Diaphragms Spreadsheet - General Tab

The Diaphragms spreadsheet contains diaphragm information. For RISA-3D models there are two different versions of the Diaphragms spreadsheet; one for models which have been created in RISA-3D and another for models which are linked to RISAFloor.

To open the Diaphragms spreadsheet:

Open the Spreadsheets ribbon, as shown in the following image.

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Click on Data Entry.
Click on the Diaphragms checkbox, to open the Diaphragms spreadsheet.

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Alternatively, you can access the spreadsheet by clicking on Diaphragms in the Explorer panel, as shown in the following image.

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RISA-3D Only

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Rigid Diaphragms Spreadsheet

Column	Description
Node Label	The ‘Node Label’ column defines the primarynode for the diaphragm. For diaphragms in the ZX plane, the diaphragm will be created at the Y-coordinate of the specified node. Similarly, XY diaphragms will use the node's Z coordinate, and YZ diaphragms will use the node's X coordinate.
Plane	The ‘Plane’ column indicates which plane the diaphragm is in.
Inactive	When the ‘Inactive’ checkbox is checked, the diaphragm is ignored by the program. This is a convenient way to disable diaphragms without deleting them.
No Wind/Drift	You may designate any floor level as a No Wind / Drift (i.e. mezzanine) level in order to omit it from the generated wind load calculation and the drift calculations.

Note:

Only the in-plane rigidity is in play and not the out-of-plane rigidity.
There are not semi-rigid or flexible options for RISA-3D as a standalone program.

RISA-3D Linked With RISAFloor

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The following table lists the General tab settings and their descriptions.

General tab settings

Setting	Description
Elevation	Displays the elevation of the diaphragm. This is the same elevation as the floor which the diaphragm was created on.
Mass	Displays the dynamic mass tributary to the diaphragm. This mass is used to calculate seismic forces for both static and response spectra methods.
Mass MOI	Displays the dynamic mass moment of inertia of the diaphragm. This moment of inertia is used to calculate seismic forces for response spectra analysis.
Center of Mass	Displays the X and Z coordinates of the center of mass of each diaphragm. This is the location at which static (equivalent lateral force) seismic loads are applied for each diaphragm.
Eccentricities	Are the percent of length/width of the diaphragm which are used to place "accidental eccentric" seismic loads for each diaphragm. This only applies to the static (equivalent lateral force) procedure. See ASCE 7-16, Section 12.8.4.2 for more information.
Inactive (checkbox)	When the Inactive box is checked, the diaphragm will be ignored by the program. This is a convenient way to disable diaphragms without deleting them.
Diaphragm	Displays the diaphragm label. This label is used for the naming of Diaphragm Regions.
Type	Specifies whether the diaphragm is Rigid (Membrane) or Flexible for a Beam Supported Floor or Rigid (Membrane) or Semi-Rigid for Concrete Floor Slab. If a diaphragm has been defined as Flexible within RISAFloor it can be toggled between Rigid and Flexible in RISA-3D.
Region	Lists the diaphragm regions for each diaphragm. Diaphragm regions are used for the design of wood flexible diaphragms, and are also useful for explicitly defining how flexible load attribution is to be performed.
Design Rule	Specifies the Design Rule which is assigned to each region. Only the information on the Diaphragms tab of the Design Rules Spreadsheet is considered.
SGAF	The ‘Specific Gravity Adjustment Factor’ for the design of wood flexible diaphragms. For more information see AF&PA NDS SDPWS, Table A4.2, Note 2. This value defaults to 1. However, it should be manually changed if the framing supporting the wood flexible diaphragm is not Douglas Fir-Larch or Southern Pine.
Material	The ‘Material’ column specifies the material properties of the diaphragm (when a semi-rigid diaphragm is selected).
Thickness (in)	The ‘Thickness’ column indicates the thickness of the diaphragm (when a semi-rigid diaphragm is selected).
No Wind/Drift	You may designate any floor level as a No Wind/ Drift (i.e. mezzanine) level in order to omit it from the generated wind load calculation and the drift calculations.

Note: For information about the Wood Diaphragms tab see the Diaphragms - Analysis and Results topic