Are you asking about a uniform load or a single point load at midspan?

StructuralEng :

Do you have any deflection requirements?

StructuralEng :

Do you know the type of plywood (e.g. the stress grade level)?

StructuralEng :

Before we get started I’d like to point out that a Professional Engineer’s standard of care typically includes a site visit to assess field conditions and get an overall understanding of the structure. This can obviously not be accomplished through the internet. The information provided here is meant for informational purposes only (general sizing and budgeting) and is based on the information provided by you. Only vertical gravity loads will be considered, no lateral loads or analysis is looked at (this can be a big part of the design that will need to be considered). The information should be verified by a professional engineer who can visit the site to ensure that potentially important information has not been overlooked or omitted.

JACUSTOMER-djhs50ie- :

I am requesting a uniformed load for an elevated platform. The worker will be on their back on the platform. I am asking for a uniformed load. The plywood is 3/4 inch hard wood I would say it is 20 and not Pine. I would said a deflection no more than 1/4". I would say it is a least 25 pounds per sq inch per 1/4 " thinkness. There is 2x4 support under the plywood every 2 feet and 4x6 wood at each end of the 4 foot length.

StructuralEng :

Are the 2x4's running the running the 2' direction or the 4' direction?

JACUSTOMER-djhs50ie- :

The 2X4's are running the width of the platform, the 2 foot wide direction. And then 4X6 at the top and end of the 4 foot length.

StructuralEng :

So the face grain is perpendicular to the 2x4's?

StructuralEng :

So the plywood is spanning 2' to 2x4's, which are also spanning 2'?

JACUSTOMER-djhs50ie- :

1) Correct.

JACUSTOMER-djhs50ie- :

2) Correct

StructuralEng :

Great.

StructuralEng :

Give me a few minutes to run some numbers

JACUSTOMER-djhs50ie- :

Sound good.

StructuralEng :

Do you have a psf loading that you're looking for?

JACUSTOMER-djhs50ie- :

The total weight of the worker and tools is 160 pounds maybe 170 pounds at most on the platform. So say 160 pounds equal spaced over the length and width of the platform, so yes, I would like to know the psf figure.

StructuralEng :

The plywood won't have any problem with 75 psf

StructuralEng :

The 2x4's also won't have any problem with 75 psf to span the 2'

StructuralEng :

And they 4x6's are good for more than 75 psf spanning the 4'

StructuralEng :

If you could rate my answer, I would appreciate it.

StructuralEng :

I'll be happy to answer additional questions on the topic.

JACUSTOMER-djhs50ie- :

That is great. Can you shown me the math figures on how you came to that conclusion please?

JACUSTOMER-djhs50ie- :

I am rating you an excellent

StructuralEng :

I have spreadsheets set up.

StructuralEng :

But I can give you the general procedure

JACUSTOMER-djhs50ie- :

The genral procedure would be fantastic, thnak you.

StructuralEng :

I determine the moment, which is (w*l^2)/8

StructuralEng :

Then I determine the allowable moment, which is Fb*S

StructuralEng :

I set the two equal to each and solve for w

StructuralEng :

This will give the load in psf

JACUSTOMER-djhs50ie- :

Thank you so much. This is a big help.

StructuralEng :

No problem at all

StructuralEng :

Best of luck with your project

StructuralEng :

If you have any additional questions in the future, you can make sure I answer them by asking for Structuraleng to answer your question in the very beginning of your question.

If you could rate my answer, I would appreciate it. I’ll be happy to answer additional questions on the topic.

JACUSTOMER-djhs50ie- :

Thank you. XXXXX hit submit?

StructuralEng :

Yes

Customer:

Good glad you are back. Tried to rate you excellent and system went wonkie. Trying it again so ypou get paid.

StructuralEng :

Yep, I'm still here.

Customer:

Ok, good . Let me try this again.

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