3D Modeling

[James Hackerott]

Here we go ...


That's better.

Thanks for this Jerry. I was able to get the hotel to print it for me before almost finishing the measurements today. I hope to finish in the morning.

[Jerry Organ]

Thanks for this Jerry. I was able to get the hotel to print it for me before almost finishing the measurements today. I hope to finish in the morning.

Thank you, James. Whatever you can provide will help improve my bridge model. Sorry if some of the long measurements I asked for encountered impediments to the laser path and are not possible.

[James Hackerott]

Thank you, James. Whatever you can provide will help improve my bridge model. Sorry if some of the long measurements I asked for encountered impediments to the laser path and are not possible.

Just got home and unpacking stuff, and brain. I'm pretty happy about the results. I think the only measurement not (safely) made was the 90deg distance of the overpass, basically due to the freeways to the west being too close to line of site. Some longer distances are composed of smaller segments. Your revised drawing helped a lot with documenting measurements without having to try to describe them while measuring. More later in a day to two.

[Jerry Organ]

Just got home and unpacking stuff, and brain. I'm pretty happy about the results. I think the only measurement not (safely) made was the 90deg distance of the overpass, basically due to the freeways to the west being too close to line of site. Some longer distances are composed of smaller segments. Your revised drawing helped a lot with documenting measurements without having to try to describe them while measuring. More later in a day to two.

Sounds like quite an adventure. Glad you're safe and was able to make some use of that drawing.

[James Hackerott]

Triple UnderPass
Data collected from 20220927-30 with limited help from 2019 and 1999 sketches.


00   ?   No measurement due to safety concerns with freeway traffic too close to the line of sight.
01   124.5+/-1’
      Two stages- tripod mounted laser in front of column block 51.7”
      Tripod to corresponding column across the tracks- duplicate measurements 119,121’
02   47.7’    Measured in five segments from south face of column C to south face of column D.
02a   45.3’   Not indicated on the revised diagram. From midpoint of column D (½  of 88.5”) to north side of column E       (including the abutting post).
03   167’   Composed of  21 segments. Cumulative errors likely.
04   40.75”   Missed this measurement or failed to record it.  Computed #06 + #46 - #22
05   10”   Base of the beveled top (see notes about beveled surfaces in general)
06   39.6”   
07   5.75”
08   9 5/8”
09   7”
10   23”
11   8”   Missed measurement or failed to record it. I did measure that depth in my 2019 visit.
12   7”
13   9.5”
14   3 1/8”
15   1’ 11”
16   6”+1” bevel   Missed measurement or failed to record it. Data estimated from 2019, and 2022 data
17   1”   Bevel height
18   13”
19   15”
20   1”
21   ~2.5”
22   3”
23   7/8”+1” for bevel
24   5.75”+1” for bevel
25   2 7/8” +1” bevel
26   6” , 10 degree slope to apex (smart phone app)
27   15.5”
28   15”
29   15 3/8” (16” 2019 data)
30   29” (2’ 8.5” 2019 data)
31   42.5”  (48” 2019 data)
32   17”
33   37”
34   73”
35   8’ 9.2”
36   15’ 10”    2x #31 + #35 
37   Unable to reach high enough to extend the measure tape to the east edge
38   ?40-41”, Tape laid on top and extended to apparent edge. Photo’s show that edge as beginning of bevel.
39   ?33”, Tape edge probably did not reach the full length. (Photo), (3’ 10” 2019 measurement)
40   12”
41   12”
42   3” 6.7”
43   5’ 11.4”
44   40’ 4.7”
45   11’ 5.2”
46   3” + ~1.25” bevel?   (Photo 20220928_085633 ruler has 5mm dead space before 0”)
47   ~13-14”   Missed measurement or failed to record it. Estimate from photos compared with #05


Measurment key for Jerry’s Drawing


Measurment to what I think is the bridge bed. I’m not sure when the pedestrian sidewalk was added and if, or how, that might have covered the true bed (#04, #46).


Closeup of a typical edge bevel. I used 1” for my measurements but 1.25” might be closer, based on this image. I’d like to note that the bevels are everywhere! The devil is in the bevels for making close measurements as there are almost no sharp edges to be found. Were the edges originally sharp but eroded over 85 years?


Miscellaneous photos taken of the TUP top-side over three campaigns.
 https://drive.google.com/drive/folders/13Si6mnpR1aKiY7md6CYjvBsDEaXzkHFA?usp=sharing

[Jerry Organ]

Thanks James for such useful data. Now I can zoom in on my errors.

Some measurements I was surprisingly close to. I was off quite a bit on pedestal heights and some 200% in error on the thickness (east-to-west) of the banister. These are errors from my looking at photographs rather than measuring (which is a huge task to ask of somebody).

[James Hackerott]

Ever notice how the West and East slabs of the Triple Underpass Bridge differ in height?



A source tells me the streets slope downwards east-to-west inside the tunnel. I'm using a 1° slope in my model. I will have to merge this somehow with the 3° slope of the streets that run through the Plaza.

That's what works in my model. Might not work in yours.

With the laser I measured the heights above curb of the second column from the north (south side of sidewalk) on both the east and west sides. The height for the east column is 24’ 5” while the west column is 23’1”.  The difference of 16” over 124’ gives an average slope of -0.58 degrees in the westward direction.

I have a level app on my smartphone, but unfortunately only measures slopes as whole numbers without decimal precision. Readings for the eastern half were 1 degree and for the western half 0 degrees, for an average of -0.5 degree for the length of the underpass. Readings of the sidewalk approaching the underpass showed as 3 degrees.

Photos of the support columns from the inside shows a change of slope near the midpoint of the underpass.

[Jerry Organ]

With the laser I measured the heights above curb of the second column from the north (south side of sidewalk) on both the east and west sides. The height for the east column is 24’ 5” while the west column is 23’1”.  The difference of 16” over 124’ gives an average slope of -0.58 degrees in the westward direction.

I have a level app on my smartphone, but unfortunately only measures slopes as whole numbers without decimal precision. Readings for the eastern half were 1 degree and for the western half 0 degrees, for an average of -0.5 degree for the length of the underpass. Readings of the sidewalk approaching the underpass showed as 3 degrees.

Photos of the support columns from the inside shows a change of slope near the midpoint of the underpass.

Slope inflection. Never would have guessed. The roadway emerges on the west side of the bridge level. Makes sense now you've discovered it.

It's an amazing find and will save me a lot of 3D work. Thanks, James.