Hanger

[Kurt.A]

It is awesome having some engineers on site with us to help us along.
Paul/Greg,
I have no idea what the design snow load is for our area. but at any one time during mid winter we will typically have 1-2 ft of snow on the ground. The weight of which really varies with moisture density more so than the visual amount of snow.
As far as the joints in the laminations all joints are spaced no less than 4 ft away from one another. The internal OSB laminations are also full depth of the beam less the top and bottom 2X6 plates.
I have considered putting in removable center posts and will be monitoring the beam flex as the snow load comes on. If the flex becomes more than an inch the posts will be going in along with screw jacks to level things back up.
The pitch is the same as our hay shed and snow slip occurs all winter long on it. Ambient temperature is the deciding factor here. -20 C snow never slips, -2 C snow never stops sliping.
All excellent points to be brought up for clarification!

[beeryboats]

Let me toss this out there. Are the pre made trusses, sold by Menards, Lowes, etc, made to be used for an open full span roof? In other words, would a series of 40' trusses spaced 24" on center work if supported by some well built walls on three sides? The reason I ask is that is exactly how my barn is made. But it is only 30' wide.

[kitfoxnick]

Let me toss this out there. Are the pre made trusses, sold by Menards, Lowes, etc, made to be used for an open full span roof? In other words, would a series of 40' trusses spaced 24" on center work if supported by some well built walls on three sides? The reason I ask is that is exactly how my barn is made. But it is only 30' wide.

That's how mine is built. I used a stock 4' on center pole barn truss and metal roof with 2 x 4 purlins. Around here a 40' 5/12 pitch stock pole barn truss are around $125.00. I have $2500 total in my hangar materials with no doors. The pole barn suppliers will cut the metal to whatever length you want. I laminated two truss on the open end to support a future door.

I'll see if I can dig out a pic.

[Av8r_Sed]

Kurt,
The ground snow load for your area appears to be 3.0 kPa (63 psf) from the following document:
http://www.cariboord.bc.ca/uploads/8...s_Overview-pdf

You can then plug this and other data regarding your roof into an online calculator: http://www.had2know.com/househome/ro...alculator.html

Using some assumptions about your roof and the ground snow load I get an estimate of 37 psf snow load for your roof. If your roof was 40' x 40' that would give a load of 59,200 lbs. It looks like each of your beams could be supporting as much as 10 tons.

[Kurt.A]

Kurt,
The ground snow load for your area appears to be 3.0 kPa (63 psf) from the following document:
http://www.cariboord.bc.ca/uploads/8...s_Overview-pdf

You can then plug this and other data regarding your roof into an online calculator: http://www.had2know.com/househome/ro...alculator.html

Using some assumptions about your roof and the ground snow load I get an estimate of 37 psf snow load for your roof. If your roof was 40' x 40' that would give a load of 59,200 lbs. It looks like each of your beams could be supporting as much as 10 tons.

Paul,
I had a look at the document and the online calculator. My location is Southern Cariboo District, so the snow load goes to 57 PSF. The area of the roof is 1176 sqft (42 X 28 ft)with a 22 deg pitch. I inputted all the other details from my hanger and area into the calculator and came up with a total Max snow load of 48,180 lbs. How do I calculate the dispersal of the load? My guess at that one would be 1/2 of the load for the beams, with the other 1/2 being carried by the perimeter posts and walls. If that assumption is correct then the 2 beams would be sharing 25,000 lbs. at Max. or 12,500 lbs. each. Now that we have these numbers can the design of the beams carry this load?

[Av8r_Sed]

OK, I think you have a good estimate for the numbers. This is where you need the structural guy to look at the beam design. Most architects have a go to structural engineer so they're not too hard to find.

[Danzer1]

Roughly speaking - the back wall and front beam each carry 25% of the load and the center beam 50%. The loads you mention are only the snow loads plus the weight of the roof itself.

Also important are the size of the joists, their spacing and length of span.

Just a thought on the string deflection measuring - I would use good mono-filiment fishing line. Most regular string will not get taught enough to be straight before breaking.

Greg