ACI 318-14 Anchor Max Embedment & Min Spacing and Hilti Profis & Simpson Anchor Designer

[engjg]

With respect to typical cast-in headed anchor rods I note that Hiti Profis and Simpson Anchor Designer both limit you to a minimum spacing of 6 x diameter; it is my understanding this is the requirement for post-installed only and one can go down to a minimum 4xD for cast-in when evaluating per ACI 318-14 is this note correct?

Also I note Profis will not let you go more than 25 inch embedment; it was my understanding this was a limit in ACI 318-08 but was removed as of ACI 318-11 and beyond...is ACI 318-14 breakout equations not applicable to over 25 in embedment?

 

[TehMightyEngineer]

Going off of memory here. I believe you're correct about the first question; post-installed only and cast-in anchors can got down to 4 dia. bolt for the spacing. This is one reason I like using Powers (now Dewalt) software for cast-in anchor designs as it lets you compare cast-in to their post-installed options.

Regarding the 25" embedment, this may be a limit to their testing/ESR report. It's also a practical limit; good luck getting a drill bit long enough to go much beyond that unless you're coring it and have a lot of money for the equipment. Unfortunately Power's also limits you to 25", even for cast-in-place. Gotta break out those hand-calcs every once in a while.

Ian Riley, PE, SE
Professional Engineer (ME, NH, VT, CT, MA, FL) Structural Engineer (IL, HI)