilities of Anamet, Inc. a respected independent materials testing laboratory.
Racks are tested in a machine that simultaneously measures vertical load applied to the rack as well as material deflection (bending). Since all materials bend a tiny amount when even the slightest load is applied, it is possible to measure the maximum strength of materials by measuring load and deflection.
In the graph below, the curved line represents the actual deflection of the rack as the load is increased. The straight line represents the theoretical deflection of the material. The upper point where the straight line and curved lines diverge is called the “limit of elastic deflection”. Beyond this point the material will fail and the rack will be permanently bent.
Anamet labs provided the below data.
THREE-LADDER TRUCK RACK, manufactured by U.S. Rack:
Load Rating for one receiver section of the rack and overall rack is 125 lbs.
Actual tested material failure point was about 625 lbs. about a 5 to 1 safety margin.
WARNING: This data is provided for information only. DO NOT ASSUME THAT BECAUSE LABORATORY TEST RESULTS INDICATE THIS PRODUCT WILL CARRY MORE THAN THE LOAD LIMIT THAT YOU CAN SAFELY EXCEED THIS LIMIT IN ACTUAL USE. STATIC LOADS ARE NOT THE SAME AS THE DYNAMIC LOADS OCCURING DURING USE. OTHER FACTORS, INCLUDING ADDITIONAL LOADING CAUSED BY BRAKING, ACCELERATING, TURNING AND TRAVELING ON SLOPED OR BUMPY SURFACES AMPLIFY FORCES IN ALL DIRECTIONS AND CAN LEAD TO MATERIAL FATIGUE OR FAILURE IF PUBLISHED LOAD LIMITS ARE EXCEEDED. DO NOT EXCEED LOAD RATING.
Load Rating for the horizontal crossbar of one section of this rack is 75 lbs.
Actual tested material failure point was about 425 lbs., greater than a 5 to 1 safety margin.
TEST APPARATUS WITH THREE LADDER RACK DURING TEST
 
TESTING LOWER PORTIONS OF RACK TESTING HORIZONTAL CROSSBAR
BENT THREE-LADDER RACK SHOWN AFTER TESTING AT OVER 610 LBS.
NOTE: The structural from of this rack is shown on the left. The lower receiver section of the rack is not shown but proved to be stronger than the structural frame.
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