# Deformation of containers in the Tianjin explosion

1. Aug 18, 2015

### Anders Bruun

2. Aug 18, 2015

### Staff: Mentor

They look more melted from the heat of the fires than crushed by the explosions...

3. Aug 18, 2015

### Bystander

Very little burnt paint.

4. Aug 18, 2015

### Staff: Mentor

The shock wave from a large explosion applies an overpressure of hundreds of pounds per square inch as it passes by. That pressure makes for an enormous force when multiplied by the surface area of a shipping container - they'd be squashed flat as a penny on a railroad track if the force were applied for more than the few milliseconds it takes the shock wave to pass by.

Calculating blast effects accurately is difficult, but Google will find some useful models that will give numbers in the right order of magnitude.

5. Aug 18, 2015

### Bandit127

6. Aug 19, 2015

### SteamKing

Staff Emeritus
I don't know about "hundreds of pounds per square inch" of blast over pressure from a shock wave, at least not after it has propagated some distance from the explosion.

According to this:

https://en.wikipedia.org/wiki/Overpressure

and

http://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-125/125-ExplosionsandRefugeChambers.pdf

a much more modest over pressure of only 10 psi can blow off limbs and will severely damage, if not demolish, reinforced concrete structures.

7. Aug 19, 2015

### Anders Bruun

Maybe it would be possible to use the size of the crater to estimate it?

The crater from:

West Fertilizer Company explosion - Wikipedia, the free ...

was around 30 meters in diameter. The one from Tianjin is around 100 - 110 meters in diameter.

From what I understand the energy needed increases by r^5, so maybe that could be used ?