need to build a bridge

[Metals406]

The stringers for that bridge were 30' long; I think about 6X16. I used three stringers. Width between the rails was 6 feet, to accomodate horses (they don't like being fenced in between the overhead truss pieces).

Built this one on the same trail, same gig with the sawmilled lumber pieces, but it was "only" about a 2.5 mile hike. 32' stringers, 6x16 again.

Edit: the interesting thing about these bridges and doing them that way: when we first went through and built the trail in the spring, we could not run power equipment due to noise restrictions for nesting birds. So when we had to saw through the logs we used crosscut (hand) saws. It's where I learned to file crosscut saws; spend an hour or so pulling a dull crosscut and you'll be motivated to learn to file them.

Upshot of it was, we were working on a fairly steep hillside, so we had to go quite a ways uphill and downhill of the trail to find a place to safely stand to run the hand saws. Consequence of that was, we cut the logs about 30 feet (and one of them 32') long. Pulled them out of the way and built trail.

Come winter, we could run power equipment, and carrying in an Alaskan mill all that way just seemed easier than packing in the lumber.

Who did the structural design for your bridges?

 

[rtrsam]

Who did the structural design for your bridges?

I referenced stringer size charts from some old USFS manual I had. The same manual showed the basic design for the overhead truss assembly. I adjusted the size for the requirments of the creek I was dealing with.

The basic structure, however, is sized and based on experience and on previous similar structures I have built. The big caveat is that the home made timbers were not graded by a licensed timber inspector for structural use. Sawing up old fallen logs is always a little suspect, and expecting them to function for structural purposes...

I can say that the timbers I used were quarter sawn to provide a vertical grain, and free of visible rot or cracks, with minimal knots.

Overall, my guess is that the thing is WAY overbuilt. I've put loaded track toters on them (close to 4000 pounds) and it felt like driving them on a concrete slab; no sway or groans or bounce.

 

[HuskyMike]

the area I am doing this is the only spot I can use, level and narrow . but the banks are steep. 90 deg and 3 feet deep.

I have the exact same thing on my property!

 

[Metals406]

I referenced stringer size charts from some old USFS manual I had. The same manual showed the basic design for the overhead truss assembly. I adjusted the size for the requirments of the creek I was dealing with.

The basic structure, however, is sized and based on experience and on previous similar structures I have built. The big caveat is that the home made timbers were not graded by a licensed timber inspector for structural use. Sawing up old fallen logs is always a little suspect, and expecting them to function for structural purposes...

I can say that the timbers I used were quarter sawn to provide a vertical grain, and free of visible rot or cracks, with minimal knots.

Overall, my guess is that the thing is WAY overbuilt. I've put loaded track toters on them (close to 4000 pounds) and it felt like driving them on a concrete slab; no sway or groans or bounce.

Right on... They look really neat, so I was curious if you designed them, or someone else did? You did a great job.

 

[Kansas]

If you don't build something like this you're missing an opportunity for some fun. I built this one four miles back in on a trail a couple years back. Packed in an Alaskan Mill and saws to make all the timbers from fallen logs we'd had to cut off the trail. Deck boards are split product, mudsills are spllit. Some of the retaining wall stuff we just used whole logs.

An eight mile round trip foot "commute" convinces you to come up with novel ways of doing things with stuff you have on hand. At least it was only uphill one way...

I'd like to do something like this just for myself someday, be a little more experimental with using smaller dimension wood.

That is amazing what a great job that bridge is just awesome! I never saw anything like it and it looks hell for stout too good work thanks for sharing!!!

Kansas