Hollowcore plank max point load

[cepe01]

How can I find the maximum allowable point load for hollow core plank load applied with a through bolt similar to the image attached? Assuming 8" thick 5,000 PSI slab, 10 ft long span.

The hollow core plank manual (

http://www.gateprecast.com/assets/files/PCI Hollow Core Slab Design Manual.pdf

) has a shear example on page 31 and 32 but it uses a PLF masonry load example.

Any help would be appreciated!

 

[Ingenuity]

You would need to know information about the plank first, like number, diameter and grade of strands, etc, then look at the section/plank capacity for shear and moment.

Then after you calculate these capacities and calc the allowable point load capacity, check your local effects/actions of the through-bolt, based upon the proposed plate washers, bolt dia etc.

Doubt you will find a cookie-cutter solution for this, so back to basics.

 

[briancpotter]

In addition to the issues Ingenuity mentioned, one thing you'll need to watch out for with point loads is longitudinal splitting of the plank. The pci hollowcore manual mentions this failure mode (see section 3-3), but doesn't actually give a method for checking it - it recommends relying on test data based on the specific slab system you're using. Unfortunately, in my experience, very few manufacturers actually have this available or bother to look at this particular failure mode.

How heavy are your heavy point loads?

 

[msquared48]

Is the precast panel manufacturer still in business?

If so, they may have some information and guidance, but as mentioned previously, this may be a pipe dream.

Mike McCann, PE, SE (WA)

 

[cepe01]

Thanks for the help. The point load 10,000 lbs on one bolt.

I called the manufacturer still waiting to hear back...

 

[BAretired]

I would be surprised if the manufacturer agrees that such a heavy load can be safely carried in the way you have indicated. Hollowcore planks have no transverse reinforcement, so a concentrated load must be distributed perpendicular to the span by tension in the concrete.

BA

 

[KootK]

I agree with BA. You've only got about 4500 lb punching shear capacity here, not including any uptick for precompressiom.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[rapt]

Agree with BA and Koot.

You would have make the top plate large enough and thick enough to transfer the load to the 2 "webs" rather than rely on the concrete to carry the load.

 

[KootK]

To clarify, my "punching shear" estimate above was actually based on distribution to the two adjacent webs and then one way shearing through those webs involving two shear crack planes per web.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.