Why can't NDS Table 4.2B for High Load Diaphragms be used for shear walls?
Why can't NDS Table 4.2B for High Load Diaphragms be used for shear walls?
(OP)
I can't find any information as to why the shear values for diaphragms in the NDS SDPWS Ch 4.2 for High Load Diaphragms can't be used for shear walls. As long as the underlying framing and nailing patterns are what is required for use of the values in that table, what is the difference whether the sheathing is applied horizontally or vertically? Isn't shear just shear? Is it because horizontal diaphragms typically have all four sides attached to boundary elements and shear walls typically only have two? I was trying to rationalize why that might make a difference but really, the way shear works that shouldn't matter.
I contacted AWS technical support to ask and the response I got was:
" The diaphragm tests are not subject to the same gravity load as the shear wall tests, so it’s not an apples to apples comparison."
Any idea what gravity load shear walls might be subjected to that horizontal diaphragms would not? How much difference could the gravity weight of a vertical shear wall make to it's shear strength?
Can anyone help with understanding this question about using horizontal diaphragms values for shear walls?
I contacted AWS technical support to ask and the response I got was:
" The diaphragm tests are not subject to the same gravity load as the shear wall tests, so it’s not an apples to apples comparison."
Any idea what gravity load shear walls might be subjected to that horizontal diaphragms would not? How much difference could the gravity weight of a vertical shear wall make to it's shear strength?
Can anyone help with understanding this question about using horizontal diaphragms values for shear walls?






RE: Why can't NDS Table 4.2B for High Load Diaphragms be used for shear walls?
RE: Why can't NDS Table 4.2B for High Load Diaphragms be used for shear walls?
I can see the gravity of the system effecting your boundary elements, load sharing of studs/sheathing/nails, stability of the members within the wall including the field, and maybe some second orders i cannot even fully understand at this hour today.
RE: Why can't NDS Table 4.2B for High Load Diaphragms be used for shear walls?
I have a retrofit application for which sheathing on both sides of the wall would be primitively expensive, (cabinetry, plumbing, etc. on opposite wall). Need a 6 ft long, 8 ft tall segment of wood framed wall to deliver 1118 lb/ft of shear strength (ASD, seismic). NDS Table 4.3A for shear walls gives up single sided ply sheathing at 870 lb.ft (ASD, seismic)
RE: Why can't NDS Table 4.2B for High Load Diaphragms be used for shear walls?
RE: Why can't NDS Table 4.2B for High Load Diaphragms be used for shear walls?
I think I'm just going to with single sided 5/8" Struct 1 sheathing with high load diaphragm 10d 2 row nailing (they only need 1 1/2" min embedment in framing to be effective) with retrofit wall studs, bottom plates and collectors. I think that will fly. With modification factors that wall should have a shear value of v = 1180 lb/ft (ASD). Just what I need.