As far as the image goes I'm not going to read anything into it. The hole could have been created by a collapse such as the entire section on the front of the building. May not even be a hole but just blackened wall.
jpete wrote:Except they reportedly rebuild this section after Oklahoma City.
Actually I posted a link to the renovation, this only covers what they did on the inside walls and the date indicates a few years after the attack. On a side note this article states there was no reinforcing on the limestone perimeter wall. The original rebar was set too close to the surface so it was corroding and cracking the concrete. What they did was jackhammer back into the concrete, applied some kind of anti corrosion treatment and poured the wall back out to adequately cover the rebar. This article also states 3,500 psi for the original concrete however I read another article stating it was only 2,500. The renovation at least for the inside walls appears to only be fixing the surface areas that are cracking. http://www.structuremag.org/article.aspx?articleID=1
As you can see the walls don't appear to be that thick.