FnC, I am at the mercy of others on my info.It is definitely hard to beat "hedge". That's what we call Osage orange around here. That is some wicked stuff. I see sparks flying of the chain when cutting it with a chainsaw.Is it a big deal to mill that type of wood? I assume it would be cut with a bandsaw?
Give a man a fish, and he will eat for a day. Teach a man to fish and he will sit in a boat and drink beer.
I would say if this is what he wants to do to go with 4 X 4 joist at 16 - 18" on center depending on his length of planking. This gives him a way to attach the joists to the steel beam. It would be difficult to attach 2 X stock to the steel beams and they would have a tendency to rotate or flip. Also when installing the planking make sure he staggers the joints like you would when installing random length flooring(I don't think 4" wide is enough to butt pieces together and nail them in, especially with hemlock that is brittle/weaker) It would also be a good idea to run a 4 X 6 along each edge to act as a wheel stop.
You will have to let us know how the hemlock holds up over time. Hemlock is not a strong wood, and there seems to be different opinions on it's resilience to rot. I certainly would make sure those 4x4's are strong and out of something else besides hemlock. I don't think it will last 50+ years.
FnC, I am at the mercy of others on my info.It is definitely hard to beat "hedge". That's what we call Osage orange around here. That is some wicked stuff. I see sparks flying of the chain when cutting it with a chainsaw.Is it a big deal to mill that type of wood? I assume it would be cut with a bandsaw?
I use a small bandmill, and Osage is a #@!* to cut. A lot of it is how the blades are sharpened with hook, set, etc.
I had one customer bring me a wood from south America, can't remember the name of it off hand. It was only about 4- 5" in diameter and 3-5' long. A whole dump truck full of it at a time. You would saw it and when you get to the last 1" of the cut, it would crack the rest of the way to the end. It sounded like a high power rifle going off. That was always fun to do when someone was around and not expecting it.
So i may have found a place that sells decent railroad ties, a small local lumber yard has them at $21.99 each and they said they are clean on all four sides (not sure what this means). I am going to look at them tomorrow and see what they have and how solid they are. If I can go with the RR ties I can put a 12" space between them and use the decking over that which would give me plenty of strength that I would need. As for treating the hemlock, my friend says he know of a way to treat them using old motor oil and diesel.
If I have to go with using P.T. SYP it would be no less than 6x6, just so i would have more of a nailing area for the decking. I do plan on staggering the joints as well.
Here is something else that you might figure into the mix. With the possibility of the hemlock going bad, have a second plan in place in case it does. Find out size and type your using. Put them on centers in such a way that if the hemlock fails, you could tear the hemlock off and put more new joist in between what is already there and you would be good to go with a solid deck. Just leave a bit for wiggle room to get them in, make sense?
I wont be using hemlock for the joist, i want something to last- if the RR ties don't work out i will use 6x6 PT for the joist. I don't mind using the hemlock for the decking since it will be a lot easier replacing a board then having to tear up the whole thing to replace a joist.
I suggest putting the 2x10's at 45 degrees to the 6x6 joist. This will distribute the wheel load of the tractor better. Years ago I worked on a couple piers that had trucks driving on them to unload fishing boats. That is the way they did it.
I'm no engineer, but I wouldn't be afraid of those in your application.
"Forget pounds and ounces, I'm figuring displacement!"
If we accept that: MBG(+)FGSF(=)HBG(F1) And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1) Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT? PB answer: It depends.
This brings you full circle. Back to RR ties and what is there now. Consider evaluating what is in place. Replace the bad ones and plank over.
It's obvious from your initial pics that some of those need replacing. I would take a nail(in a comfortable handle) or an awl one size smaller than the nails you will be using to build. Go over each RR tie that you check on the bridge or that you buy. If good/new 4x4's are strong enough, then 6x6' that have been used and still solid should be good to. Couple this with the fact that if you keep the spacing the same as what's on there, and the planking on top of it, it should be as good as recommended or possibly better.
One way you could test them, but at a lot of extra work. This would test them structurally, which is a bit different soundness ( nail test). Both things are needed for your application. Place some beams 8' apart on the ground. Lay out the RR ties across them (not fastening)making a solid enough deck to drive on, but enough space so that each one has some wiggle room, just RR ties no planking. Drive your tractor across. Any that you even hear cracking or bending more than the average, replace. Roll the ties over 180 degrees and repeat. Possibly worth the effort....
And as I said, work safely. Some of those old ones that are on there can give out it a blink of an eye.
they all will be replaced, i am not taking any chances with the old ones, who knows how long they actually have been there. Thanks for all the help. Once this rain stops and it dries out this will be my next project.
I'm glad it's going well for you. Thank you for keeping us updated.
I am curious about the water this goes over. How far down is it, and does the water ever rise? Are you going to take advantage of that water for a pond?
It is about 20'-30' to water level (depends if we have a heavy rain. The water does raise to about half the wall after a large thaw or a heavy rain. We will not be using it for a pond or anything since when it floods it would flood everything. We will be digging a separate pond else were on the property since we need it for fill for our driveway and house area.
Here is the finished bridge. Just need to coat the top with a sealant which i will be getting from my Father in law, (says he has some really good stuff that penetrates deep into the wood).
"Forget pounds and ounces, I'm figuring displacement!"
If we accept that: MBG(+)FGSF(=)HBG(F1) And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1) Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT? PB answer: It depends.
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