from where I sit the collapse is consistent with failure caused by slowly spreading "rot" in a concrete structure...e.g. the rebar slowly rusted away, and when the situation reached a tipping point noises started being heard and then BOOM, it failed in a limited area (as opposed to the whole building) and we have what we have where I sit is having been a carpenter for almost 40 years, made my share of things, torn down my share of things, seen my share of things failing...while I'm not an engineer I was raised by one and have more math learning than the vast majority of engineers so to me all the conspiracy theories are most likely just that...theories...I think if HAARP had been used the whole structure would have failed as opposed to the ocean facing side (you know, the side most directly affected by salt water)