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LGSS - Light Gauge Steel Stud question

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I have been designing a clients steel stud homes when I discovered a problem
related to their past developments.
An engineer that they hired (and recenly completed a book on metal stud
construction)designed their headers using 20 Gauge 8 and 12" sections. These
were WCJ sections where the J represents no cutouts.

The manufactures catalog (Steeler in Washington) clearly shows that the H/t
ratio for web crippling is exceeded in a 20 gauge 8 and 12" section.

The headers (assuming a maximum loading of 420 plf Roof Dead Load and 336
PLF Roof Live Load) are constructed as a box beam set flang to flange rather
than web to web. The beam is capped with a 20 gauge track top and bottom.

I need to suggest a retrofit for the homes under construction. In these
cases, only the inside face of header is available since the exterior is
already covered with either sheathing or foam board insulation.

I had thought of using an expansion wing nut (like the kind used to hang
something from drywall which fits through the whole and spreads out when
through.
Combined with a long threaded rod which would place pressure against the web
on the outside face of wall.

The reasoning is as follows:
I would think that the webs would buckel inward since they are braced by the
exterior finish and interior gypsum wallboard.
The bolts would brace the web from buckeling inword (or at least minimize
the potential for hazzard and be easy to install.
Finally, the bolts can be placed in the along the centerline of the flange
to provide lateral support at mid height and where it will have little
effect on bending.

The contractor suggested screwing in place an additional layer of thickness
to the web on the available side - I'm not comfortable here, but have a
feeling for how my bolted idea might be effective.

Any other suggestions?


Dennis Wish PE