Creep in epoxy anchors

A large customer of ours will not permit the use of any drilled epoxy anchors. They believe the event that occurred in the Big Dig was witness of a creep phenomenon that can not be predicted for controlled for and therefore poses a long term risk of failure that is unacceptable to them. I would like to demonstrate to them that proper design using Hilti products is a safe reliable means of anchoring to concrete. Can you help me convince them by providing documentation and/treatises that discuss this matter? I AM SURE I am not the first person to ask you this. TY