[five.five-six]

I was asked to bid a small job for a local municipality. Lighting and receptacles in a new small steel structure. The head of building services wants me to just drill 1/4" holes into the 2-1/2 square steel structural members to attach unistrut lengthwise across the roof trusses with 1/4" bolts and attach 4' fixtures to the unistrut.

Sounds simple but I am afraid that will weaken the steel , I had called the manufacture earlier in the week but here it is Saturday and I haven't had the call returned.


My thinking is beam clamps but I don't know, I have never worked on one of these structures and I have never seen beam clamps for 2-1/2 square tube.

 

[chewy]

I havent been allowed to drill steel since 2/22/2010 no engineer wants to sit infront of a panel of beaurecrats explaining why a catostrophic failure occured.

 

[socalelect]

Dude its just a carport , likely made by american steel , I have a couple of them , they are pretty cool anyways if I was you I would not drill the bottoms of the trusses , but I would drill the sides and use a l bracket to hang the strut on or just something to hang the lights from. Is it a 14 or 12 gauge tube ? What is the size of it and how many lights

 

[360max]

jackchain

 

[five.five-six]

Tubing is 12 gauge. the building is 45' by 20'. I have been advised that the area is subject to very high winds.

 

[socalelect]

Tubing is 12 gauge. the building is 45' by 20'. I have been advised that the area is subject to very high winds.

What part of the country ? Snow ? Need info

 

[johnnyontheside]

You could screw 3/4" minis to the steel and attach emt in place of the strut. Then attach mini to top of light and hang the light from emt.

 

[chicken steve]

We are not structural engineers 556.

Your 'head of buildings' municipal entity knows this, has a stamped architectural , and doesn't wish to budget any engineering into what most likely he forgot.

Do yourself a favor, bid to his wishes, then include a caveat dependent on some 3rd entity's decision, essentially landing liability on Mr H-O-B's lap

~CS~

 

[five.five-six]

What part of the country ? Snow ? Need info

I live in California, this "snow" you are asking about, is it the white stuff that I see on the TV news?



This facility is high enough that it may get a few inches every few years.

We are not structural engineers 556.

Your 'head of buildings' municipal entity knows this, has a stamped architectural , and doesn't wish to budget any engineering into what most likely he forgot.

Do yourself a favor, bid to his wishes, then include a caveat dependent on some 3rd entity's decision, essentially landing liability on Mr H-O-B's lap

~CS~

Yea, and here's the thing. Mr H-O-B has had several other similar structures, smaller and without sides lighted the way he prescribed. I didn't realize at the time but he was having a little uh-oh moment when I was questioning how to attach the unistrut.

 

[That_Dude]

I'd go with what the head of building service says. Drilling 1/4" hole should not be much of a problem in a 2 1/2" tube.

 

[socalelect]

Like I said just drill the holes on the sides and not bottoms of the trusses , think of the tube like a I beam you sure as hell wouldn't drill the flanges of that

 

[Cow]

I would drill the 1/4" holes and not think twice about it. How many screws do you think go through the roof sheeting? And you're worried about a few 1/4" holes....?

 

[jza]

Why don't you sell the "head of the building" on some beam clamps if that's what you want to use? After explaining to him the added benefits and labour savings, they should sell themselves.

 

[socalelect]

I would drill the 1/4" holes and not think twice about it. How many screws do you think go through the roof sheeting? And you're worried about a few 1/4" holes....?

How is he going to thread the holes ? 12 gauge tube won't make many threads with a course threaded fastner

 

[five.five-six]

I don't know of any clamps that fit that tube. Perhaps square u bolts.

 

[socalelect]

Why don't you sell the "head of the building" on some beam clamps if that's what you want to use? After explaining to him the added benefits and labour savings, they should sell themselves.

Beam clamps for sq tube I never seen em

 

[socalelect]

I don't know of any clamps that fit that tube. Perhaps square u bolts.

Ya beat me to it

 

[chicken steve]

Yea, and here's the thing. Mr H-O-B has had several other similar structures, smaller and without sides lighted the way he prescribed. I didn't realize at the time but he was having a little uh-oh moment when I was questioning how to attach the unistrut.

I'd just carefully word any written exchange so that it remains his uh-oh in any event 556

~CS~

 

[five.five-six]

I'd just carefully word any written exchange so that it remains his uh-oh in any event 556

~CS~

At the time I was discussing the connection system, I hadn't seen the other structures yet...


I think square U-Bolts will be fine and I won't need any written disclaimers. I am going to play with my kids and then have the quote out by Monday morning.

 

[Cow]

How is he going to thread the holes ? 12 gauge tube won't make many threads with a course threaded fastner

Honestly, I hadn't even thought about it, I figured he knew how he was doing it. I would rather use some #14 x 1" self drilling sheetmetal screws with a 3/8" hex head that Fastenal sells, I keep them on the truck in a few different sizes.

http://www.fastenal.com/web/product...Mv84VlxfdkJRDlJLMt071yB!-628775415!-888801569