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Blast Resistant RC structure design?

Blast Resistant RC structure design?

Blast Resistant RC structure design?

(OP)
dear All,

I need to design blast resistant RC wall for air compressor unit, there is not any flamable liquid or gases nearby that may trigger fire another explosion, can you give me an entrypoint on which code that I need to fullfill.

Regards,

RE: Blast Resistant RC structure design?

Where's your project Joe?

Hopefully your threat catches the attention of CELinOttowa's attention. He's a bit of a blast wiz.

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.

RE: Blast Resistant RC structure design?

(OP)
It's in Turkey, searching through forums for relevant thread I found that bit of an out-dated TM5-1300 is the suggested code. I'd like to know is it compulsory to have the wall all around the perimeter of unit or do I have to provide relase section (which I believe is generally roof) ?

I know that this topic on itself worth thomes of books, but at least I need to provide on what premise I'm designing and I must meet base design criteria. Talking from experience as I worked as CM there wasn't anything additional we do (nor the designer foresee ) for the air compressors units other than steel facade.

Regards,

RE: Blast Resistant RC structure design?

Probably the most popular reference I've seen used (besides TM5-1300) is 'Design of Blast-Resistant Buildings in Petrochemical Facilities' by ASCE. One important thing you need to get from the client right off the bat is what kind of damage is he willing to take? Something that will survive the explosion undamaged or something that can be damaged (and replaced later)? A lot of times, they initially say the former but then you let them know the costs and that changes real fast.

RE: Blast Resistant RC structure design?

UFC 3-340-02 has replaced 5-1300. If this is a contained explosion, BlastX can be used but I would suggest getting assistance using this program going forward.

RE: Blast Resistant RC structure design?

(OP)
Dear All,

Thank you all for the valuable inputs and entrypoints, pointing out that UFC 3-340-02 is valid for blast design criteria was really helpfull. Runing a quick eye through the chapters, one thing is still obscure to me. After finding location oriented parameters such as l/L, h/H, L/H, Za and reading the Average Peak Reflected Pressure (Pr) from figures, should I apply that load as uniform load to structure or is there any other process I have go through?

If I should stick with applying the Pr directly to structure then its quite conservative IMHO, one can easily achieve in close-in range 1000psi values for (Pr). My structure is: "L" shaped wall, I can't even think how it can sustain the stability checks e.g. overturn, sliding etc.. with such a heavy load,

Your comments will be appreciated,

Regards,

RE: Blast Resistant RC structure design?

If you are getting loads that are not feasible to handle.......you may need blast panels or a redesign (possibly with a more flexible structure or a different layout [or setback distance] to reduce pressure). But again, you have to get a feel for what your options are and ask the client what is acceptable to them.

RE: Blast Resistant RC structure design?

(OP)
Asking the client which is more feasible is of course something that I'll do, but before that I need to be sure that the method I'm following ( forming the l/L, h/H, L/H, Za parameters and reading the graphical forms) using to find the Pr value is correct and I'm not missing any crucial and vital step. Can you confirm that its the legitimate way of doing it ?

Regards,

RE: Blast Resistant RC structure design?

I don't have anything on me right now but I have a reference at home....will look at it tonight.

For the record: will this blast occur in a enclosed room or just adjacent to a wall in a open area? What's the equivalent poundage in TNT?

RE: Blast Resistant RC structure design?

Oh and by the way: what's the standoff distance?

RE: Blast Resistant RC structure design?

(OP)
The blast wall I'm trying to design will be after construction phase cast in-situ RC, in case of steam geyser explosion. So the blast will occur at the enclosed room, L=20m (wall Length); H=5m (wall height ) , l = 4m ( standoff distance of geyser) ; h = 1.8m height position of geyser. But I really don't know the equivalent poundage in TNT.

Regards,

RE: Blast Resistant RC structure design?

A pressure wave from blast is different than a normally-applied wind load. I.e. the load is not a simple pressure wave pushing radially out from the source. If your compressor is in an enclosure, the enclosure would see a reflected pressure on the facing side, have downward pressure from the blast "bubble" as it passes over, and the away-side of the enclodure would also have inward directed force as the wave of high pressure passes beyond. If you have no roof, the compressor would be subject to significant blast pressure directed downward from above.

The nature and duration of the blast are important to the structure and its response. An exploding gas acts differently than something like TNT. Determining the pressure and duration of your kind of blast is probably quite a specialized function. I'm not sure what you mean by "geyser".

To apply the side-on (or worse, the reflected) pressure as a static force is very, very conservative. Depending on the nature of the blast and the response, most structures absorb the blast energy and see an effect much less than the static equivalent. You will need to consult with a specialist if you really want to get a best guess as to your structure's response.

RE: Blast Resistant RC structure design?

Without an equivalent poundage of TNT, I cannot figure pressures with what I have (sorry). Also, a enclosed room is a different animal compared to a wall at a certain standoff distance. The mechanics of what happens gets a bit more complicated. You may want to get a consultant/specialist involved at this point.

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