Hello,
I am trying to design a connection for secondary steel supported on concrete ground beams (report attached). Steel needs to be 120 minutes fire rated, so connection needs the same. I have no problem with ULS design, but Fire design has more than 1000% utilization ratio. I think that steel is a problem, not a concrete. I was wandering is it possible to use an intumescent paint here, would it be helpful? Is it possible to include it somehow in calculations? Do you have any other idea how to handle such a case?
Best regards,
Maciej Ziemba
Thanks for your enquiry. Looking at your pdf file the connection is failing under the steel condition due to your grouted stand-off. Please Page 4 Section 4 Shear Load steel failure (with lever arm) utilization 340% I would suggest removing the grout thereby eliminating the stand-off . As an extra note intumescent paint being applied to the connection would be untested and therefore outside of any compliance documents.