Bridge and more, help and suggestions.

[paintman161]

So i have two summer projects i want to get done. Both will allow access for my tractor (ford 1900) and bush hog.

First I have an old abandon railroad bridge that i want to fix up to get my tractor across to maintain the other side of the trail. Some of the railroad ties are rotting or rotted out, i was thinking of replacing them with new wood thinking 8x8 (about the size of the old railroad ties) but not sure of the wood type? Want something that will last for a long time and most likely be rough cut. Should i rip up all the RR ties or leave the ones that seem to be good. Also going to add 2x10 rough cut perpendicular to the rail road ties for a decking.

Next project i have is a 2 large culvert pipes that used to be used for crossing a large creek, the top is missing and only the culverts are left. I was thinking of adding fill or something to create a new roadway over it, but not sure what fill to use and how to stop it from getting washed away. I have a bunch of old large chunks of concrete right near by to use. (assuming it was used for the old roadway over the culvert pipes.)

Any ideas would be most helpful and pictures are below.

 

[bcp]

Old ties that seem solid may be rotted out on the inside. The outside inch or so is creosoted and firm, but water gets inside through cracks and spike holes and rots the inside.

Bruce

 

[paintman161]

so you are saying i should replace them all. If this is the case should i redesign it? Since there wont be any more trains going across it i can probably reduce the number of cross ties.

 

[Dr Dave]

The culverts, look like a good location, for some hydro power

Dave

 

[CliffordK]

Perhaps plank it with something like 4x12 or 6x12 planks.
Definitely pressure treated, or creosote treated.
I would probably do tighter spacing without "tracks"... perhaps space 3/4" apart or so, enough that they can breathe a little, but close enough that animals could safely walk across it.

Any way to take your tractor around the bridge rather than over the bridge?

As far as the culverts, definitely fill in before driving over them. Does the creek overtop the culverts? Rip-Rap along the sides, then fill the middle with gravel and dirt. Or, you could build forms and pour concrete along the sides.

 

[rbtjr]

My 2 cents worth (if worth that): First, as to the pipes, we have an almost identical bridge, with 2 36" galvanized and aluminized pipes. One got crushed due to loggers coming too close to the end of the pipe, but that wasn't the fault of the pipe or the design. We had the bridge designed by an engineer. We covered the pipe with 2' of dirt. We compacted the dirt after we got a good cushion on top. The compaction of the dirt between the pipes is important. It provides a support in the middle that is stronger than the pipes. I see that one of the pipes looks like concrete. Good. Better strentgh, I think. So, if it were my project, I would cover the pipes with 2' of dirt, or more, and I would drive over the dirt multiple times for compacting. Next, on the water sides of the pipe bridge, you will need to protect against erosion. We did that by covering the dirt with geotech cloth, which will last a long time, and we piled rip rap on top of the geotech cloth. The combination holds up very well against hard-rushing water in flood conditions.

As to the RR bridge, it looks to me like you have two issues. One is to preserve the metal. I don't know how to do that, but I would try to do it, and I would employ a civil engineer to come out and take a look, and give me some advice about how to do it. In fact, I would employ a civil engineer to come out and provide advice about both projects. Second, I would for sure replace all of the RR ties with new ones. I agree with the poster above about the deterioration inside the ties notwithstanding the creosote on the outside. You will put space between the ties so that water is not captured on top of the ties. It's easy for us to say, but I would put something else on top of the ties as well, maybe treated lumber. I can't tell from the pics what the width between the metal supports is. Hopefully that width is about what your tractor tread is. If so, your project is obviously easier. One thought is that you could lay two courses of treated 2 X 12s or so length-ways along the path your tractor wheels would follow across the bridge. I would leave maybe 1" or so spacing between them for water to drain through, and I would put treated wood shims on the outside edges of the two courses of treated wood to raise the outside edges slightly, maybe 1/2" or so, to cause water to drain off the treated wood to the 1" space on the inside. You could of course put the shims on the inside of the two courses of wood, but that would create a little hump in the middle, and it would be easier to drive your tractor across if there were a little depression in the middle versus a hump in the middle.

Like I said, just my 2 cents worth.

 

[paintman161]

We just had a warm up in temp so some of the snow has melted down and this is why the water is high on the culvert pipes. But it also makes me wonder if we get a lot of rain or have a quick thaw that the water may go over the culvert pipes. (the one covered in concrete was actually clogged by debris, so i am sure that was not helpful.) I like to fill idea 24" and then using rip-rap, which i may just use the old broken up concrete for.

As for the old train bridge, this is my only access to the other side of the property. I figure if those beams could support a locomotive it should have no issue supporting a tractor. I am going to see if i can find some new railroad ties to replace the old ones and space them about 1" apart (which they are now) and then add a 2x10 layer of wood over that and leave like 3/4" spacing between for water and snow the shed off of it plus i am going to add some railing to the sides. As far a preserving the beams i am not even sure who i would contact that, maybe i can give the highway dept a call and see who they use.

 

[Ranger Rick]

I used to work on a rails to trails park that reused the old railroad bridges. In our case treated 6x6's were used for the decking. They were probably spaced about an inch or less apart. A metal plate was bolted on the bottom of the 6x6 and overlapped the flange of the steel beam. This kept the 6x6 from moving very much. We would drive truck and tractors over them all the time. No additional decking was used. Over time the bolts would loosen and someone would have to get under the bridge and tighten them up again.
On the culverts it looks like the stream goes over them occasionally so you should put in an additional culverts or build it so that water can go over it like a low water bridge. If you just build it up a couple of feet the water will back up until it does go over the roadway. Rick

 

[paintman161]

Thanks for the info. I wont be driving over it a lot with the tractor maybe once or twice a year most likely using the ATV or just as a person bridge. If i get some 6x6 treated then put 2x10 treated on top of that that would still be pretty strong and i would be able to stay at grade on the ends of the bridge. It will just come down to if i can find some railroad ties or not. Thanks for the idea!

 

[CDN Farm Boy]

As for the steel girders, clean the dirt away from the ends and don't worry about them. They'll still be there and plenty strong in 100 years.

For the decking on top, if you plan to run boards length wise as a top layer, I wouldn't be putting the 8x8 that close together unless you only run the lengthwise boards on the tire track areas. If you fully deck the top with 2x or thicker lumber, if it were mine, I'd leave a 12" or so between the 8x8s. Only leaving 3/4" of an inch will certainly make for a stronger bridge but will also be way overbuilt than need be for a CUT and foot traffic.

The shim idea mentioned above, while a neat idea, to me seems like WAY more work than what it's worth. If you are concerned about water sitting on the deck boards, make sure you install them with the grain of the wood like a U (look at the end grain) When wood dries, the growth rings try to straighten out giving a slight crown on the top of the board shedding the water. If you install them with the grain like an upside down U, they may dry to hold water, but not much.

If you run one of the 8x8 extra long every 6 or 8 feet sticking a couple feet out each side it will allow for bracing of sides/handrails without impacting traffic on the bridge