Plywood subfloor capacity with point loading 1

[lbeci]

I am trying to determine the maximum allowable point load that can be applied to center of the span of 23/32" thick 48/24 rated plywood subflooring. Floor joists spaced at 24" oc. I have searched the APA web site with no luck. Any suggestions where I could find design help?

 

[JAE]

To determine this you'd have to get the APA specification for design of plywood. Then you'd have to carefully analyze a point load on the plywood supported by spaced joinsts. The key would be to determine how much width to spread the point load over....or run a finite element analysis on it.

Then, with the determined shear and moment, use the APA allowable design values to verify capacity.

 

[miecz]

Try to find Research Report 135 published (a long time ago)by the American Plywood Association. Table 2.7 shows the results of tests for "Ultimate Load Stength of Plywood Under a Concentrated Load."

 

[FSS]

You can also call APA directly and talk to one of their engineers directly. They are usually helpful whenever I have called before.

And don't forget to post your results.

 

[lbeci]

I need to clarify my original request; I'm looking for some standardized tables to present to my client. I had questioned APA with this issue previously and was given the same response about the hand calcs. 'Jmiec' posted about research report 135, but I have not been able to locate this. Thanks all for your input.

 

[kbarnett]

If you can't find the table, try converting the rated uniform load to an equivalent point load at the center using bending moment equations set equal to each other. This will give you a good approximation. Then check for bearing based on the actual size of your "point" to make sure you don't need a bearing plate.

 

[miecz]

I only have the cover page and table 2.7. If APA isn't selling this report. Keep in mind that if APA isn't supporting this publication, then the information is questionable. That said, it's a very interesting table.

 

[lbeci]

Thanks for your help.