We’ve covered some of this in the past on occasion, but I thought it might be worth a discussion of it’s own.
Got a plan today (For a commercial structure) with a note I haven’t seen yet. It said: “Truss manufacturer to provide erection bracing plan.” That’s the first time I’ve seen that on a plan.
So I called the company that provides our engineering, and talked it over with them. They consider erection bracing to be outside of the responsibilities of the truss supplier/engineer, and so don’t provide that service. They are considering doing it, though – For an added fee.
I’ve seen some other unusual notes too –
“Truss manufacturer to confirm that all walls are capable of supporting roof structure” That seems totally ridiculous to me.
“I-joist size and spacing per truss manufacturer” Not all truss manufacturers SELL I-joists. So why should they specify something they don’t sell?
Truss manufacturers also seem to be thrust into roles as architects/engineers frequently. We have to solve problems related to elevations that don’t work, and provide revised elevations/3D views. Most plans we get don’t have any engineering done on them, and simply have a dotted line labeled “BEAM” in the basement. We often have to specify all sorts of beams, from basement beams to beams that hold up the 2nd floor to garage door headers. Does that make us the “building designer” or “engineer of record”?
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So what am I getting at? Well, I’m wondering exactly what role truss manufacturers SHOULD play in overall structural design.
In many areas of the country, we’re being called on to specify erection bracing. That’s a relatively new development – Unheard of 5 years ago.
If we specify the truss erection bracing, should we also specify the PERMENANT bracing?
If we specify bracing for the truss system, how about the overall structure? Like the wall bracing?
How about wind design? If we’re required to design the trusses for wind, should we specify how the trusses are tied down to the walls? IF we are, should we design the full load path down to the foundation?
If we’re drawing and/or revising floor plans and elevations, should we just draw the whole dang thing to begin with? What’s the point in having an architect and engineer if were’re doing/revising all their work?
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I realize I’m covering a heck of a lot of ground here. I’m not trying to say things should be one way or the other – I already know what I think and am curious what you think.
Where should the truss manufacturers draw the line on engineering and/or design responsibilities?
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Replies
boss.. here in RI .. the truss mfr. does exactly that ..if they want to sell trusses in RI , they have to comply
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If we specify the truss erection bracing, should we also specify the PERMENANT bracing?
If we specify bracing for the truss system, how about the overall structure? Like the wall bracing?
How about wind design? If we're required to design the trusses for wind, should we specify how the trusses are tied down to the walls? IF we are, should we design the full load path down to the foundation? >>>>>
I tell my salesman we're building in a coastal zone and they design the truss for 90 mile /hr uplift.... they also specify PERMANENT bracing and note it on the plan.. and they specify and sell the correct tie downs for the truss and the wind conditions..and they include a 6 page "HIB-91 Summary Sheet ", printed on pink heavy stock paper with orange highlighted blocks describing how to handle, install and brace the trusses...
if you want I can mail you a full kit that they deliver with each truss order.... I have to give my building inspector a copy of the engineered drawings so he can check the tie-downs and bracing.. it's been that way for at least 5 years that i can think of...
Mike Smith Rhode Island : Design / Build / Repair / Restore
Thanks for the reply, Mike. I was beginning to wonder if anyone was going to reply. Never know what threads will stir up a firestorm, and which ones will just fizzle.
I've seen the kits that are sent out by many truss companies. Again, that isn't really the issue I was trying to raise. (But I appreciate the offer)
Basically, I wasn't talking about how it's done in any particular area, but rather what SHOULD realistically be done in general. ie:should the truss manufacturer specify hold-downs, and why? etc.
If electricity comes from electrons... does that mean that morality comes from morons?
I think it's a customer service issue. It's a competetive world out there and any edge over the competition keeps them coming back.
It's easy to be the cheapest guy in town, just reduce prices, but it's a tough making a profit. If you can save the customer headaches and a whole lot of phone calls and running around, they will pay.
There are many small truss shops in this area that only make trusses. If I buy from them I do all the leg work. Hell I ain't got that kind of time my buisness is growing and they are the same size as 10 years ago, and I fear if they don't change, will be gone in another 10 years.
It's the oldest sales technique in the book.... Solve a customers problems and get the order.
yeah.. i agree... if the truss mfr. didn't sub out the engineering , i'd have to hire a civil engineer to prove the wind uplift calcs and also spec the tie-downs... my Bldg. Inspecotr isn not going to stick his neck out.. so, the engineering could easily cost more than the small truss order ( my last one was [9] 25' scissor trusses ).. this way. the truss company has an engineer on retainer .. everyone gets the calcs and the printouts.. something for everyone... it would certainly mean a buy /no buy decision for meMike Smith Rhode Island : Design / Build / Repair / Restore