Hanger Nails Above The Neutral Axis
Question:
I recall seeing a design recommendation several years ago regarding installation of hanger nails above the neutral axis of the bottom chord of a plated girder truss. The intent was to avoid dumping large loads into the bottom chord, below the neutral axis. Can you tell me where I can find this information?
Answer:
The recommendation is actually a design provision (section 7.5.3.2) in the Truss Plate Institute's ANSI/TPI 1. This provision provides guidance on design for tension perpendicular-to-grain forces and includes formulas to calculate the minimum distance the connection must extend past the centerline of the carrying member. Note that this provision only applies to girder trusses with a maximum of two plies.