J bolts 3

[eit09]

I have been asked to use J bolts for anchor design. Are there any design aids or examples out there? I've done my web searches and there is not much out there on J bolt design. The client specified the material, diameter, and 90 deg hook length (which happens to be 6db vs the normal 12db). Not sure how to reduce the capacity due to the shorter hook length? Does anyone have any references they could point me to?

 

[Lion06]

ACI App. D, the pullout equation for a hooked oblt is in D.5.3.5 (Eq D-16).

I would recommend against hooked bolts though. AISC recommends against them in any situation where tension is applied.

 

[Lion06]

ACI App. D, the pullout equation for a hooked bolt is in D.5.3.5 (Eq D-16).

I would recommend against hooked bolts though. AISC recommends against them in any situation where tension is applied.

 

[JedClampett]

I've got a hankering for some Doublemint gum.

 

[eit09]

Do you know where AISC states this? I see that in D-16 thanks. Have you seen anyting about using less than 12db for the hook length?

 

[Lion06]

AISC stated that in DG #1, which is not available right now (it's being re-written).

DG #1 also used to have minimum embedments (usually some number of diameters), but App. D doesn't recognize a minimum, just whatever it needs to be to work. That being said, we use a minimum of 9" for a 3/4" anchor rod. If I end up with a bigger anchor then it typically needs a much deeper embedment anyway.

 

[PMR06]

AISC 13th, pg 14-10, states that hooked anchor rods should only be used for compression columns, but can be used for tension due to erection loads.

 

[Bagman2524]

I believe there is the possibilty of the J section of the J-hook straightening out causes the bolt to lose a significant portion of its' capacity. Which is why AISC recommends against using them.