Concentrated Loads On LH Joists

[StructuralEd]

Looking at a vintage Vulcraft joist catalog, they noted that concentrated loads are allowed on LH joists (without specifying special design) provided that the moment and reaction do not exceed 85% of the allowable values and that the concentrated load doesn't exceed 12% of the allowable reaction.

Are those unique to Vulcraft joists or were they standard practice, and perhaps an SJI spec guideline?

 

[JedClampett]

I'd be cautious about using this for any manufacturer, even Vulcraft, unless you get acceptance in writing. These guys design for the specified loads and not one ounce more.

 

[StructuralEd]

Jed, this is about a building built in the same general era as the Vulcraft catalog and the catalog specifically notes that it is an appropriate procedure.

The question is whether that was a general SJI design approach applicable to other manufacturers.