Building the Pyramids Pt.1 Rise and fall pier?

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Interestingly, the pier key offers the potential for mounting rise and fall. The problem is not being able to fit anything [like a jack] between the pier and the obs. floor. Though that does not preclude a scissors, screw jack from being inserted into the pyramid itself below the key. It just needs the support for the jack to be fixed to the pyramid instead. The pyramid would need to be modified to allow sliding motion without any play [at all.] Something better than sawn wood rubbing against sawn wood would be desirable.

A rather quick drawing proved to be out of scale.
The pipes are only 3/4" larger than the 4"x4" pyramid posts.

A  typical car scissors jack provides about 8" of travel and the load would be relatively light compared with a car. A hand crank on a wheel in place of the jack's fiddly drive rod arrangement would be beneficial for regular use. I also have to brace the pyramid lower down to stop the timber adapter from rocking.

So I might as well consider rise and fall in the design. I have a long length of 120mm square [4.7"x4.7"] alloy tube with 5mm wall. That would be idea for the piston movement and it is quite close to the 4" timber I am using. Far closer than my drawing would indicate! There would be enough tube to provide a little over 60cm or 2' lengths for four, rise and fall , "pistons." Perhaps that's not really enough for stability when raised by 1/3 their length?

Having wasted weeks playing with different pier ideas it seems I am going off on another wild tangent. Perhaps I should go with the five posts adapter and return to "rise and fall" later. By then I should have had a chance to make some serious progress elsewhere. My first ideas are not always the best solution and they usually need time to mature into a better form.

As it was a hot and sunny 77F, it seemed like an good opportunity to make it feel even worse. So I dug holes and buried concrete footings to support the pyramid pier. Fortunately I was able to enjoy a little shade from the floorboards which I had left down on the joists upstairs.

Here, scraps of timber are used to locate the concrete footings at the correct angle in the excavation. Each off-cut was removed as I tamped self-compacting sand down firmly around the block with a batten.

I decided I would tilt the concrete blocks to follow the line of the posts. My fuzzy theory being that there would be a spreading force between the pyramid's feet. Getting the lean correct involved a mirror laid on top of the block. By sighting down the sloping post I could see my own reflection. The brackets provide fine, height adjustment by means of a 12mm screw. Which may become useful over time.

No doubt others will say that the forces on the pyramid's 'feet' are all vertical. Or will say the footings blocks are not necessary. They, like myself, have probably overlooked frost heave. We do suffer from annual, if short term, permafrost here. The double gates to the drive regularly droop in winter as the posts move. My feeling is that the footing blocks and brackets will provide solid, frost free location. Which will also save me having to add physical braces between the pyramid legs.

Only experience will tell if I was wrong to use the footing blocks and brackets. The disturbed sand and gravel will soon settle after  another day of my going mostly backwards and only a little forwards.

Click on any image for an enlargement.

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