Blast wall design 1

[walkac]

I have to design a 5 level parking garage for an US airport. The standoff distance between the terminal and garage is less than 300 ft. The only information I have is that, per the post 911 design guidelines, I have to design a blast wall between the garage and the terminal.

Can anyone direct me to the relevant blast design standards/manual,detailed parking standoff distance requirements. Any other info welcome..

Thanks.

Anirudh

 

[msp1]

Here is what the miliary requires. I don't know how it corresponds with airport design criteria, but i'm sure its similar.

http://www.acq.osd.mil/ie/irm/irm_library/UFC4_010_01.pdf

-mp

 

[jjeng2]

Will the balst wall be part of the parking structure or is it a seperate wall between? What are you constructing the garage with? There is an abundance of blast related stuff coming out all the time now and I may be able to point you somewhere is you can give me more inforamtion, especially on the type of construction. Also, if its steel, call AISC solutions center. If its concrete, call ACI. Next thurs and fri in NY ASCE is having a 2-day seminar/conference on security concerns for buildings. Looking at the schedule, I think you can get your questions answered there.

 

[walkac]

Dear jjeng2

Thanks for your promt reply. Here is the info you requested.

I don't want the blast wall to be part of the parking garage. If there are space constraints to install it independantly few feet away from the garage, then the wall could be a part of the garage. The garage is going to be Precast concrete, however the wall could be cast in place.

Further advice is helpful.

Thanks

Anirudh

 

[jjeng2]

I would check with the Precast Association to see if they have any guidelines and ACI to see what they have on cast-in-place walls. I know there are proprietary products to be used with masonry and concrete walls. There are also proprietary products to be used as stand alone walls. This is such an exploding(no pun intended) field of design, that i dont think you will have problems finding info. Id also check with FEMA and with the Parking Garage Association. Blast loading dynamics and mechanics has been very well defined for a long time. Most structural dynamics books have some info and I know there is a book just on blast loading. Check Amazon. That will help with analysis. Also check military publications.Up until recently they were the only one putting out info on this. Hinman Consulting Engineers in California has a lot of info on their website. Weidlinger in NY also does a lot of this type of design. Sorry I dont have anything more concrete, but I dont have time now to sort through my references. Hopefully I can point you in the right direction.

 

[bridgebuster]

Walkac,

A few things to consider:

What is the threat level? i.e. How large is the bomb; what type of explosive are you assuming; where will it be placed?

How much damage is the client willing to accept in the event of an explosion. This is something you need to discuss with your client. The more protection they want, the more the structure will cost.

A blast wall may or may not achieve the desired result. The location of the threat with respect to the blast wall is crucial. Depending on where the wall, the shock waves could go right over the wall. In that case the wall didn't serve any purpose.

Even with a blast wall, you need to consider the effects of broken glass/schrapnel from adjacent buildings injuring or killing people.

I think many clients don't fully understand what goes into this type of work. It's more than strucutral design. You might want to consult a firm that deals with this type of work.

 

[djbohn]

See NFPA 68: 'Venting of Deflagrations'for design of blast and vent walls.

 

[Lutfi]

mspetaga,

I know you intend well. I would not have posted the link for very obvious reasons.

My two cents worth.


Lutfi

http://www.cdeco.com

 

[bridgebuster]

Lufti,

I was surprised that the manual was still available on-line. However "Big Brother" must belong to this forum; the link no longer works.

 

[Lutfi]

By the way, the link still works! I know this document was not available to the public about a year and a half ago. I am really surprised that it is. Go figure.

Lutfi

http://www.cdeco.com

 

[theonlynamenottaken]

Ok, as "bridgebuster" said, this isn't a simple problem. First off you need to know what size charge and what charge material you're designing for. This should be provided by the client. Second, if the wall is meant to protect the entire terminal from the SHOCKWAVE then the wall has to be as tall as the terminal. It also would have to be close to the terminal, very close. If the wall is meant to protect the terminal from FRAGMENTS then it can be lower and closer to the deck... but you have to predict where the charge would be placed. ALSO, if a large enough charge was used it would just turn your wall into FRAGMENTS esentially providing shrapnel flying at the terminal. As far as the design goes you'll be calculating a triangular pulse load that has an initial pressure ~3-30 psi, and a duration ~10-25 ms before dropping linearly to zero (a reasonable simplification of a pretty complex shock loading). Gotta solve the dynamics problem to design the wall.

 

[walkac]

theonlynamenottaken,

Thanks for the advice. Can you direct me to a relevant manual for further details on the information you provided on blast loading.

Anirudh

 

[theonlynamenottaken]

TM5-1300 "Structures to Resist the Effects of Accidental Explosion" is probably the best resource. It is no longer available to the "general public", but you can request it from the DoD (I believe). With a brief description of your project they will gladly give it to you.

 

[eureka]

TM5-1300 is the Army designation. This publication also carries an Air Force designation AFR 88-22. It is available for down load at:

http://www.wpafb.af.mil/cpdc/pubs/AF/00088series.html

Look for AFP 88-22 it is in five parts. It is very large.