Hoisting an I-beam …

[radair]

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Are you concerned with the notch on the tension side of the rafter?

No, it’s standard practice to notch the tail end. What’s the difference if one or both ends get notched? Most of the tension (bottom side) and compression (top side) occurs out in the middle, not at the ends. </font>

The difference is the tail end has full bearing on the wall plate, so the notch (bird's mouth) does not change the load carrying cross-sectional area of the rafter.

The detail you have at the ridge reduces the x-section to the thickness measured from the notch. While tension due to bending moment is greatest in the middle of the rafter, shear is greatest at the ends. This is not a good detail. Maybe you have no significant snow loads to be concerned with, but I would never recommend it.

 

[Fungus]

I’m not recommending anything, I’m just reporting on what I’m doing with my tractor /forums/images/graemlins/laugh.gif

On a more serious note, it may not be obvious from the pictures I’ve posted but the ridge notch is actually less than the plate notch (see attachment).

Yeah, I’m not that happy with this connection scheme either. It was a compromise between several factors. Our snow loads are only 10 to 15 inches. My dead loads place about 152 lbs on each rafter or 76 lbs on each notch. With a full snow load (dead + snow) it increases to 479 lbs each rafter or 239 lbs each notch.

Using No. 2 DF (2 X 6, 16” OC, 12’ span) I’m confident this building will be around longer than I.

Since I’m planning another building using a steel ridge beam I would appreciate any input on a better connection scheme.

Thanks

 

[Fungus]

Update picture: Finishing up the sheathing

 

[Fungus]

Update picture: Completed view from below

 

[Fungus]

Update picture: The gable end

 

[Fungus]

Update picture: Roof completed, just need to stick on the ridge vent.

 

[EddieWalker]

It's looking really good! I really like the three doorways. That's gonna be a great feature.

 

[sneaky_pete]

</font><font color="blue" class="small">( It's looking really good! I really like the three doorways. That's gonna be a great feature.)</font>

I agree on both counts. You can never have too many bay doors. I have two and wish I had three in my shop.

 

[Henro]

<font color="blue">On a more serious note, it may not be obvious from the pictures I’ve posted but the ridge notch is actually less than the plate notch (see attachment).
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Fungus,

That is a great job you are doing there. Personally I doubt you need to worry about the notch at the ridge. A smarter guy than I could calculate it, but when you think about it, what is the normal failure mode of beams? It is not shear at the ends, but tension failure in the middle. If you need reassurance, notch a rafter like you have, put it between two blocks and push down on the center with your loader...until it breaks and see where it fails.

That being said, the notch at the lower end is not the same as the notch at the ridge end. The lower end notch is a non issue since the rafter is resting on the top of the wall. At the lower end the notch does nothing to weaken the rafter. The upper notch does weaken the rafter, and the question simply is how much?

Anyway, my bet is that it will be a cold day in heaven before you have problems with your roof, as far as snow load goes, everything else being sized correctly.

That is a fine looking building you have there.

 

[Fungus]

OK guys, I’m not getting it. Why is the notch at the plumb cut weaker than the notch at the plate /forums/images/graemlins/confused.gif