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RE: Blast Resistant Building Design for Blast Containment

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You might also want to take a look at ASCE's new "Structural Design for
Physical Security: State of Practice".  While it appears to be aimed more
at terrorist type bombing attacks, I would suspect that it would address
some of the issues with regards to blast pressures.  You can order it thru
ASCE at 800-548-2723.  It is $18 for ASCE or SEI members and $24 for
non-members.

Scott

At 12:09 PM 01/03/2000 -0500, you wrote:
>Bill,
>
>I checked with some of the engineers in our office who have experience in
>design of blast resistant test cells regarding using tilt up precast
>concrete construction.  Their opinion is that it may be technically
>feasible but the panel thicknesses are going to be well beyond standard
>tilt up panels which affects costs and as you and others mentioned the
>connection details are real challenge.  Also, shear design requires lacing
>reinforcement when the scaled distance Z < 3 which further complicates the
>design.
>
>I am not aware of any 'cook' book approach that can be used to calculate
>the blast loads on the access door behind the labryinth walls due to the
>complex reflection effects that take place.  There are some PC based codes
>available for predicting the blast loads from government sources that you
>may be able to apply.  You have to check with your contracting officer to
>see if you have access to these sources.  Basically, the test cell would be
>divided into multiple 'analytical' compartments connected by vent areas but
>there are limiting parameters (such as length to effective diameter ratio,
>... etc.) that may rule out the use of these codes.  You may also need to
>consider the mass of the vented panels.  We are using computational fluid
>dynamics (CFD) methods for these problems now with an in-house PC based
>program.  Otherwise, you will probably find yourself making conservative
>assumptions.
>
>Walt Sawruk
>EQE International, Inc.
>Shillington, PA
>email: ws(--nospam--at)eqe.com
>
>
>At 10:05 AM 28-12-1999 -0600, you wrote:
>>Wanted to make sure someone was listening before I drug out the story.
>>
>>We've got a "test cell" building to design. Four test cells, three small
>>(0.7 kg TNT equivalent) and one large (1.4 kg TNT equivalent). They are
>>adjacent to a lab space that is expected to be occupied.
>>
>>The outward facing walls we will make "blast vented" so that the impulse
>>from a blast will be limited (at least that's my understanding of how this
>>works). There will be a wall stood off from this wall to shield property and
>>living organisms from any debris that might be blown outward.
>>
>>The common wall with the occupied lab space is my concern, however.
>>
>>An additional complication, at least the way I see it, is that there is a
>>"blast lock" in one corner of each cell, such that someone can go through a
>>door from the lab to the lock, then turn 90 degrees to go through a blast
>>door into a cell. Each cell is thus an irregular "ell" shape, to accomodate
>>the lock.
>>
>>The client wants to use all "tilt-up" construction (which I don't see as
>>viable for the test cell portion of the building). Is this possible, in your
>>opinion?
>>
>>Also, how much help is the "blast vent" wall panel array? How much can it be
>>expected to mitigate the blast impulse overpressure acting on the other
>>walls?
>>
>>How about the wall joints? The only other deal like this that I've ever done
>>we used non-reentrant corners. This has 'em all over the place.
>>
>>I wonder if some sort of "composite" R/C wall, maybe with a sandwiched layer
>>of something like styrofoam (deformational) or lead shot (mass) would help
>>to cushion the blow?
>>
>>Finally, how would you approach this analytically? Is there a simplified
>>analysis that you could use? We have the Army TM 5-1300 manual(s), but I
>>haven't perused them enough to tell if they give guidance in this regard.
>>
>>Any thoughts you'd have along these lines would be much appreciated.
>>
>>Thanks and regards.
>>
>
>