Sloped Truss w/Flush Purlins

[BadgerPE]

I have an owner that is pretty set on having a roof framing system like the one in the attached picture. We are in very preliminary stages now and are just in the process of researching this and other options. The attached framing system is from the UK and we are in the US so I doubt that the owner will want to ship them from overseas for his project. I am just curious if anyone here knows of a manufacturer of similar trusses in the US?

I am thinking at this point that we may be able to convince the owner that some other option may work better/cost less.

 

[EngineeringEric]

Why is this used anywhere? I am actually curious if the only reason is to support thin decking over tightly spaced purlins with wider spaced bar joists on even wider spaced steel beams.

I would think it would be easier to use a more conventional configuration from SJI. Place the decking spanning joists, or if purlins are used to place the purlins directly on top of the joists and detail out some nice diaphragm connections. (??)

Worse comes to worse, explain to the owner that there is a reason we as design professional are all required. We know what is best in multiple applications and our markets. The owner is not a designer even if they fancy themselves that way.

 

[dhengr]

Crackerjack47:
Why not have the owner/client go to his favorite supplier in the UK, and get a price for a complete, installed, and guaranteed roof structure system, to your loads and specs., so you can compare it to what we would normally do here? Make sure to include the cost of the pink and silver paint, if that’s what he wants. We really have to be quicker on our feet, to stop some of this tilting at wind mills which some clients think we should pursue. Almost anything is possible, but they do have to be willing to pay us to pursue some of this silliness. I would assume that what he really wants is a roof system which supports the imposed loads and keeps the wind, snow and rail out. After you’re done with that, he can hire someone to paint a fresco up there if he wishes.

 

[BadgerPE]

Thanks for the feedback! We are in the process of discussing other options with the owner. A few things have changed already on the project that make parallel chord trusses a more viable option. As a side note, this particular client brings a lot of business our way so I was trying to do my due diligence before explicitly stating that the option was a bad one, even though I thought it up front.

 

[rowingengineer]

I don't see this system being all that bad. The main reason I can see someone using it is to get minimum depth of roof. I'm not in the US but I can't see why you couldn't get a similar system happening through the use of an RHS truss.

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."