I did notice that. After having tied rebar together for years it seamed strange I couldn't make out any in the pic. It seems as the years have gone by they have required the rebar to closer and tighter together and more of it. Also on some of the larger jobs I was involved in, (one of which was about the same size as the museum they required a separate Storm sewer based on the square footage of the building and water run off. You could have parked 3 cars in the storm sewer, it was huge. This was built about 1996 in washington state. I am not sure what year the museum was built, but I assume it was up to local code.