Official Explanations Cannot Explain Total Collapses of Any Type

These explanations cannot begin to explain any kind of total collapse.
(If damage due to impacts and fires were sufficient to cause some kind of collapse, it would have caused the tops to topple like trees, leaving the structures below the impact zones standing.)

The newly discovered ability of buildings to crush themselves is given the fancy name:
progressive total collapse.

A web search reveals most references to progressive collapse involve one or more of four cases:

• The WTC North Tower
• The WTC South Tower
• WTC Building 7
• The Murrah Federal Building in Oklahoma City (bombed in 1995).

Scientific method: A newly discovered phenomenon should be reproducible.

Take the THE PROGRESSIVE COLLAPSE CHALLENGE !

The explanations fail even in the abstract.
They are even less able to explain the features of the collapses revealed by the surviving photographic and video evidence.