Engineering design of the lumber has been improved
The truss engineering software now takes into account the rigidity of the joint at pitch breaks. Compared to previous versions, this engineering change will have the general effect of reducing chord lumber grades and/or sizes. For some pitch break joints this will also have the impact of occasionally increasing plate sizes, compared with earlier version.
To see the benefits of the improved lumber design, you will need to run Matrix Analysis. In the Engineering/Design presets, on the Design tab, there is preset for “Requested Analysis Type”. Select the “Force Matrix” option, then press Save as Defaults. As you create new trusses these will be run using Matrix Analysis. Pre-existing trusses that were run under ‘Automatic’ will still be run under ‘Automatic’ unless you change this preset and then redesign. To obtain the most economical lumber design, Keymark recommends setting “Force Matrix” as your default on a going-forward basis.
A preset is available to designers that allows/disallows designing pitch break to carry moment. For existing trusses, this checkbox is off. This preserves the design of the older truss.
New Labor Factors
New labor factors based on number of pitch breaks. The sum of the following three is equal to the current labor factor - # of Pitch Break Joints, which was the total number of pitch breaks, including heel joints
# TC Pitch Breaks
# BC Pitch Breaks
# Heel Joints
New labor factors based on number of plies:
Total Length of Pieces per x Plies
Length of Span per x Plies
Total Board Footage per x Plies
Support Additional Gable Data in the ITR/ITF Import
Improvements have been made in Keybuild that allow users to define more gable properties. This data is then available in the ITR/ITF files for importing into KeyTruss. The key data that is being passed is:
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Structural vs Non-structural gable
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Vent height for rectangular gables
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Drop dimension for dropped top gables
This data then pre-populates the corresponding data in the Gable Design macro. When the truss is open, go to menu --> Geometry --> Gable.
The checkbox for Gable will be checked and either Non-Structural or Structural will be checked and Spacing will be pre-populated:
If the gable is a dropped top gable, the Drop Top checkbox will be checked and Drop Dimension will be pre-populated:
If the gable has a vent type of triangular or rectangular, the selection will be made on the Vents tab and the Opening Width and Opening Height will be prepopulated:
There will be additional data passed in future releases.
Agricultural Trusses
There are now separate presets for agricultural trusses. These can be accessed from Preset --> Ag Truss Eng.\ Design.
When first creating an Ag Truss, it is important to check the Ag indicator before changing your presets. The program using this indicator to determine which set of presets to use.
You can also turn on a system presets that will flag all new trusses as agricultural trusses.
Support of Michigan Building Code
Michigan building code is now supported.
