# Wood Structural Panels (Diaphragms)



## Mithrandir918 (Feb 17, 2018)

Wood Structural Panels consist of plywood, OSB and composite panels and are recommend thought NOT required per NDS SDPWS for use on wood diaphragms.  The tables for unit shears provided in the SDPWS appear to be only given for WSP sheathing (either for Structural I or basically all other grades).  So what happens if you have a gypsum board or particleboard sheathing, where do we get design values for this?


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## User1 (Feb 17, 2018)

Mithrandir918 said:


> Wood Structural Panels consist of plywood, OSB and composite panels and are recommend thought NOT required per NDS SDPWS for use on wood diaphragms.  The tables for unit shears provided in the SDPWS appear to be only given for WSP sheathing (either for Structural I or basically all other grades).  So what happens if you have a gypsum board or particleboard sheathing, where do we get design values for this?


Look at the tables again. I don't have my sdpws on hand but I'm sure I've found gyp values. Maybe more tables on different pages or a special line. Can't remember exactly because I never use gyp for anything but 100plf for existing buildings in practice 

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## Mithrandir918 (Feb 18, 2018)

There is values for shear walls but not for diaphragms in the SDPWS using gypsum board


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## kevo_55 (Feb 18, 2018)

Look in the IBC.......


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## Mithrandir918 (Feb 18, 2018)

IBC is for stapled diaphragms though my problem was for nailed.


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## PowerStroke79_PE (Feb 18, 2018)

Mithrandir918 said:


> IBC is for stapled diaphragms though my problem was for nailed.


Does this help.... 

I've never liked considering the shear value of gypsum board over a diaphragm or wall. I even had issues using it as sheathing for 4.4.1.2 c or other considerations that allow us to consider the system continuously braced because of the gypsum sheathing. However, I suppose I am being conservative by it.  

In case this image is helpful, I think it is, I am including the link to the PDF. There is more research out there on gypsum board over stud walls with gypsum being Cement base taped and other samples not. The results are interesting, but It still doesn't make it comfortable for me to include it in my calcs. I wouldn't like to use particle board for that matter and there is enough data for it that could be helpful in some designs. 

http://www.icc-es.org/reports/pdf_files/ESR-1338.pdf


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