Hanging from Precast Double Tee Stem
Hanging from Precast Double Tee Stem
(OP)
I am thru bolting the stem of a precast prestressed double tee to support a hanger. I am trying to calculate the shear breakout force of the bolt but am wondering if the bottom of the tee goes into tension and thus reduces the allowable shear.
Can I use 2 x sqrt of F'c per 11.4.1 for the min. allowable?
How high up on the the stem would you recommend the bolts to be? I know this depends upon the breakout force....
Can I use 2 x sqrt of F'c per 11.4.1 for the min. allowable?
How high up on the the stem would you recommend the bolts to be? I know this depends upon the breakout force....






RE: Hanging from Precast Double Tee Stem
RE: Hanging from Precast Double Tee Stem
First, the location of the through bolt will need to be above the strands and any longitudinal reinforcement. This must be coordinated with the precaster (this is not an option and if you don't do it you may need to replace the tee or worse). You will probably find that you will need to through bolt about 12" from the bottom of the stem. At this point you will probably not need to concern yourself with breakout, but if you do...
consider that you are now above the main structural reinforcement of the precast element and it is hard to believe that any load that can be sustained by the tee would cause failure at that location.
RE: Hanging from Precast Double Tee Stem
RE: Hanging from Precast Double Tee Stem
What are you hanging that requires a through bolt through the stem? Usually any piping and conduits can be managed with an expansion bolt. Even with expansion bolts I still prefer to limit their connections to the flange.
RE: Hanging from Precast Double Tee Stem
RE: Hanging from Precast Double Tee Stem