The Twin Towers had a lot of weld joints fail where there was no underlying mechanical connection between the beams and the columns. Plus the weld design and materials were questionable.
They failed because the invisible UV lasers from the MotherShip #19 cut those welds!
/s
We had a tank truck crash into a bridge overpass about Exit 112 on I-40 in NC about 18 years ago. The resultant fire caused the steel girders supporting the overpass to collapse.
It took about a year to completely repair the overpass.
I was a Census Taker in 1990. Because the driveway for one address had a chain across it, I had to walk to the top of a mountain to get the occupants to fill the questionnaire. Once there I discovered that there had been a house fire. Very large, fancy house. Later heard that the fire was “suspicious”. The thing I remember most was a steel “I” beam about 30 feet long with about an 18” high Web and 6” Flanges twisted like a piece of linguini.
From the heat of a residential fire.