like these, which would indicate rot. >> since we didn't find them present, then we were fairly comfortable that there was no appreciable deterioration of the piles contributing to the collapse. >> all that remained were three concrete piers. when investigators looked more closely, they discovered that the steel plates used to connect the bridge to the concrete were displaced 48 inches out of alignment. corley also examined the bolts that attached the metal plates to the concrete. >> those attachments were poorly maintained. in several cases, the holes that were supposed to have bolts through them didn't have anything recognizable in them. when we took the material out that was in those holes, we found that it was rust. >> when the sunset limited was