Metal shop truss ideas

[Mailbux]

Hi guys and gals,

I need some help with my build. I have just poured my concrete and set the poles for my future shop. The poles are galvanized 4x4 poles 12ft high every 10 feet apart. The shop is going to be 30feet wide by 75 feet. I have considered using 2x8 cee channel 18 gauge as the truss. I already have the cee chanels so hope I can get some advice on the if this will work? I'm in Houston so no snow load.

 

[Mailbux]

The pitch wil be a 3/12.

Thanks in advance

 

[Mailbux]

here is a sketch

 

[tjdux]

This sounds like a good question for city building code office and probably also an engineer...

I know for lumber there are calculators to determine lumber size but i dont know about steel.

18 awg seems pretty thin for the span you're traveling but at 8 inches wide you may be ok.

Also maybe im wrong here but we always just call it channel iron, I don't beleive you need the "cee".

Sent from my SM-G900V using Tapatalk

 

[readhead]

He is talking about metal building components. Instead of structural shapes they are rolled sheet metal and come as either "C's" or "Z's". It is possible but the design of the various cords would need to be designed by an engineer to avoid failure. You don't have a snow load but just like your house the roof has to safely support itself.

 

[Mailbux]

Thanks guys for the info

 

[kd3pc]

at a minimum, you will need a lot of stringers between those C channels to keep them from rolling as stresses change. Wind load will be your challenge.. Your desired lengths will likely rule their use out for this build. Then you will need nailers up the C's for metal roof or even more stringers on 4 ft centers for OSB/ply roofing.

Engineer...needed for this one. Especially if you want a conventional roof.

best of luck

 

[Mailbux]

I'm going with 26 gauge metal roof, but yes your right. I can probably use the c purlins them for something else

 

[Mailbux]

Any ideas what to use, the width should be 29feet 4 inches( minus the 2 4x4 posts)

 

[Radix2]

The least expensive, fastest and easiest thing is to get some wood trusses.

They will be already engineered and ready to go - with no guess work.

Or if you must have metal, source metal trusses or at least get a design to copy, know anyone with what you want. You need to be very careful how you load these types of metal channels, they are very strong in some directions and very weak in others.

 

[73RR]

You don't have any snow to speak of but you guys have some serious wind issues at times.
The poles are galvanized 4x4 poles 12ft high every 10 feet apart
Is this a tube section?
Wall thickness?
How is it connected to the slab, or are they set in concrete?
Who selected the 'post' size?
What design criteria was used?

Lots-o-questions that need to answered...you really need to find a local engineer.

 

[penright]

The guy who built my building, said "We buy the truss already made, there is just too much liability in them". I bet if you call around you can get some quotes. At least then you can see what they would use to make them. Here is a picture of mind being built, so you can kind of see what they used.

The truss spans are 24 feet.

 

[Mailbux]

Here are some pics of the build, hopefully this helps

 

[Mailbux]

Thanks guys, this is a real help. Penright great pics that's a nice building

 

[readhead]

Just curious. How did you get this far without any plans or design? What are the posts sitting on ?

 

[rburke65]

I know they are built like that everyday but here in Ohio, I not crazy about a build with trusses every 10'. Way too far apart for me. As always, just my opinion.

 

[Mailbux]

My plans where to go with wooden trusses , but now considering metal. I have 4x4 galvanized post buried every 10feet

 

[readhead]

Is there a base plate on the post and how deep is it buried? How much concrete is under the posts?

 

[Mailbux]

Think I found some, these look like they might work. Perfect size too

 

[Mailbux]

@readhead the post are buried over 4ft deep

 

[GMCGarage]

Unless you have a flat bottomed truss, you will have some horizontal thrust you need to consider at the poles. Might not be much, but should consider it.

 

[plow]

Maybe this will help. It wasn't designed by an engineer though. I bought the steel pictured below and sketched it out on the floor with soap stone.




The tubing is 4" x 4" x 3/16". Base plates are 8"x 8" with 3/4" holes drilled at the corners. Again no engineer was involved. I'm going it on my own with the knowledge I've accumulated over the years. I have no snow load, and the roof purlins will be 8" as I plan on spanning 20' between joists. Metal roof if it matters.......

 

[plow]

Actually, the top pic is an older version. I'll post up the newer if you're interested. I revised the cross brace as I cant cut the angle with my homemade dry saw and I added an eve. I have all the metal cut for 6 truss sections. I may add a seventh before it's all said and done.

 

[GMCGarage]

I think alot of good advice has been offered. Without snow load, only other load to really worry about is wind load. If you dont need engineer review or building dept approval, go with what you know and whats been said above.

When in doubt, make it stout.

 

[plow]

^^^^yep^^^^