Installing the Lower Half of Concrete and Poly Shielding

This page shows the installation of the concrete and poly shielding around the lower half of the HF assembly. Getting the lowest blocks in requires the use of some type of forklift-like fixturing because the concrete and poly cannot be lowered straight down through the cradle. I was forced in this direction because the concrete cannot be installed earlier during cradle fabrication. Installing concrete blocks during construction of the cradle would deny access to the bolts that attach the wedges to the shielding plates, so that is infeasible.

Notice that the cradle has an extra steel plate (light blue) on the mid-plane surface at the bottom. I put this feature in because there are two alternative ways to mount the concrete blocks to the vertical cradle plates. In one scenario, the first block is installed as shown by bolting it with short bolts to the upstream two cradle plates from the outside surface of each plate. Once this is done, the downstream block cannot be assembled the same way because the upstream block blocks bolt access to the middle cradle plate. To allow the downstream block to be assembled, another plate was added to the cradle to bolt the downstream block on. This means that the rest of the downstream blocks are bolted from the outside to the downstream cradle plate, but at the other end of these blocks they must be bolted to the concrete block below them. They cannot be bolted to the middle cradle plate because all the upstream blocks interfere with this.

A second scenario that I like much better which eliminates this problem is to cast pipes into the concrete blocks that run parallel to the beam axis. Then, the middle cradle plate can be tapped with enough holes so that long threaded rods can be passed through the upstream and downstream cradle plates, through the pipes in the concrete blocks, and threaded into the tapped holes in the middle cradle plate. The tapped holes for the upstream and downstream blocks would be alternated so they don't collide with one another. This would make the concrete blocks rest on the threaded rods. It should be possible to support any of the concrete blocks on just two rods each.

It is assumed that the poly plates are bolted to anchors in the outer surfaces of the concrete blocks. Only the bottom most poly plates need to be attached to their concrete blocks before the concrete blocks are installed in the cradle. (There isn't enough room below them to bolt them on after the concrete block is in place.)

You are welcome to download any of the images. If they are used for other than private viewing, credit to Bartoszek Engineering would be appreciated.

A view from the back before any concrete is installed, 167K

Installing the upstream bottom block and its poly, 169K

Downstream bottom block installation, 169K

The second row of concrete blocks installed, 159K

I'm skipping steps here because the sequence should be obvious now. These blocks also have poly segments bolted on to their bottom surfaces prior to block installation.

Attaching the third row of concrete blocks, 163K

The poly is also attached to the second row of blocks at this point.

Attaching the poly to the third row of concrete blocks, 156K

This is all that can be done with the lower cradle assembly at this point.

Forward to assembling the top cradle of shielding

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