Snow Broke my FWC Hawk Roof

[pods8]

Has anyone seen this failure pattern before???

I haven't over the years but doesn't mean it can't happen. I think him concentrating the stresses over those crossmembers was a unique and unfortunate combination.

 

[pods8]

a design/material flaw in the FWC...looking at how the round strut is cut into the rectangular support just does not look right; seems that would induce a weak/failure spot...

They have been built like that for 40+ years (I can show you a 1982 roof frame right now if you'd like), also if you noted the build photos from ski3pin ATC does it too.

 

[Vic Harder]

And this is the first? Failure I’ve heard about, so chances are it’s an unfortunate fluke.

 

[Corn Husker]

I noticed in one of the pics Salmon posted on July 17 it looks like there's wood inside the broken roof bow. I wonder why fourwheel camper would be putting wood inside of them.

 

[Wallowa]

Corn,

I don't see any wood inside the roof structure. What did I miss? Longitudinal Wood strips hold the liner to the top inside and the transverse board in photo is used to push top up into place

 

[Corn Husker]

The pic of the broken roof bow where the conduit goes through. I believe you have it labeled as inside break close up. There is definitely wood inside the broken roof bow.

 

[Corn Husker]

 

[Wallowa]

Good eye! Perhaps the wood is there to provide a purchase for fasteners? Like wood strips? Lights?

 

[JaSAn]

This is as far as I could magnify it before it started to pixelate:

It looks to me like the discolored back and bottom inside of the rectangular crossbeam. What I am pointing to would be the inside bottom of the beam.
Could be wrong; my eyes don't work well at this time of night.

 

[ckent323]

That photo appears to show that a notch was cut into the square tubing and that there are no welds there. I think I see a fastener in the middle. Is that a horizontal piece of metal conduit? What is that for? Is it factory?

Notching the top of the tubing would weaken it. The screw coming in from the bottom could be a crack initiator. Downward force and the notch could allow the tube to buckle and the screw hole could lead to the metal splitting or tearing.

A closeup better resolution photograph would be informative. I would have a structural engineer look at this if you know one.

Floor joists and roof rafters in houses are not allowed to have notches because they can buckle under load.