The EERC was built in the mid 70′s. I think it was completed in 1977, just after I graduated. Half of Hotchkiss Hall was torn down to make way for construction and the other half after it was completed. A false wall was installed at the open end. It looks like the picture was taken as the first half of Hotchkiss was being torn down to make way.
One floor of the new building was built without windows for the Seaman Mineral Museum.
Regarding the question what the EERC building replaced.
When I started at Tech in 1953, I think it might have had no formal name or was just maybe called “East Engineering.”
But sometime during my time at Tech, 1953-57, I believe that it was redesignated as “Hotchkiss Engineering” or something similar.
Ed Miller, ‘57
I believe that EERC went up on previously private land, former site of JT Reeder house. No solid research to back that notion…