The diagram clearly provides the designations of the core columns and the floor at which their cross-section changed from box-like to H-shaped (or "wide flange", WF).
Having established that NIST did not misrepresent core column cross-sections, we can now focus on column size. The same NIST report shows this illustration on page 11:
The photograph below shows clearly the exact point of transition from box column to H-shaped column:
The core columns of course were not mutually independent: they were linked by horizontal members known as core channels, shown below in some examples of their failure modes:
Let us also check how the much-maligned final report from NIST describes the various types of core column, so we can see whether the conspiracy theorists' allegation of a NIST attempt to minimize the structural strength of the cores holds water. These are the two paragraphs which give the specifications of the two types of column used in the WTC core:
Accordingly, we know the location and main mechanical production and installation characteristics for every single component in the design, in addition to the name of its supplier and its shipping batch code.
Essentially, the Twin Towers were a huge puzzle in which the builders had to ensure on-time delivery of the unique parts intended for the assembly process.In view of these findings, I believe there is no way one can claim that NIST attempted to provide misleading information.
Those who make such allegations are probably poorly informed or lack the technical skills needed to comprehend the wording of specialist reports.
- Stresses -
One can gain some insight into the stresses to which the core colums were subjected from these photographs of some of the columns recovered and retained for technical inspections:
- Go to: ENGLISH SECTION