In-place retrofit/reinforcement for sawn lumber DFL roof beam failed in horizontal shear?

[Engineerataltitude]

I am working with a condo project located in CA in the Sierra that has seen huge roof snow overload conditions this winter. Roof was designed for 135 psf of snow (about 5.4 ft of snow) and had 12 ft of snow on it when the beam failure was noticed. The 8x14 roof beam has a longitudinal crack at the neutral axis of the section almost the full length of the beam. Fairly deep too. Not all the way through but almost. No obvious problems with mid-span bending failure, just horizontal shear.

I'm trying to work out some kind of minimalistic way to retrofit vertical shear reinforcement (something like the shear ties in a concrete beam) into this wood beam.

Is that a realistic approach? Any ideas? Any products?

 

[Ron]

JAE's solution is a good one. In addition, you could fill the crack with Sikadur 32 or similar epoxy prior to pulling the lags up tight....then you have the benefit of epoxy repair and the lags.

 

[Engineerataltitude]

buildings are in Mammoth Lakes CA, elevation 8000ft. Current official measured ground snow weight is 323 psf, last time I looked. There is a snow pillow measuring station nearby. Design ground SL is 300 psf. Normally that amount of load over design should not create a problem because last time I checked with NDS (about 6 years ago) the average margin of safety to fracture failure of Douglas Fir Larch (which is what we use around here) is about 2.2.

We got several rain on snow events in January and February and the roofs are carrying serious ice layers under very saturated snow. From what I have seen 12-18 inches of solid ice at the eave is pretty typical. That doesn't include the very substantial weight of huge dripping eave icicles. That is an additional 57 - 86 psf minimum of roof load to a roof already carrying many feet of snow. Its also cold now and nothing is melting off. Very atypical for this region. The snow pillow measuring station says the snow is weighing 19.5 lb per vertical foot. But that doesn't include roof ice.

 

[Engineerataltitude]

Here are some cool pictures of big roof snow loads taken recently...

 

[Engineerataltitude]

and another...

 

[OldBldgGuy]

Look at SFS Intec's site. I'm not connected with them but they will cure everything that ails you. Mechanical reinforcement is simple to design and install; think stirrups in a concrete beam.