09 November 2011

[ayiti] Simple rubble math

Let's do some simple math related to rubble and (wo)man power.

The question is, how long would it take to process all the rubble necessary to build a single family home?

This wasn't the question I set out to answer today.  Instead, I just need to crush up some concrete debris some new friends of ours of Maple Hurst Builders gave me as part of thesis research.  The equation was actually

me + sledgehammer + large rubble + a good pair of safety glasses = crushed rubble


And certainly, the assumptions in this equation to answer the above question are that:
  1. This is done by purely human power, not mechanical means (potentially applicable to areas where machinery can't be reached)
  2. You have a woman doing the work (and a small one at that, given my own size)
  3. The measurement is for a rubble gabion house because this building method requires hand-sized pieces.  (A rubble crusher would be necessary to make the debris size any smaller.)
Anyways, when picking up the concrete debris with my trusted strongarm Marcus, we estimated that we hauled back about half a ton of rubble.  (As in, he carried most of it.  Thanks :)  )  I broke almost all of it into hand-sized pieces or smaller in about 1.25 hours.

If concrete weighs, on average, 150 pounds per cubic foot, then I crushed about 6 cubic feet, or 0.17 cubic meters (because we like meters in Haiti - and in all other parts of the world except for the US).  A rubble gabion house contains 46.3 cubic meters of rubble (calculations based on the Haven/Oxfam gabion pilot house in Clercine).

Therefore, it would take 341 hours or 6 weeks working 9 to 5 to crush enough rubble to make the house, let alone actually build it.

This number isn't particularly significant except to say that although I'm glad I can do this work, that is a LONG time.  At least I am not making a whole house for my thesis, nor am I doing this work alone because there are such people as men and more women, and such things as machines that can help get stuff done faster.  Oh, progress.

But indeed, women aren't afraid to sweat!

On another front, my mini material tests worked and didn't fall apart!  A preview for now:

[Note: no, the one on the right is NOT a big gray cake ... although it does look like frosting.  It's hiding a secret instead!]