I have an opening that's about 11' wide, framed on the sides with LVL and a steel beam spanning the opening, which is in a load bearing wall. We want to install a french door assembly that's roughly 10' wide in this opening. When the engineer spec'd the beam for this opening, he mentioned that a door should never be secured to the beam it self or anything attached to the beam, because if the beam deflects it will wedge the door shut (or break the glass, etc).
My question is, how to we secure a door in this opening then? It seems like only securing it to the floor and the two sides will not be enough. Do I have to build some sort of mini-header that rests on top of some 4x4s or something? Or can I in fact secure the door to the wood that's attached to the beam?
One other question, should the door be installed resting on the subfloor or on the finished floor (hardwood in this case).