Friday, March 02, 2007

Wall 2 Wall

The Grotto Wall, or Wall 1 as the engineers call it, is pretty well done and is already working to hold the hill back -- but that was the easy part. The second retaining wall, Wall 2 to our engineers (who are, we hope, much more skilled in coming up with a sturdy design than a clever name) is wider, taller and just to make things interesting, built 9 feet up in the air.

Here's the side plan of the house and the retaining walls. Wall 1 is pretty big, but not much of challenge since it is build on level ground.



Since this is way too easy for this crew, they now have to build a bigger wall, halfway up a steep hill, without causing the hill or the houses on either side collapse on them. Here's what that looks like in the plans:



If you take a peek at the dimensions of Wall 2, you will find that from bottom to tip, it is 14 feet tall. The base (or footing) is 8 feet wide by 2 feet deep, and the whole thing stretches 25 feet across the entire width of the property. This is not a easy wall to build anywhere, particularly up the side of a hill.

And here's what that looks like in real life. Wall 1 is the huge structure below, and up on that ledge that was just excavated, the footing for wall 2 will be poured today.



Here's a closer look at the footing, with all the rebar in place and waiting to receive a huge load of concrete.



What's odd about all of this is that this is the same hill that has been held in place with modest concrete wall and a few bricks for the last 60 years.



Why do we need this miniature version of Hoover Dam in our backyard? Did the laws of physics change recently? Is global warming causing a parallel increase in gravity and a decrease of angles of repose world wide? Or have we just been lucky all this time and our luck was bound to run out sooner or later?

We can think about this while the crew builds Wall 3, even higher up the hill, and to really make it a challenge, without using any heavy machinery.

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