Friday, August 24, 2007

Fortress Update

This is almost getting to be routine – one day after another of great progress!

As of this morning, we are getting dangerously close to being ready for the final concrete pour. The forms are completely finished (although they're going to do some extra bracing on the interior section this morning), the bottom web of rebar is complete, and the top web of rebar is well underway. We need a few more pieces of rebar, and my contractor is supposed to bring them this morning before 11 am. Of course, he's been saying he'd bring them every single day this week, sometimes promising them on multiple occasions in a single day – but they haven't shown up yet.

In an earlier fortress update, I promised I'd share my load calculations. The interior portion of the forms (the only worrisome part) has to hold up a chunk of concrete that is 16' by 16' by 11.25" (average). This works out to 39,120 pounds – 20 tons. A total of 45 4x4s will be holding that weight up, evenly distributed between them. The loading on each 4x4 is therefore 869 lbs, and that is well within their strength limits – depending on the variety and quality of the wood, a 4x4 should be able to easily handle 4 to 10 times that loading. So no worries on that score…

It's been interesting to watch how David approaches the construction of the rebar. Basically he's building the two webs directly on top of the form, and will worry about securing them at the proper level as the very last step. By doing this, he makes it much easier to put the bars into place and secure them with twisted wire – he's free to walk all over them without having to worry about falling through. He's described how the two webs will be lifted into the proper position – that process sounds quite interesting, and I'm looking forward to seeing it happen – hopefully, later today!

If that so-and-so contractor of mine actually makes it here with the rebar…

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