Whole width of the core survives the initial collapse
We can identify all core columns in rows 500 and 600 with certainty by using the publicly available video. Both rows of columns completely survived the initial collapse at least 51 stories high. The 2 corner columns, 501 and 508 temporarily survived to the 77th floor.
First we positively identify the west side columns, then the east side columns.
Identification of west side columns
A gif of different viewpoints giving a 3-D glimpse of column pairs 501-6-0, 502-602 and 503-603:
501 is the tallest column of all on the right and 504 is the tall one bending to the right.
We can see how 504 bends to the right and hits 503 in this gif:
which places the two columns in the same row.
We see 504 lean and hit 503 clearest in this video:
Columns 504, tall and leaning, and column 501 can serve as easily identifiable landmarks in most all video and photos of the core remnant. We know that columns 501 to 504 mark the boundaries of the the west half of the core. We also know that all columns east of 504 must be from the east side of the core. In the image the east and west sides of the core are distinguishable just by locating columns 501 and 504
CCs 501 and 504 are the tallest columns and easily identifiable. We can identify the east side columns as all those to the right of CC 504.
Identification of east side columns
Using CC 504 as a reference line, we catch a vivid glance of many core columns to the left of CC 504., both standing and falling away. This is the east side of the core, column pairs 505-605 to 508-608.
This excellent gif lets us see the east side column pairs falling away. Use column 504 as a reference line to see where the east side begins
Video that shows the east side of the core momentarily
This video shows the east side of the core moving and falling independently of the west side:
and images from the video allows us to see the west and east sides of the core and identify the east side columns, shown in this gif:
This shows the full width of the core. Identification of the full width of the core (8 column pairs total) allows us to conclude that the tallest column on the far west is indeed column 501, confirming the original claim.
Identification of 700-800 core column pair in the core remnant
The distance between 700-800 columns is significantly less than that of the 500-600 separation as a diagram with the spacing dimensions shows:
From the southwest two column pairs forming rectangles with different height to width (h to w) ratios are visible:
The location of the photographer is known to be about 22 degrees from the building's east-west axis. This means:
width we see = actual width x cos(22) (roughly), while cos(22) =.93
Distance between 500-600 = 15.25 ft
between 600-700 = 20.5 ft
between 700-800 = 10.3 ft
distance between 704-805 = 9.5 ft
floor height about 12.5 ft
For the blue rectangle w>h while for the red one h>w giving h to w ratios matching the 500-600 row for the blue rectangle and 700-800 for the red one.
Created on 10/10/2010 12:22 AM by admin
Updated on 04/27/2011 01:07 AM by admin