Design Documents

I am a truss manufacturer in an area of the country that often has some pretty severe winters. It concerns me how little some of the local builders seem to know about snow load design. What are some of the things that need to be considered?

If trusses blew down from insufficient temporary bracing and the contractor put them back up without the knowledge of the truss manufacturer and gave the truss manufacturer a letter stating that the trusses were okay, is that sufficient? Do you know of any truss manufacturer who would accept this?

Can I put a wood deck (1/2 in. plywood) on top of the bottom chord of a 26 foot span truss 24 inches on center?

The Gypsum Association “Fire Resistance Design Manual” (GA-600-12) lists file RC2601 with two layers of 5/8 in. gypsum wallboard (GWB) on wood joists.

Are there any published studies or guidelines on the fire rating of floor trusses built with 2x3 lumber?

Can you explain drag loads and how to calculate a drag load pertaining to roof trusses?

I am currently putting together a set of truss specifications for a set of structural plans. I am interested to know of the most current publication that may specify industry standards in truss components (i.e. metal connector plates, wood quality and connection quality). Do you have any suggestions?

The Corps' guide spec for wood construction requires the drawings to indicate the design forces on each truss member for the worst loading condition. Loading conditions, of course, can include wind, snow build up, and unbalanced loading, to name a few. Many A/E firms submit drawings lacking these member forces, but instead show typical loading conditions. What does the wood truss fabricator want to see – truss diagrams with maximum loads on each member? Or would he prefer to design the truss from many required loading diagrams?

I was wondering if you have any information or anecdotes relating to the deflection performance of long span scissors trusses? We recently sold a job with 70 ft. long scissors trusses. The customer is in the process of installing the trusses and doesn't like the deflections he is seeing. To make matters worse, the scissors trusses are framing into a valley set (which we provided) that is erected on 35 ft. Howe trusses. The Howe trusses are exhibiting very little deflection. Any ideas?

How do you evaluate whether a metal plate connected truss is still usable after exposure to fire? Are there any recommended tests?