Mr. Kapustka,
Diaphragm stress concentrations aren't included in FEMA P-1051 example pages 6-10 through 6-40 because they aren't pertinent to the examples being presented. The examples are intended to demonstrate the distribution of forces vertically through the structural system. They don't demonstrate how to design the diaphragm which would be another complete example in itself for any one floor level.
The CE discipline is completely aware of engineering mechanics issues of stress concentrations in structural materials including how and when they must be considered and when they are irrelevant. For example, stress concentrations are included with considerable attention to detail in bridge connections between structural members especially where cyclic loading causes fatigue.
Stress concentrations are included in the design of seismic detailing and connections between framing members.
Civil Engineers expressly consider force concentrations in diaphragms when they are relevant, such as diaphragms with openings or reentrant corners. They are not considered and are irrelevant to the design of many rectangular diaphragms without openings as may be the case for many building diaphragms.
Your assertion that fixed beams and columns in buildings must have rounds or bevels indicates a lack of understanding about how buildings are built (and have been for a very long time). Bridges are in fact designed with these features when necessary.
I hope I've been able to provide some enlightenment on the topic for you.
Sincerely,
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Brett King P.E., M.ASCE
Senior Structural Engineer
GHD Inc.
Lake Oswego OR
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Original Message:
Sent: 04-23-2018 02:38
From: Franklin Kapustka
Subject: How to calculate total diaphragm forces
With regard to that document, on page 10-40, I do not see stress concentrations applied.
Is the civil engineering community waiting for an invitation from the engineering mechanics community on the application of stress concentrations to standard calculations? Any fixed frame should have rounds or bevels when transitioning from beams to columns.
I had the calculations in a 400 engineering mechanics course taught by Dr. Loren Zachary (the department chair and author of engineering mechanics books). Quite honestly, the fact that I seem to be on a bit of an education island on such an important topic for a quarter of a century is just scary.
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Franklin Kapustka P.E., S.M.ASCE
Student
N/A
Aloha OR
Original Message:
Sent: 04-21-2018 12:34
From: Marcelo Dasilva
Subject: How to calculate total diaphragm forces
FEMA's wepage has the answer you are looking for...
https://www.fema.gov/media-library/assets/documents/107646
take a look at chapter 6 of 2015 NEHRP Provisions: Design Examples (FEMA P-1051)
Cheers,
Marcelo
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Marcelo Dasilva, Ph.D., P.E.
Austin, TX
Original Message:
Sent: 04-03-2018 02:59
From: Md Mahmud
Subject: How to calculate total diaphragm forces
Does anyone have an example solution of how to calculate total diaphragm forces using the equation from FEMA 310?