That such a sound could communicate such and such a meaning? It's as odd as the word "odd" is. I started this thread dealing with one aspect of the mystery, but everything is a mystery. Only someone in construction can appreciate some of the really strange things that happen. Sometimes a knowledge of materials science helps give insight, but sometimes things are so strange that I just tell people its a mystery. I built a ceramic lap pool for a lady five years ago. Chrome rails were mounted around the edge of the pool held in place with locking sleeves. We had to hammer the rails into the sockets before tightening the locking bolts. A few weeks ago one end of one rail exploded in the middle of the night--literally blew out of the eight-inch thick concrete embedded stainless steel sleeve taking a hunk of ceramic with it. I know of no physical process that could do this although there must be one. An employee pushed the rail back into the sleeve with no pressure, but this morning I could not move the thing despite bashing on it with rubber mallets with a hydraulic jack and two men using a long lever. I finally gave up and told the lady it was a mystery. LOL. She asked if it could happen again, and I said, "sure, but hopefully it won't." IMO the whole thing was rather ODD.
