Tractors and wood! Show your pics

[Oldpath05]

I put some used oil on the first panel and let it set for a few days, this is where pressure treated timbers would be better. I started with a brush but after a hour it seemed like I wasn't getting anywhere.......

 

[Loaderman22]

I put some used oil on the first panel and let it set for a few days, this is where pressure treated timbers would be better. I started with a brush but after a hour it seemed like I wasn't getting anywhere...

Sounds like you will do just about anything to get rid of that used oil you've been collecting, run it for bar oil, build a bridge to coat it with, what's next, soak your winch cable in it to keep it from rusting, or sell it as driveway sealer?

 

[Jstpssng]

Nah, just trying to give OP a hard time. He's doing such a great job on that bridge section, I don't want it to go to his head, then he will need the 16' door just for his ego.
"Good" friends of mine just out in a pool. They haven't invited me over there yet either. Hmmm.

Good idea, it's always good to plan ahead. :laughing:

 

[Oldpath05]

Since I built the bridge panel bottom side up, the first and last time, I decided to flip it over near the shop before trying to flip right side up in the woods where room is limited, well it was heavier then I thought, had I could do to turn it. So when I did get the panel off it fell back on my bunks almost knock them off, they just sit on the trailer so it dont take much to move them, I had to un-screw the runners and set them back in place, the good news is nothing broke and I did find a loose screw.

 

[CADplans]

This is the "bridge panel" they used at my place,,
over 160 loaded tractor trailers crossed the bridge,, all over 80,000 pounds,,
They were so heavy, they could not go on the interstate,,

Steel, not wood,,

 

[Oldpath05]

Now lets try this again so my eggo will fit through my door........

What really upsets me is, I had the video on but didn't push record. that panel went up slick, so I'll let this panel sit for a few days see if the oil will soak in. Now I'll start the next one, this will be panel two for those that lost count and get to much pool water.......

 

[Oldpath05]

This is the "bridge panel" they used at my place,,
over 160 loaded tractor trailers crossed the bridge,, all over 80,000 pounds,,
They were so heavy, they could not go on the interstate,,

Steel, not wood,,

Thats a unique design, in the logging business they need a heavy duty bridge, bet that cost a pretty penny.

 

[Jstpssng]

Thats a unique design, in the logging business they need a heavy duty bridge, bet that cost a pretty penny.

There are a couple here which are owned by the Maine Forest Service and loaned out to various contractors. I had one on a job down off the Airline a couple of years ago. The wooden skidder bridges similar to what you are building are more popular though, although generally made from 12x12s. We can bridge a small stream for about 3K, using concrete waste blocks for abutments.

 

[Skeans1]

This is the "bridge panel" they used at my place,,
over 160 loaded tractor trailers crossed the bridge,, all over 80,000 pounds,,
They were so heavy, they could not go on the interstate,,

Steel, not wood,,

Are those old rail cars? If so they’ll do 80k for a while but much more they don’t do so hot.

 

[Skeans1]

The Vermont Dept. of Forest, Parks, and Recreation has been pushing portable skidder bridges for loggers for some time now. They are very similar to what Oldpath05 has built. They have published some designs here: Temporary Wooden Skidder Bridges. Their "standard" design is 20 feet long and built in 3 sections from 6"x8" #1 Grade Eastern Hemlock. It is designed for up to a 14' clear span. The max load rating is for a 32,000# skidder under full load, or a 50,000# forwarder fully loaded. (It should be noted that in addition to the 6 through-bolts, these bridges also connect adjacent beams using 10" flat head log cabin screws midway between each through-bolt. This helps further stiffen the bridge and assure that loads get distributed among adjacent beams.)

I'm no Civil Engineer, but it certainly seems that as long as the wood is sound, OP should have no problem with his +/- 6000# tractor.



When the portable skidder bridges I mentioned above are used, they generally drop them right on the ground. Generally, getting wet isn't what makes wood rot, it's failing to get dry again. Since they are pulling the bridges at the end of the job, they usually have plenty of time to dry back out again. Also, since they are regularly moved, they have easy opportunities to inspect the panels for excessive rot or other damage.

With the light loads and short span OP has described, he should be OK for years. However, It might be worth considering putting some sacrificial wooden footers under each end and making a dirt ramp up to the bridge. If the footers start to go, you can always replace them. If you use something highly rot resistant for the footers, you can get even longer life (Black Locust will far outlast Hemlock in terms of rot resistance. A concrete "jersey barrier" or cast block can also make a great footer.)

I made a little footbridge over a small stream years ago by just free-hand chainsawing 3 hemlock logs into beams and lag bolting them together. I put each end on a short length of 6"x6" Hemlock beam, which was in a wet, muddy area. I had to replace the Hemlock footer after about 8 years. The bridge itself was still fine 15 years later when I pulled it out to replace it with something less beefy, but with better footing (my neighbor's almost completely blind dog had trouble with my log bridge, so they made a nicer plank one so she could still handle their walks).

EDIT - added PDFs of the "Standard Duty" temporary skidder bridge designs. If anyone wants the heavy duty design (uses 6'x10' hemlock beams) let me know.

Just figuring a 50k empty forwarder is a 20 ton or even 25 ton load capacity forwarder that sure seems a little light on materials.