ACI 318-11, Appendix D, D.3.3.4.3, Upset Threads and Stretch Length

[cpiedra23]

I've been studying the referenced ACI code section, specifically (a)3 and a(5), and am having a hard time understanding what exactly 'stretch lengths' are, how it's detailed, the benefits of its use. Also, I can't find a clear definition/explanation of what 'upset threads' are. I've tried reading the commentary and it's helped, but was wondering if anyone knew of a publication elaborating on this, or provide elaboration on this thread.

Thanks

 

[wannabeSE]

For stretch length, have you looked at figure RD.1.3 in ACI 318-11? The definition of stretch length is below this figure on page 421. Upset threads have threaded sections with a larger diameter than the anchor rods diameter (look at the "Old Style A36 Tie Rod" picture in table at the bottom of the page at

http://www.williamsform.com/Marine_Tie_Back_Tie_Rods/tie_back_tie_rods.html)