Revisions to Brooklyn Bridge

After some time spent doing "knuckles" and train stuff, and preparing for solo guitar work, back to the Bridge.
David McCullough's book specifies the size of each tower at top (276'6" level) to be 136x53.
My work is done at 135'10.5"x 59'. Not sure how I arrived at those numbers,(ed. I got 135'10.5" from Roebling's original drawings) but I'm willing to take David at his word.
(ed.No idea where 59' came from....52'10.5" is on Roebling's drawings.. )
There appear to be some basic differences between Roebling's original and the executed plan.
For instance, Roebling differentiates between the NY and Brooklyn towers in basic dimensions, but McCullough's stats say they are the same.

I'm inclined to leave level 261 3 thru 273 3 alone for now. A lot went into them and they look good.

Perhaps its time to review the whole drawing (since its been done in fits and starts for the last couple of months) and get some definite numbers for each level and see what elements in the drawing are either mistakes or nonessential......


z_Level 270 3 actual
 shows the diagonals from 261 3 to 270 3. At 270 3 there is an overhang and the overhang is denoted by
z_Level 270 3
April 19 temp
shows how I took the dimensions from level 141 6 and basically copied them to 270 3 for the overhang dimensions

z_Base to 12 ft
is just what it says.....level 0' to 12'
z_Level 1 renamed z_Level 19'6 to 59'6
is 19'6" to 59'6"
z_Level 2
is 67' to 103' 6"
z_Level 3 renamed z_Level 114'
is a flat plane at 114'
z_Level 4 renamed z_Level 114' to 116'
is 114' to 116'

Looks like a left out a lot of stuff on or about the roadway level......Then started meshing again using, maybe, the peaks of the arches for reference....Who knows....
That's what happens when you are your own project manager and the work is somewhat unorganized.


In the weeds!

The roadway should start at 120'4", according to my numbers.
The numbers in McCulloughs book just don't add up.....

"Height of roadway at towers 119'
Height of arches above roadway 117'
Height of towers above roadway 159'"

They just don't work....

Height of arches above roadway 117', appears to agree with other sources.....

Some Progress

Level 271'3 to 272'3

This level appears to be a repeat of the level 141'6"with some modifications, ie the setback in the middle sections which I estimated to be 2'5 1/4".

Back to the Bridge

After much hours of recording today, I decided to take a mental break and resume work on the NY tower of the Brooklyn Bridge. Haven't worked on it for a while, so remembering where I was at was a little confusing at first. Scanned some more drawings yesterday that gives me more accurate placement of the saddles.
Sort of stuck at the apx 274'3" level, right below the absolute 276'6" level. Sort of the widest portion of the tiptop of the tower.
I have reasonably accurate numbers for this  (274'3") level so I will work on it for a while.

Blender units discussion

http://www.katsbits.com/tutorials/blender/metric-imperial-units.php


As usual, like a lot of things, this turned out to be a simple and profound solution.
This really helps with difficult edits in Blender. Draftsight is so much more precise.

By simply changing SCALE under IMPERIAL in Blender to 0.0254 I'm able to cross platform between Blender and Draftsight.

I was having an issue editing the roadway to be one continuous span from anchorage to anchorage, but this technique solved it pretty quickly.

(addendum. Apparently it makes no difference. I'm having a hard time wrapping my mind around this. Perhaps it has been a long day and my brain is not functioning in an optimum way.... Whatever. As Scarlett says, I will think about it tomorrow.)

Some Stats

The full width of the bridge floor is 85' according to "The Great East River Bridge"-the Brooklyn Museum.

The road is 2 degrees from the anchorage to the middle span.

Brooklyn Bridge progress

Images

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.

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.

The Colosseum in Rome

Unlike earlier Greek theatres that were built into hillsides, the Colosseum is an entirely free-standing structure. It derives its basic exterior and interior architecture from that of two Roman theatres back to back. It is elliptical in plan and is 189 meters (615 ft / 640 Roman feet) long, and 156 meters (510 ft / 528 Roman feet) wide, with a base area of 6 acres (24,000 m²). The height of the outer wall is 48 meters (157 ft / 165 Roman feet). The perimeter originally measured 545 meters (1,788 ft / 1,835 Roman feet). The central arena is an oval 87 m (287 ft) long and 55 m (180 ft) wide, surrounded by a wall 5 m (15 ft) high, above which rose tiers of seating.

The Brooklyn Bridge Manhattan elevation is 276.5' x 140' x 59'