Jun 202007

Now that the flatwork is done, our crews are building the retaining walls. The formula is the same, first black drain mat, then PrePrufe membrane is secured to the shoring wall, and it’s taped and sealed to form a water-tight barrier. Bituthene sealer is used around the Nelson studs and tiebacks that protrude through the membrane. Then a double rebar cage is assembled.


I finally got a picture of the rebar delivery truck. Even though you can’t see it from this angle, the single-seat cab is less than 4 feet wide! I think the chassis is a 1940’s Chevy, with a Ford cab. This is the steel that will go into the lower part of the walls, and the shelves.


Here is the site today, after a few days of work. The rebar cage is progressing steadily, and the waterproofing will be finished tomorrow. The plan is to build a form behind the rebar across the front of the shelf (where the guy in the blue shirt is standing), then apply shotcrete up to several feet above the shelf.

The concrete shelf in the back wall has to encase the tiebacks, which you can see sticking out of the wall just above the rebar cage. This will form a solid beam across the back of the wall, making it strong enough to apparently withstand nuclear attack as well as earthquakes. So Brent and his crew will pour concrete onto the back shelf, almost 3 feet thick, to encompass the tiebacks, and the formed shotcrete wall in the front will hold the concrete in place. They are doing the same thing for the shelf on the left, although the concrete will only be about 10” thick because there are no tiebacks going through it.

This is one of the places were we are paying for the excavation mistakes of the original contractor. The back shelf was not originally designed to be 3 feet thick, but we have to make it that thick to include the tiebacks.


Here you can see the rebar construction more clearly. The double cage of bars is connected together as it wraps sideways over the shelf on the left of the foundation, and back vertically up the wall. The cage will be wired together the same way over the shelf on the back wall also. The orange things are plastic caps over the ends of the rebar, to keep the crew from being injured.

Notice the remains of the construction stairway that the original contractor built up the left side of the property, above the wall? The stair now terminates at the wing wall, in mid-air. It’s pretty useless now.

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