Because the SMACNA Duct Construction Standards allow certain panel widths to be unreinforced at certain gauges, it becomes necessary to be able to set different long side and short side Tie Rod quantities. For example; on a 56” long TDC/TDF duct at a 3” SP Classification, the 61”-84” long side panel widths require (2) Center Tie Rods and (1) End Tie Rod, and no Tie Rods on the short side up to a 36” panel width, at 20 gauge. This is possible within the parameters of the current program. A duct with the same long side, but with short sides 37”-60” requires (1) Center Tie Rod and (1) End Tie Rod on the short side. Currently there is no way in the program to change the Center or the End Tie Rod quantities based on the panel width. Once long side only is turned off or set to 0, the quantities are set by the duct length and must be the same for both long and short sides. This means the example duct will get (2) Center Tie Rods and (1) End Tie Rod, on the short side, when it requires only (1) Center Tie Rod and (1) End Tie Rod. There are other examples I could use where the short side requires only (1) End Tie Rod and no Center Tie Rods but would get (2) Center Tie Rods. I propose adding a column to the Stiffener Breakpoints dialog box that would allow us to set the Tie Rod quantities using both the duct length and the panel width, as shown below.
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