Where is the project located? Dominion Bridge fabricated joists in Nova Scotia starting in 1964 under the name Robb Engineering. Robb joists have a history of failure due to poor joint design (or lack thereof) and almost non-existent quality control. There is lots of info out there on identifying, inspecting, and remediating Robb joists. The defective joists were used extensively in Atlantic Canada from around 1964-1985.
DB may have started that way... but in 1965, DB was also fabricating OWSJ in their Winnipeg operation... I worked on the joist line as a student. Quality control was well in place at that time and their OWSJs were used throughout western Canada. They were well respected at the time. I no longer have my copies of their joist catalogues, but has asked some of my colleagues to see if they have copies that I can scan.
dik, I think it was a local issue. Dominion Bridge bought Robb Engineering in 1964 and I think the poor fabrication practices were isolated in the Amherst, NS shop. Reading about the history of these joists is interesting/scary. There were two roof failures in Newfoundland in the 90's the kicked off the investigation - it was revealed that the manufactures were aware of the issue since the late 70's. Government owned buildings were inspected and remediated as required back when the problem was first discovered, but in the Atlantic region you still come across some undiscovered Robb joist in privately owned buildings.
22D10 is a 22" deep joist with a number 10 top chord. Although the catalogue I have doesn't have information on the top chord size. It does have span tables.
I've attached the first two pages that cover 22"
