Joint efficiency of water storage welded tank

[blawn]

Hi,

I'm currently evaluating a tank built in 1981,design code is AWWA D100-73 APP.C
I want to know the joint efficiency of the shell that was used during design.Shell plates are butt welded.I cant find any files of this old tank.
Any suggestion how to determine the joint efficiency?Thank you very much!

best regards,
blawn

 

[JStephen]

I believe Appendix C designs were always based on 100% joint efficiency.