Issue link: http://alpine.uberflip.com/i/684939
Horizontal Deflection All trusses incur a certain amount of Horizontal Deflection. Certain truss shapes, such as the Scissor Truss above, are more prone to horizontal deflection than other trusses. There is a maximum allowable defection, and when exceeded, intelliVIEW displays a warning on the screen. Differential Deflection The two Hip Trusses above demonstrate Differential Deflection which can be explained as the difference in deflection of two adjacent trusses. The deflected distance between the #1 Hip and H9 is substantial. This is a condition that, although quite common, has the potential to cause problems in the field. The #1 Hip is multi-ply and some of the chords have been increased, resulting in a decrease in the deflection. H9 works without increasing the ply or lumber sizes; however, there is a higher degree of deflection. A similar condition is created when the adjacent truss (trusses in the same run) are different in shape i.e. Scissor Truss next to a Common Truss, or a full span truss next to a stubbed truss. Here are a few suggestions to reduce deflection: 1. Change web configuration 2. Increase chord sizes 3. Change truss profile (i.e. increase the depth of a flat truss or increase the difference between the top and bottom chord pitches of a scissors or vaulted type truss) 4. Decrease the on center spacing of the truss 5. A combination of the above.