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Diaphragm check

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BAGW

Structural
Joined
Jul 15, 2015
Messages
392
Location
US
Hi,

I have a diaphragm force of 420kips (ASD) being resisted in a slab whose diaphragm capacity is 3500lbs/ft. 420kips is resulting is a diaphragm force of 4500lbs/ft. So the diaphragm does not work. What are the alternatives to resist this diaphragm force with out increasing the slab thickness? Is adding reinforcement an option? If reinforcement is added, do I need to size the reinforcement for full 420 kips of capacity or just the difference (1000lbs/ft)?

Any other way of resisting the diaphragm force?

The force 420kips is resulting form the ASCE Eq 12.10-2 and not from analysis. The analysis force is just 210kips.

Thanks
 
Assuming you increased the concrete strength, how much of an increase would you need? 2,500 psi or so? Not sure how feasible that is in your situation, but it’s my first thought.
 
Look into this equation from ACI 318-14, which allows you to utilize the distributed slab reinforcement for diaphragm shear strength:

Screenshot_2022-02-20_134857_bzpjab.png
 
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