Gravel. Day 5 & 6.

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Wednesday Day 5. The heap outside the gate is shrinking fast. The surface of the gravel on the site is close to optimum. It just needs to be levelled and compacted.

The groundwater in the pier pipe hadn't moved overnight so I began dropping small, clean stones onto the water surface. It took a layer of only a couple of inches for it to remain dry and firm enough for me to stand on it. Though it still has a slight, spongy feel to it as I stamped about to level it.

I am now worried about losing depth of submergence of the base of the four pier timbers in compacted gravel. The concrete footings have considerable height which raises the bottom of the pier timbers considerably. Better, perhaps, to use a cross of heavy timbers. Bolted together with the pier timbers using galvanized [or better] stainless steel bolts. This would act as an anchor and resistive footing close to the bottom of the pipe.

This would immerse the base of the pier timbers to a much greater depth in heavy gravel for increased stability and damping. While simultaneously maximizing the height and weight of gravel above the timber anchor. Which probably amounts to the same thing. The cast concrete anchors would allow a greater splay of the pier timbers over pipe/gravel level. While the cross would force the pier timbers into a tighter bundle by the time they exited the top of the pipe.

Day 6 and all 10 cubic meters, or 20 tons of gravel, has been moved the 40 yards to the observatory site by wheelbarrow.  The next step is to obtain some concrete carport footings and set out the octagonal base around the concrete, pier pipe.

It seems I shall have to order another 2m³ of sand&gravel. The positions of the concrete footings [arrowed] would almost be out in mid air unless the bank is pushed out far more. I could bury the footings much deeper and have longer posts but it seems a weak solution. Particularly as that is the windward side during most storms. I can see the trailer getting considerable exercise but at least the gravel can be shoveled off right on the site. There is the alternative of having a cylindrical observatory building. Which would use more footings on the same radius for greater stability.

 Click on any image for an enlargement.

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