RE: RAM Frame Story Shear with Multiple Diaphragms

Jeffrey Champlin — Fri, 04 Dec 2015 17:18:09 GMT

Thank you Seth!

RE: RAM Frame Story Shear with Multiple Diaphragms

Seth Guthrie — Fri, 04 Dec 2015 16:44:06 GMT

When the diaphragm is pseudo-flexible, the location of the graphic for the diaphragm shear is largely irrelevant. This wiki indicates that it's somewhere near the geometric center. communities.bentley.com/.../8430.ram-frame-building-and-frame-story-shear

If you look at the building story shear report, you'll see 4 lines in the table for diaphragms 1,2,3 and "None". There is a "None" diaphragm because some of the chevron braces are not connected to any diaphragm, so the force in those braces shows up in the None row (and also on the graphic, near the very center). That's explained on the same wiki. You can change the criteria - diaphragm - disconnect option to prevent that. Since you don't have a rigid diaphragm it make no difference in other results.

I think the beam axial forces are OK. Keep in mind, you have nodal loads applied at all three joints of the chevron frames typically.

Finally, it's worth noting that the program generated wind loads on this structure won't be correct. We will apply a full amount of windward and leeward pressure to each diaphragm like we would to three towers. I would recommend using defined loads. More on wind loads here: communities.bentley.com/.../ramss-wind-loads-faq

RE: RAM Frame Story Shear with Multiple Diaphragms

Jeffrey Champlin — Thu, 03 Dec 2015 21:29:37 GMT

The name of the uploaded file is "2015-12-03 Champlin Exp Jnt Building". Thank you for your help.