I would say to think of any fastener as an added safety precaution. Structural support via gravity is much more important and the basic principle of sound structure. One has to consider movement prevention too- thus things like hurricane strapping to reduce wind effects etc. When one support a piece of lumber by laying it on top of another- as you would have seen in timber frame construction, notching is a big factor in providing necessary structural support. Fasteners themselves are not enough to overcome shear strength issues; for instance nails, bolts etc. So whatever you can do to reduce the effects of things like snow load wanting to shift the position of your rafters, or any other component of your pole barn the better. A beam is best if it has its load centered over it so that the downward force is only down and not able to move sideways or bow out away from the beam, as one example.
For the size of the pole barn you are building I would at least consider consulting with a structural engineer or at the very least a lumber yard's designer( cad/cam drawing tech) to possibly have some drawings done to help plan out what makes most sense from a structural aspect. I have had this done several times, and it can be very useful to help think things out on paper prior to doing them in the field on a trial and error basis. Especially on the scale you are talking about. It is not too costly to do this, and most larger lumberyards provide this type of service for an hourly rate.
And as to overkill- I would tend to overkill the heck out of that structure, especially with the weather weirdness we have been experiencing over the last few years. Its easier to overkill now and have the building stand for a long time than to try to retrofit later if problems come up. You could also contact any truss company and they can tell you what the snow load factor is in your area- as another factor to build into your structure.
I have the exact same saw and it is AWESOME! I bought it from a guy who was buying another saw at our local dealer, when one of mine was biting the dust. We got talking and he showed me the saw- which he planned to keep as a backup, and I offered him cash and we made a deal- I like it best of my assortment of saws. It cuts wood like crazy and it is light weight too.:thumbsup:
One last thing- look for star drive(Torx) lag screws. They are awesome and will really add some strength to whatever you have to pull together. They are available in various lengths. They also make ledger bolts that are equally as strong and will not cam out. Some have hex heads and some are star drive. You can drive them with oscillating drive drill/drivers or with hammer drill/drivers. Either way they will blow you away as to what they can do that you can't do with other fasteners.
