Information on older concrete design codes and products (e.g. concrete pan joists) is presented in:
CRSI Design Manual, Concrete Reinforcing Steel Institute, 1959. (www.archive.org)
If you are looking for older or newer versions, many are available on secondary markets but none appear to be in the public domain. The status of the 1959 is perhaps in question as well, as archive.org can be a bit enthusiastic with their contents. The document isn't valid for current design, but for checking an existing design it has it's uses. Perhaps even "fair use".
On this forum, KootK has indicated they have "all" of them.
https://www.eng-tips.com/viewthread.cfm?qid=402664
I have one from around 1984, if you need a specific page, use the feedback on this FAQ and it will send me an email. For other versions, look up the user name in question, see where they've posted recently (if they are still active) and try to catch them by responding to one of those threads, as there's no mechanism to send a direct message to a user here.
