As the hearing continues the focus is on the type of epoxy used in the ceiling panels that collapsed in the Big Dig tunnel last summer.
Following a presentation outlining the fundamentals of epoxy. The conversation has now turned to the difference between "fast set" epoxies and standard epoxy. The epoxy used in the tunnel in question was a fast set epoxy. And the question now is whether in effect the wrong "glue" was used and was this information availalbe to the designers, project managers and suppliers. It’s a question of the load values in terms of the type of epoxy used, along with the long-term characteristics of fast set epoxy and the safety value factor of this type of adhesive in this type of structure. Was the epoxy used appropriate for the loads it was expected to hold?