A couple of days after the cement was poured, it was time to remove the scaffolding that had held the walls plumb and in place. This is the ICF frost wall and foundation for the inner staircase.
As we stripped off the scaffolding and kick plates that had been on the footings to hold the bottom of the ICF forms in place, we would lean them up against the wall so we could then pass them outside.
Here is a good view of the plywood and 2×6 framework I constructed to support the central column that will be the telescope pier, prior to form removal, as well as the two 12 inch sonotubes that will carry the load from teleposts supporting the second floor to the telepost pads buried 8 feet below grade.
Pouring a 30 foot tall column for the telescope pier cannot be done in one pour (at least not with the budget we have to work with), so instead, it will be done in 3 sections. This pour was for the first 10 feet of the column. The 3/4″ rebar around the edges will help tie the next pour of concrete into the column, and the surface was left intentionally rough to provide more surface area at the joint. It will still be a cold joint; that’s unavoidable, but hopefully it will still be rigid enough. After all, the telescope, mount, and equipment sitting on top will “only” weigh about 700 pounds, and the 30 inch square column should be more than capable of supporting hundreds of tons. So the column is definitely overkill, but the huge mass of the concrete, which won’t be in physical contact with the observatory building itself, should serve to provide a very stable platform for the telescope.
After the plywood forms were stripped away, the cement of the telescope pier itself was revealed. I was quite happy with how the consolidation of the concrete turned out.
Here, we are pretty much done stripping all of the supports and scaffolding. All that’s left is one small section of scaffolding on the west wall that we left in place to help transfer materials out of the excavation, as well as the blue scaffolding we used to pour the telescope pier, and the little bridges I had constructed to get in and out of the interior of the frost walls. Those, of course, would all be removed before we started backfilling.
And here is a photo of the construction site and its location, in relation to our house and yard.
