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The vibration design criterion for joists has been expanded to include all the bracing configurations in the NBC, and has been made more visible in the program input and output.
Input
Location of Vibration Input (v9 - Feature 199)
The input of the Floor sheathing, Lateral support, and Connection of floor sheathing fields for design of sawn lumber floor joists has been moved from a small dialog box invoked by a button in Beam View to Beam View itself, so that all data fields representing the member assembly are visible at the same time.
Lateral Support/Bracing Name Change (v9 - Feature 207)
The Lateral support input has been renamed Bracing to avoid confusion with the Lateral support input used for buckling design (KL factor). Note that these inputs remain independent because it is possible to support a member sufficiently for vibration but not for buckling design, for example when the strapping or other support is not tied into a fixed member in the structure.
Bracing Options (v9 - Feature 207)
The following options have been added to allow you to specify all the options listed in NBC A.9.23.4.2.(2)
Gypsum wall board
Ceiling w/furring
Ceiling w/furring & bridging
Concrete Topping
In addition, we have added a None (no design) option to allow you to opt out of vibration design. If this is selected, the other vibration inputs are disabled.
Sheathing Options (v9 - Feature 207)
½” sheathing has been removed, as it is no longer listed in the NBC. In its place, we have added
< 5/8” (no design) (Imperial)
< 15.5 mm (no design) (Metric)
If this is selected, all other vibration inputs are disabled and the program does not perform vibration design.
Change of Joist Spacing (v9 - Feature 207)
Since ½” (12.7 mm) is no longer an option, the program changes the sheathing thickness to 5/8” (15.5 mm) when 12” (300mm) is selected as the joist spacing. If < 5/8” (no design is currently selected, then the message box doesn’t appear and no change is made.
Design (v9 - Feature 207)
Furring and Concrete Topping
The constants A and B from Table A.9.23.4.2.(2)B for the vibration design equation have been added, allowing you to design for furring and concrete topping.
Gypsum Wall Board
When gypsum wall board is selected, the program uses the values for strapping, as per Note1 to Table A.9.23.4.2.(2)A .
No Design
If either None (no design) is selected for Bracing or < 5/8” (no design) is selected for sheathing, the program does not include vibration among the design criteria it checks. This allows you to opt out of vibration as a serviceability criterion as you can for deflection design by setting high deflection limits.
Output (v9 - Feature 69)
Input Echo (v9 - Feature 69)
The Floor sheathing, Bracing, and Connection of floor sheathing inputs for the design of sawn lumber floor joists are now echoed in the materials specification in the Design Check report.. These data previously were not output.
Furring and Concrete Topping (v9 - Feature 207)
The program outputs the minimum specifications given in NBC for furring and concrete topping, that is, 1x3@8” or 1x4@16” furring and 30-51 mm of 20 MPa concrete topping.
File I/O (v9 - Feature 207)
If a project file from a previous version that had ½” sheathing is opened, the program does not include vibration as a design criterion. You must select a thicker sheathing material to activate vibration design.
Vibration Message for I-Joists (v9 - Change 155)
The message that says the vibration details have changed when the joist spacing has changed has been removed for I-joist, for which it is not relevant.