lexpatrie
Structural
- Aug 20, 2009
- 1,060
Ok, so a bit of a resurrection.
First off, this seems to come up fairly often (I guess "often" is a relative term, as I know have my second one). On the first one, being it was a storm damage situation, I wasn't on the hook for actual calcs using generally accepted principles of mechanics and so forth, so I flagged the issue, noted the potential safety issue with stacking heavy materials on the deck, and said they'd need a structural engineer to review the lateral system, particularly the poured gypsum (with laid in gypsum boards and bulb tees), as it was wind-damaged, and released the report.
I'm expecting to have the same situation a second time, and again, am not explicitly on the hook for a sealed repair drawing, scope being more or less the same as the above project.
Here's the thing - I've never found diaphragm values (or maybe I did, and since I didn't need to design it, subsequently forgot, as I'll explain later, I have the ASTM in my e-horde).
So: Without further ado -
Diaphragm values are in ASTM C956. These are relatively high, not sure these are adjusted for "allowable" or an appropriate phi factor for ye California engineer types. (or at least they were in the 2004 I found, and the 2015 is a reaffirm of the 2004, so I don't expect any changes).
Articles of note: (I guess, I haven't read the J. Struct. Div. ones yet):
Your basic GA 300-73 which is available elsewhere (I'll add a link to an older thread later), that lacks diaphragm values, (and I have about forty copies of this on my local for some reason, which I've now tried to pare down), anyway, gravity loads oriented, fire resistant and so forth.
Regarding diaphragm values'
ASTM C956, (with a 2" minimum, is that the thickness of the poured gypsum or is that the whole thickness, including the gypsum form boards that I'm used to seeing from below?)
Articles:
Johnson, Lewis, Structural Behavior in a Gypsum Roof-Deck System, J. Struct. Div. (ASCE), 1966. (Note there are two replies to this article).
Both of those sound like lateral load oriented documents, I don't have them and don't know how useful they will be.
Where do folks think this belongs, as a FAQ? In the main forum? In the AISC forum as it's not (commonly) associated with concrete buildings?
First off, this seems to come up fairly often (I guess "often" is a relative term, as I know have my second one). On the first one, being it was a storm damage situation, I wasn't on the hook for actual calcs using generally accepted principles of mechanics and so forth, so I flagged the issue, noted the potential safety issue with stacking heavy materials on the deck, and said they'd need a structural engineer to review the lateral system, particularly the poured gypsum (with laid in gypsum boards and bulb tees), as it was wind-damaged, and released the report.
I'm expecting to have the same situation a second time, and again, am not explicitly on the hook for a sealed repair drawing, scope being more or less the same as the above project.
Here's the thing - I've never found diaphragm values (or maybe I did, and since I didn't need to design it, subsequently forgot, as I'll explain later, I have the ASTM in my e-horde).
So: Without further ado -
Diaphragm values are in ASTM C956. These are relatively high, not sure these are adjusted for "allowable" or an appropriate phi factor for ye California engineer types. (or at least they were in the 2004 I found, and the 2015 is a reaffirm of the 2004, so I don't expect any changes).
Articles of note: (I guess, I haven't read the J. Struct. Div. ones yet):
Your basic GA 300-73 which is available elsewhere (I'll add a link to an older thread later), that lacks diaphragm values, (and I have about forty copies of this on my local for some reason, which I've now tried to pare down), anyway, gravity loads oriented, fire resistant and so forth.
Regarding diaphragm values'
ASTM C956, (with a 2" minimum, is that the thickness of the poured gypsum or is that the whole thickness, including the gypsum form boards that I'm used to seeing from below?)
Articles:
Johnson, Lewis, Structural Behavior in a Gypsum Roof-Deck System, J. Struct. Div. (ASCE), 1966. (Note there are two replies to this article).
Google scholar: https://scholar.google.com/scholar?cites=17975173991489929685&as_sdt=5,24&sciodt=0,24&hl=en
Kunnath, Mehrain, Gates, Seismic Damage‐Control Design of Gypsum‐Roof Diaphragms, J. Struct. Div. (ASCE), 1994.
Citations (per Google Scholar) - https://scholar.google.com/scholar?cites=14732268673319789141&as_sdt=5,24&sciodt=0,24&hl=enBoth of those sound like lateral load oriented documents, I don't have them and don't know how useful they will be.
Where do folks think this belongs, as a FAQ? In the main forum? In the AISC forum as it's not (commonly) associated with concrete buildings?
