For those interested in commentary on the collapse from engineers who are looking from the same vantage point as we are --outsiders-- here is a link to a forum that has an interesting thread. Some of the comments echo posters here, while others go into more depth. It will give insight into what the investigation will look for. So far no conspiracy theories.
http://www.eng-tips.com/viewthread.cfm?qid=436595
There are lots of questions regarding both the design of the bridge and the construction.