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internal pressure for structural design

internal pressure for structural design

internal pressure for structural design

(OP)
hi,

i am designing a plated structure where client has specified to use

design internal pressure as 660mmWc at 67% yield strength.

as i am designing the Structure to LRFD - IS it Required to Increase the internal Pressure to 100% yield strength

i.e. 660/0.67 = 985 mm wc for Design of Structural Members?

thanks

RE: internal pressure for structural design

If I'm doing the conversion right, that's over 38 inches of water or 200 psf. This seems pretty high for ASD or LRFD, unless it's blast case or over a very small area with a small effective wind area combined with a hurricane level wind.

RE: internal pressure for structural design

Is it repeated loading where fatigue would be an issue?

RE: internal pressure for structural design

mmHg is not a unit I normally use, but it appears to me that it is considerably more than 38 inches of water or 200 psf. Is your client planning to detonate a bomb inside this structure?

660mm = 25.98" mercury or 352" H2O = 29.36' H2O = 1832 psf. Wow!

Edit: This is nonsense. See following posts. Please ignore this post!


BA

RE: internal pressure for structural design

It says 660mmWc, which I take as 660 mm water column, or about 135 psf.
It didn't indicate this was a building of any kind.

RE: internal pressure for structural design

Is this a pressurized process vessel? If it is, it's typical to do the design to the ASME standard, with structural loading being secondary to that using a methodology that can be linked to the ASME allowables or that separates the pressure load path from the load path supporting structure.

RE: internal pressure for structural design

Quote (JStephen)

It says 660mmWc, which I take as 660 mm water column, or about 135 psf.
It didn't indicate this was a building of any kind.
You are correct. I misread the Wc and assumed Hg. My bad!!!!

BA

RE: internal pressure for structural design

Why is client asking 0.67FY, where did this come from?

Client maybe using the old ASD-89 0.66FY bending for beam, which should have been 0.75FY bending for plate.

RE: internal pressure for structural design

Assuming the plated structure is not governed by any building codes, why use LRFD when the client specifies 0.67Fy?

RE: internal pressure for structural design

To directly address the question, though, I would make an equivalent load factor for this pressure load if I wanted to use that criteria and LRFD.

If the standard code check for ring tension would be 0.9Fy, I'd set the load factor such that (0.9Fy)/Factor=(2/3)*Fy. So your load factor would be 1.35.

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