Design

I am doing research for clients who have flat roof trusses to which they are adding a second story. We are now looking for information on the trusses to determine what their load capability is. What do you need to know to help us determine this?

IBC 2012/2015 2303.4.6 and IBC 2012/2015 2303.4.7 state: 
2303.4.6 TPI 1 specifications. In addition to Sections 2303.4.1 through 2303.4.5, the design, manufacture and quality assurance of metal-plate-connected wood trusses shall be in accordance with TPI 1. Job-site inspections shall be in compliance with Section 110.4, as applicable.

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 I, as a truss manufacturer, adequately advise my customer against the dangers of 60 ft. and over truss span installations?

I have just moved into a new home and during the construction I noticed that one of the trusses in the garage was damaged. The web plate had come off in two different locations. I notified the builder and they said they would take care of it. Approximately two weeks after I moved in, I noticed the ceiling in the garage started to sag, so I went into the space above the garage and found the truss was never repaired. I again notified the builder and they sent someone to fix it. I went and looked at the fix and this is where my question comes in.

We have been specifying laminated veneer lumber (LVL) beams for some time now. The plans usually state, “Beam to be engineered and supplied by truss manufacturer.” What kind of liability issues do I need to watch out for?

I have mono trusses on either side of a firewall. I have the fire rating/wall material between them. Can I place a ridge vent above these two? Or should I use vents? How do I calculate the appropriate vent sizes and styles?

I have built a 30 ft. x 40 ft. pole barn with nine 30 ft. 2x4 7/12 pitch trusses that are 5 ft. O.C. I am planning to finish out the interior and will attach 7/16 x 4 x 8 OSB sheets to the trusses for my ceiling. Along with this, I will have to add several 2x4 nailers across the 30 ft. span between the trusses to attach the sheeting to. My question is: will these trusses have any problem supporting this ceiling? I am not planning on anything being placed in the section above the ceiling and there will be no walls or supports erected between the ceiling and the floor.

A question has come up concerning sloped roof trusses and fire assembly ratings. Some are reluctant to rely on test results from flat (parallel chord) trusses applied to sloped roof trusses. Do you have any information regarding the suitability of the fire rated ceiling assemblies for sloped roof trusses? Does the “minimum depth” requirement of the parallel chord assembly apply to the minimum depth of a sloped roof truss (i.e., heel height?)

I am reviewing a truss package that includes multi-ply trusses. Where do I find the requirements for the attachment of the individual trusses to each other (nails and/or bolts)? Is this a requirement that the structural engineer of record needs to supply or is it the responsibility of the truss manufacturer to design?