Open-Web Steel Joist under Blast Loading

[mlevario99]

I am designing an elementary school inside a military base, this is actually a site adapt, but now I need to check the structure for blast design. The roof joists span more than the 30' specified under the UFC 4-010-01, so I need to check them for blast loading. I have access to the SBEDS program. I was doing some hand calculations based on the Handbook for Blast Resistant Design of Buildings, I am also following UFC 3-340-02. But I am getting different pressures with SBEDS and UFC 3-340-02, has anyone done calculations for blast design on steel joists, something that I can reference too.
Thank you for your help.

 

[JLNJ]

The blast guys I work with don't like joists at all. Too little ductility and too much catastrophic failure.