Where did the bolts go?
Note, in the first three images below, the modular wall structural units, made up of three vertical pieces and three horizontal pieces.
The vertical pieces are approximately 36-foot lengths of perimeter columns, each column 14" square in section.
The wide horizontal pieces, or spandrels, serve to both tie the columns together and to furnish an anchoring area for the floor trusses.
Each spandrel is about a meter from top to bottom, and on its inside face received all the floor trusses, which were welded and bolted to the spandrels. The spandrels were welded and bolted to the column modular units, which were bolted together end to end, every three floors, from bottom to top of each tower.
The end junctions, where three connected columns (i.e. one of the modular units) were bolted end to end to the column units directly above and below it. These bolted column ends proceeded in a leapfrog fashion, as can be seen in the first three images.
Once the trusses of all the floors had been set between the core columns and the perimeter columns, the end-to-end bolts "became a safety factor", so to speak: in other words, they became superfluous to the necessary stability and the strength of the towers.
There were three sets (one per floor) of meter-deep steel trusses attached to each one of the modular units, and these trusses were welded and bolted to the heavy steel columns in the core, which were welded end to end from the ground to the top of the building, creating 47 single columns each about 1300 feet in length- literally a single piece, since welds (properly done) are as strong, or stronger, than the steel being welded.
The end-to-end bolts could have been removed, quite easily, with hand or light power tools, via the access holes adjacent to every bolted connection.
If the bolts had been removed, the towers would not have moved a millimeter in any direction as a result. The strength of the floor systems every twelve feet completely prevented any lateral movement whatsoever of the exterior columns making up the "perimeter column" walls (i.e. the four outside walls of each tower).
If the end-to-end column bolts were removed, then the destruction of the core and the floor trusses would have left the four outside walls of the towers doing an impossibly precarious balancing act. can be demonstrated, for example, by attempting, or better yet just imagining an attempt to stack bamboo chopsticks end to end twenty or thirty or a hundred feet high, without the whole mess collapsing at the very first joint.
It would be enough to send a person back to building houses of cards, which are much easier to construct than chopsticks on end.
Of course, even if the end bolts in the Twin Towers' perimeter column walls had all been in place, a laterally unsupported, thin "straw" of steel a quarter mile long would be as floppy as a length of sewing thread; and at "ground zero" there would be many more long sections of many modules, still bolted together end to end.
Many post-collapse photos show this phenomenon clearly, where large areas of the modular units are still connected to the others above, below, and to both sides of it: that is, those large, jagged parts of the outer walls which were left standing after the collapse.
Although very unstable, these tall remnants of the perimeter walls stood for some time after the disaster, until eventually brought down by the ground zero construction workers.
So, if all the bolts were in place, it would not have made any significant difference to the total destruction, except that the modular units, which were originally trucked in on flatbed trucks, couldn't as easily be trucked back out, but would have be be disconnected at the bolted joints (or, more likely, cut with oxyacetylene torches) in order to haul them all to the ships which had been hired to take all the Twin Towers steel to the other side of the world and melt it down before too many people could get a good look at it.
Removing all the bolts- if that was done, and the photo evidence shouts it- would have saved time and money and would have been good demolition technique, more efficient than trying to cut some two hundred and forty quarter-mile long steel columns, all still bolted end to end, and terribly tangled together in a mountain of giant steel spaghetti.
The photos below show that in almost all cases that can be seen in ground zero photographs (to the best of my knowledge) the end bolts are absent, and there is no distortion of the end plates even when the steel a boot or two from the ends is bent or twisted.
The only sensible conclusion is that all those thousands of bolts (I'll leave it to someone else to calculate how many thousands) were removed before September 11.
If not, then where did they go?
In almost all the photos showing the ends of the modular units, the 14" x 14" end plates are undisturbed, with no sign of bending, rupture, heat, explosives, or any mechanical force sufficient to tear bolts (approx. 1" in diameter) in pieces and make them disappear so that they are never found.
No, they must have been removed, to facilitate the total destruction, and to make the cleanup more efficient.
It is highly unlikely that they were never installed during construction of the Twin Towers. Until the floor systems were all connected, the bolts were essential. The bolts would have definitely been placed in any case, simply for the sake of alignment- but after the Towers came down, hardly any bolts, of so many thousand, can be seen. m