Blast Calculation

[jpstruct]

Hi all. I have been a long time reader but have never posted until now. I am posting to see if anyone has any experience in blast calculations. I am in search of a good guideline either through the federal government or army core of engineers. If there are any other specifications out there (non government), I would certainly give those a look through as well. Any help or reference would be much appreciated.

The premise of the project would be to calculate a blast pressure based on a certain amount of TNT @ a certain distance for security purposes. Then design a wall & foundation to accommodate said loads. Thanks again.

 

[MiketheEngineer]

This has been asked a few times. Search the forums. And yes - I beleive there is a guideline - by either FEMA or the Army.

 

[cvg]

Here's the USACE publication:


Publication Number: EM 1110-2-3800
Title: Engineering and Design - Systematic Drilling and Blasting for Surface Excavations

 

[concretemasonry]

If this is for security purposes or even for other use, make sure you address the possibility of a blast from a non-typical or or unnatural cause.

The first building I designed was a 32x80' blast resistant structure with 12" thick reinforced masonry walls and 3 layer laminated blast resistant windows. Everything done according to the traditional and present standards including NASA and the USAF.

Three weeks after the completion, there was a failure where a blast collapsed the roof on top of many computers. The cause was from a bubble of hydrogen gas that was released nearby during the purging of tanks. Due to the light wind (or lack of), the bubble drifted over the building and somehow was set off by static electricity and caused a large pressure immediately over the building. At the time, it was possible to determine the cause quickly and terrorism was not a factor.

Today, with the terrorism and unique or creative acts conceived, the possibility of non-typical causes should be addressed and decided if these type of possibilities should be added to the design criteria. You never know what a kite or balloon can do if it was ignored on a structure that had security as one of the criteria.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[jpstruct]

All:

Thank you for your responses. After alot of research and scouring the web and picking the brains of some people with experience in this type of application I have found a few methods to determine blast forces.

1. US Army TM 5-1300 "STRUCTURES TO RESIST THE EFFECTS OF ACCIDENTAL EXPLOSIONS"
2. CONWEP Airblast Loading Model (Hyde, 1992)
3. DoD 6055.9-STD "DOD AMMUNITION AND EXPLOSIVES SAFETY STANDARDS"
4. FEMA 426 "Reference Manual to Mitigate Potential Terrorist Attacks Against Buildings"
5. FEMA 427 "Primer for Design of Commercial Buildings to Mitigate Terrorist Attacks"

As a side note I found TM 5-1300 the most helpful with calculating blast pressures. This is most likely becuase of the application of my problem which was essentially "X" amount of TNT @ "Y" distance away from a building. This allowed me to calculate the pressure on the barrier and windows of the structure (Not in my scope). Also, I was able to find a paper by A.M. Remennikov "A Review of Methods for Predicting Bomb Blast Effects on Buildings" that essentially confirmed what I had found elsewhere. It's in metric but if you do the conversions it works out in english units.

One more item I found that was helpful in wrapping your mind around the concept of bomb blast effects was the following power point.

http://gfsc.aero/en/Minutes of Meeting/Minutes of Meeting 2010 - Photos attached/Blast Loads.ppt

 

[rscassar]

I saw that the PCA has also recently released a publication considering aspects of progressive collapse and blast effects.

I have seen in some design reports that the design of specific structures does not consider progressive collapse or blast effects. It would be good to spell out that item early in the design stage. I have also seen in other design reports that the effects of column removal is considered and that secondary load paths have been provided for that scenario.

http://www.cement.org/bookstore/profile.asp?id=16945