http://en.wikipedia.org/wiki/J._E._R._Carpenter
Saturday, March 8, 2014
Friday, March 7, 2014
Monday, March 3, 2014
Brooklyn Bridge
Found a wonderful image with fairly clear dimensions this morning.
This gave me fairly definite numbers for the base. The second tier above the base starts at 19'6 above the waterline.
Sunday, March 2, 2014
Hezkhel and the Parallax Conundrum
My friend Hezkhel, an accomplished engineer and fine singer, took a look at my parallax dilemma and confirmed some things that I had suspected.
I probably don't have enough known dimensions to accurately solve the problem, but I can extrapolate the known dimensions I have to make some fairly accurate guesses. He suggested that this is a totally acceptable way of approaching this problem and that engineers often just use their good judgement to solve problems.
He also hinted at using inner right triangles to minimize any errors in a potential guessing game.
I probably don't have enough known dimensions to accurately solve the problem, but I can extrapolate the known dimensions I have to make some fairly accurate guesses. He suggested that this is a totally acceptable way of approaching this problem and that engineers often just use their good judgement to solve problems.
He also hinted at using inner right triangles to minimize any errors in a potential guessing game.
Brooklyn Bridge
Blueprints lie.
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.
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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