Having established the top and bottom points of the arches, let the midpoint of the arches begin at 24'10.5" from the midpoint. This is not a known distance but fairly matches the blueprint.
Then the width of each arch should be offset 16'10.5" from the midpoint of the arches. This is a known distance from the blueprint.
This creates a 16' middle column(between the arches). This is not a known dimension.
This also creates 28'3" maximum outer column width on the upper portion of the bridge. This is not a known dimension, but looks like a good number.
The circles that will create the arches are specified to be 46' diameter intersecting (at least) at the peak of the arches. I created the leftmost circle using the 3pt method and determined I would have to make its center Y at 201'8.75", up from the 201'4" working baseline of the arch base. This let me extrapolate all other circles using linear dimensioning to line them up.
This meant I would have to create 4.75" lines from the baseline to lower intersection of the circles to create a seamless arch.
(Oh heck, I just left them alone...)
Soooo.
I got the tolerance to 1/16". Not bad for Sunday night after a long weekend.
Not sure how or if to fix it...
Anyways, it's late now and that's enough work for one week. At least I got a few things right.
That's one thing about drafting. You can always fix things later.
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