Nulukkizdin
Structural
All,
I'm putting together a spreadsheet right now to analyze a multi-story wood building that takes advantage of the "open front structure" provisions of the 2015 SDPWS. We meet all requirements to allow us to idealize our diaphragm as rigid, so we're headed that direction. Basically I'm inputting my diaphragm geometry and wall geometry, and using the spreadsheet to distribute my applied load to the various walls based on stiffness. As of now, I'm treating my stiffness term as 4(h/L)^3+3(h/L) and getting results that match up almost exactly with outputs from RAM SS and RAM Elements. At some point I'll update to include more accurate SW deflection components based on NDS, but that will be for later.
My question at the moment is how best to deal with the rigidity effects that come as a result of multiple stories of shear walls. Idealizing the walls as continuous along their height (the way they'd be treated in an FEM layout) gives them continuity of deflection along their height that changes their rigidity in the rigid diaphragm example. As such, whereas Wall #1 sees 5k in a single story rigid diaphragm analysis (both in spreadsheet and FEM), it will not attract 10k in a two-story FEM model with the same load applied at both stories. The spreadsheet approach treats these as discreet floors and thus simply will double the load.
I assume there to be some sort of modifier of rigidity as multiple levels are encountered in your building. Does anyone have any insight into the best way to quantify these multi-story effects of shearwalls as they pertain to rigid diaphragm force distribution?
Thanks!
I'm putting together a spreadsheet right now to analyze a multi-story wood building that takes advantage of the "open front structure" provisions of the 2015 SDPWS. We meet all requirements to allow us to idealize our diaphragm as rigid, so we're headed that direction. Basically I'm inputting my diaphragm geometry and wall geometry, and using the spreadsheet to distribute my applied load to the various walls based on stiffness. As of now, I'm treating my stiffness term as 4(h/L)^3+3(h/L) and getting results that match up almost exactly with outputs from RAM SS and RAM Elements. At some point I'll update to include more accurate SW deflection components based on NDS, but that will be for later.
My question at the moment is how best to deal with the rigidity effects that come as a result of multiple stories of shear walls. Idealizing the walls as continuous along their height (the way they'd be treated in an FEM layout) gives them continuity of deflection along their height that changes their rigidity in the rigid diaphragm example. As such, whereas Wall #1 sees 5k in a single story rigid diaphragm analysis (both in spreadsheet and FEM), it will not attract 10k in a two-story FEM model with the same load applied at both stories. The spreadsheet approach treats these as discreet floors and thus simply will double the load.
I assume there to be some sort of modifier of rigidity as multiple levels are encountered in your building. Does anyone have any insight into the best way to quantify these multi-story effects of shearwalls as they pertain to rigid diaphragm force distribution?
Thanks!