I have run into this case on numerous ocassions and want to make sure I'm looking at it correctly. I have an existing 4x12 beam that needs to be reinforced for a new loading. The new load produces a moment of 1763 ft-lb, and I will support this by sistering a 2x8 on either side of the beam. My question comes with the nailing required to make this beam act as a single unit and adequately resist the loads. I've gone through the horizontal shear calculation, but am not quite sure if this is the correct way to go about it. All examples I have seen assume that the beams stack on top of each other instead of side by side. I have attached my calculation so please take a look and let me know what you think. A few main questions.
1. Can I even use the horizontal shear equation when they're side by side?
2. Do I need to worry about the connection so much when they are side by side? I can see the merit when they stack vertically, but feel like they should act together with minimal nailing in this case. Maybe 2 rows of 10d at 6" o.c. staggered.
What is making me question myself is the 371 lb/in I am getting. I would need an excessive amount of nails to satisfy this shear when the extra load the beam will take appears to be rather small. Any thoughts?
1. Can I even use the horizontal shear equation when they're side by side?
2. Do I need to worry about the connection so much when they are side by side? I can see the merit when they stack vertically, but feel like they should act together with minimal nailing in this case. Maybe 2 rows of 10d at 6" o.c. staggered.
What is making me question myself is the 371 lb/in I am getting. I would need an excessive amount of nails to satisfy this shear when the extra load the beam will take appears to be rather small. Any thoughts?
