F 1554 Headed Anchors vs. Threaded Rod
F 1554 Headed Anchors vs. Threaded Rod
(OP)
As best I can tell, ASTM F 1554 and ACI 318 Appendix D don't make a strength distinctions between headed anchors and the "equivalent" threaded rods. However, I have read several places online that threaded rods are 10-15% weaker than headed bolts, which makes perfect sense to me given the physical differences between the two. Here is one reference: http://www.portlandbolt.com/faqs/headed-anchor-bol...
Q. Are there any anchor bolt experts out there who can [1] tell me what I may have missed in ASTM F 1554 and/or ACI 318 on this subject, [2] tell me if threaded rod is truly equivalent to headed anchors or should be derated, and [3] give me any other words of wisdom on this subject?
In my 33 years of experience in civil engineering, including some light structural, I have only ever used headed anchors and L- and J-anchors. I have no practical experience with threaded rods for anchoring. Unfortunately, I have a contractor who can only get about 2/3 of the thirty-two 1" diameter, Grade 55, headed anchors he needs for my project in a timely fashion. On the other hand, he can get more than enough threaded rod of the same type by tomorrow. Per my client's request, I am looking at alternatives.
If I assume that threaded rods are 15% weaker than the equivalent headed bolt, my design goes from working to not working. If I go up to 1-1/8" in diameter, my design works again. Unfortunately, the contractor's vendor doesn't have enough of the larger size. L- and J-anchor are out because they don't meet the concrete pull-out criteria until I get to 1-1/2", which is too big for our application.
I love it when questions like this come up at the end of the day.
Q. Are there any anchor bolt experts out there who can [1] tell me what I may have missed in ASTM F 1554 and/or ACI 318 on this subject, [2] tell me if threaded rod is truly equivalent to headed anchors or should be derated, and [3] give me any other words of wisdom on this subject?
In my 33 years of experience in civil engineering, including some light structural, I have only ever used headed anchors and L- and J-anchors. I have no practical experience with threaded rods for anchoring. Unfortunately, I have a contractor who can only get about 2/3 of the thirty-two 1" diameter, Grade 55, headed anchors he needs for my project in a timely fashion. On the other hand, he can get more than enough threaded rod of the same type by tomorrow. Per my client's request, I am looking at alternatives.
If I assume that threaded rods are 15% weaker than the equivalent headed bolt, my design goes from working to not working. If I go up to 1-1/8" in diameter, my design works again. Unfortunately, the contractor's vendor doesn't have enough of the larger size. L- and J-anchor are out because they don't meet the concrete pull-out criteria until I get to 1-1/2", which is too big for our application.
I love it when questions like this come up at the end of the day.
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