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The excavation continued today with a piece of rented equipment added to the backhoe and dozer. After many attempts to remove some very hard rock over the last few days with only very minor success, we rented a hydraulic rock breaker, basically a large jack hammer operated like a backhoe except it is on the end of a boom.
Here's how it works. Cover your ears.
Scintillating, eh?
Scott worked with this machine all day long and well after dark. First he drilled on the limestone. Then, while the rubble was being scraped away with the dozer or backhoe, he cleaned up another part of the excavated wall. Earlier in the day, the walls were marked with spray paint to show where they needed to be trimmed. The paint marks looked like cave drawings.
He switched between the wall and the limestone, back and forth, while someone else was cleaning up behind him.
This continued until about 7:30, almost two hours past sunset, since the rented machine needs to be returned tomorrow morning. About 6:15, it became clear that we would be there all night and still not remove all of the limestone.
I took a chance that my structural engineer might be in his office and called him to discuss the situation. Luckily, he was there.
I suggested that we could stop chipping away rock when we got it down to the level of the top of the footing to be poured. Then we could taper the footing when it came to the rock and continue it on the other side. He agreed that that would work if we connected the footings on either side of the rock with arched reinforcing bars embedded into each footing. These would be tied to a few bars drilled into the rock and the rebar in the wall when it is added. Additionally, the footing could be widened on the wall's outside. His only concern is that we take extra care to seal the connection between the rock and the concrete to prevent moisture seepage.
There are more pictures on my web album: http://picasaweb.google.com/ed.paynter/NewHomeConstruction#
