roof diaphram questions

[wds1]

Questions on roof diaphrams. Text books and field observations appear to differ. Assume a typ. building with parapet masonry walls, metal decking, and bar joist.
1. Walls with Bar joist perpend. to wall:
a. Chords: consist of bond beams, contin. angles, or portions of metal deck. I never see contin. angles and I suspect that bond beams are only there some of the time.
b. Shear transfer bet. metal deck and wall: bar joist seats can provide transfer. If metal deck requires intermediate side lap connections near wall, then contin. angles must be provided for shear transfer. I have Not seen any.
2. Walls // to bar joist.
a. bar joist adjacent to wall: bar joist or bond beam can act as chord. Shear transfer is required bet. the web and chord. A positive tension/compression connection must be provided between the wall and the bar joist to support the wall. The only thing I see is the bridging, which appears inadequate.
b. A ledger angle on the wall. Provides the chord, the shear transfer, and the tens./compress. connection. The ledger angle would seem to be the prefered method, but it is the least observed.
3. metal deck fasteners and spacing can vary with the amount of required shear.
Please respond and let me know if I am misinterpreting something. Thank you for your comments.

 

[UcfSE]

Is there a question here or did I missed it?

With what you say you don't see the building(s) doesn't sound complete enough to have been observed, as in you saw it before these things were installed. Keep in mind there are many ways to detail a building and its connections, and all can be right if done correctly. I would think it very unusual to leave out these major and pretty common components. If they are leaving out components and the inspector isn't catching them that isn't your fault as long as you have your stuff together on the drawings.

Bond beams can act as the chord for the diaphragm. So can the continuous deck angle. If properly designed and detailed a joist can also though that would be unusual. Ledger angles are not necessarily preferred - they cause unnecessary eccentricity on the wall. That makes the wall more expensive. Metal deck in itself is generally not used for chord forces. Personally I would use a deck angle all around and provide expansion bolts or epoxy bolts to handle the tension and shear.