![]() ![]() Note that even though there are industry "norms", most manufacturers will get even more refined by adjusting the load capacity of their tooth-plate connectors through testing. You cannot just apply regular methods as listed above That is hopeless. They are normally built to a highly specialized design procedure out of an industry association. Timber trusses are notoriously difficult for the average Structural Engineer to design/check, regardless of software used. If you can explain to me how to attach my risa file to this message, I'd be happy to. What else am I forgetting? Are there any other "tricks" for using RISA3D for truss design? I have the ends pinned for the web members and fixed for the chords. I have the "Cr" box checked for all members because it's a repetitive truss every 2ft.ħ. For the unbraced length of the bottom chord I have Le2 = Le_bend_bot = 0 (continuously braced by sheathing/attic) and Le1 = Le_bend_top = segment. For the unbraced length of the top chord I have Le2 = Le_bend_top = 0 (continuously braced by sheathing/roofing) and Le1 = Le_bend_bot = segment. I have one support pinned and one with a roller, and I have the out of plane (Z) axis pinned at all nodes since it's a 2D model in RISA3D.ĥ. ![]() Is one way better than the other in RISA?Ĥ. I also tried using one continuous member for each half of the top chord and one for the bottom chord. In both cases, I kept the member end releases fixed for the chords so they acted continuously. I did the same thing with the bottom chord. I tried breaking the top chord apart so that it was a separate member between each pair of panel points. Since I already have factors in the load combinations, can I make the Cd factors = 1.0?ģ. The program automatically includes Cd factors for wood design. I'm using the standard IBC ASD load combinations. Is this correct, or do I need to translate them into joint loads?Ģ. I'm applying the loads as distributed loads (k/ft) along the length of the top chords. Here are some of the things that I'm wondering if I need to fix in the model in order to get accurate results:ġ. This doesn't make sense to me because it's an existing truss and I'm only using 10psf dead load and 20psf snow load. The results indicate the some of the members are highly overstressed for both bending and shear.
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