Large wood truss spans

[JStructsteel]

Have a 70' wood roof truss span, on 2x6 walls. Anyone got any details of the bearing/diaphram details? 2x10 bottom chords/2x8 top chords. my first thought is to have blocking in between each truss. The architect I am working with wants minimal detail/involvement from me. Im worried he wont get it right.

let me know what you think

Jim

 

[msquared48]

The Architect needs to be set straight here. You need to inform him that you will need to be involved in the calculations and details, to include any extra lateral bracing of the truss members. He is not the structural engineer and he came to you. If he balks, turn your back and walk away. It's not worth the fight, or litigation.

Mike McCann, PE, SE (WA)

 

[Triangled]

way agreed, and wood trusses accumulate challenges with length, and 70 footers need careful knowledgeable attention

 

[JStructsteel]

Thanks
As usual this started out with him wanting a couple of headers designed, and has snowballed into this.

 

[KootK]

I think that WTCA gives you a pass on blocking for heel heights less than 6". For everything taller, you need blocking. This issue isn't generally related to span, however, as unit shear stresses remain aren't necessarily greater with increasing span.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[dcarr82775]

For trusses over 60-ft I believe special inspection is required on erection.

 

[Archie264]

Consider firing this client. He wants something for nothing so from a business point of view there's no point wasting your time with him, unless there's some intangible* involved. (*I.e. networking opportunities, he's your father-in-law, etc.) From an engineering point of view he might get people killed and you'll be on the hook for the liability. There should be other work out there, maybe consider letting this guy walk.

PS: I've dealt with this type, they don't always pay their bills so keep that in mind as you're weighing just how far out to extend your neck. Good luck.