Okay bridge guys...

[SteveP]

Been reading this forum for a while now and absolutely love it- received many an idea to finish my own barn. However I have also noticed that there are more than a few sharp individuals that know a ton about bridges, so I am directing my questions toward you.

I have a creek that runs through the back of our property that after a heavy rain becomes impossible to cross, and takes a while for the water to recede and be able to cross without having to don waders. I am thinking about building a bridge to make life easier, but have a few concerns.

Where I plan on putting the bridge is about 35-40 feet across and will be about 6-8 feet to the bottom of the creek. Would like it to be wide enough and strong enough for a side by side ATV. My idea is to use 2x somethings, laminate them and put them 6-8 feet in the ground as posts, similar to the posts in a pole barn. Then I would use 2x somethings, two per beam, bolt/nail/screw them together for the deck supports, one on each end then one in the middle. Finish the deck with either 2x's or just use the regular deck flooring material.

My concerns are:
1) Is this something that will work?
2) Will this be strong enough, not only for the ATV but also against any possible water force that may be pushing against it during a high creek?
3) What size 2x's should I use for the posts and also the beams?

Thanks for any input you guys have. You are the bestest!!!!!!!!!!!!--Steve

 

[pixelmonkey]

need some info...

1. what is the soil condition? grass, swamp, rock, mix?
2. ever consider steel?
3. check with local gov. i know a few in Oklahoma that have removed steel bridges and offered them free if someone would take and transport them away
4. erosion of the sides? creek "bank" will be a HUGE problem
5. know the weight of the side by size with people? loaded? *best to build a bridge too strong than weak*

for the length of the span, i would recommend steel for the main connections.

if you have photos of the crossing and a few more measurements, i know people here can help.
chris<pixelmonkey>

 

[W_KY]

I'm no "bridge guy" but what about using concrete posts (using the circular cardboard tubs as forms). I'd think you could sink those 3 or so feet in the ground and they wouldn't go anywhere. In my opinion, it all starts with having a solid foundation that you can build upon and not have to worry about. I'm sure some engineer on here can explain why I am incorrect in my thinking.

 

[Steevo]

Notice that when you travel around, you always see old bridge abutments/piers/etc. where the old bridge has long since washed/decayed/burned away.
Good solid concrete foundations at each end, protected from wash-out, are the most important part. The rest can be built with logs, poles, steel beams, an old railroad flat car, or whatever.
If you live in a state where they allow you to excavate/pour at the edge of a creek, you are fortunate. Many states no longer permit for things like this without all kinds of enviro-**** to assess the impacts on the frogs or birds, or gnats.

 

[SteveP]

One side of the creek is mostly grass, with the other side wooded. The area where the bridge will be located is heavily wooded, thus my thinking of 'piecing' a bridge together; getting a preassembled unit there will be impossible.

I think erosion will not be a problem where the bridge will be located; one side is rather steep and the other kinda flat. I also was going to place the posts far enough from the water to prevent/diminish any problems.

I did think of using concrete for posts, but thought perhaps it would be easier to sink a wooden post and not have to deal with the concrete. Another concern I had with the concrete was how to attach the beams to the concrete. With the wood, the beams would be sandwiched inside the posts.

I also thought of getting steel for the main portion, but again would have difficulty getting them to where they need to be.

 

[lawfarm]

Simplest solution: Find an old flatbed semi trailer, 40-53' long. Cut the axles and dolly off. Excavate and build a solid foundation to place it on, on both sides, along with appropriate ramps to get on/off the trailer. Paint to taste. Voila.

If getting it into place is an issue, leave the wheels on until you have it across the creek, and then cut them off.

 

[buening]

I too recommend an old flatbed semi-truck trailer or railroad flat car if you can get them. That kind of span may be a bit too much for old telephone poles unless you group numerous ones pretty close together.

It sounds like you are attempting a glu-lam beam. These can be purchased if you are interested in going that route, but they need to be treated since you are using them outdoors. I personally wouldn't recommend it with that large of a span. A concrete footing is highly recommended due to the span. If erosion is an issue with the stream, you may have to get some old concrete chunks or riprap from a local quarry to protect the concrete foundations.

Army Corp should probably be contacted to let them know that you are building a bridge across the stream, especially if the location is within a FEMA Flood Map location (google them and you can view interactive maps to verify).

 

[Torque1st]

I lnow this is not what you want to hear but... Check with the local gov't officials and the Soil and Water Conservation dept DNR etc. There will be a number of permits from various gov't agencies required. The penalties for going without the permits can be severe including major fines and "federal pound me in the a$$ prison" time. The permits will probably also require a PE stamp on the plans. Anything near a waterway is not cheap.

 

[buening]

Looks like I took too long to reply LOL.

See the following link for glu-lam span tables. http://www.cascadesl.com/CSL Design Guide.pdf

Page 11 shows a 5 1/8" wide by 15" deep glulam can support 50 pound per linear feet per foot width of deck. If you use 3 beams at 3' centers, you would be allowed less than 17 pounds per linear foot of beam. I can't go into details due to my profession and liability reasons, but if you decide on building one yourself I'd suggest contacting a local structural engineer. If this were a 20' span then no big deal, but 35'-40' can be a stretch with home-built materials.

In regards to using sono-tubes to pour concrete pier columns, that would only work if you pour a concrete spread footing to support these columns. Without the footing your concrete columns would just settle in the streambed muck or would eventually scour around them and then settle.

 

[sungrove]

Looks like I took too long to reply LOL.

See the following link for glu-lam span tables. http://www.cascadesl.com/CSL Design Guide.pdf

P

buening, ( edit, sorry buening, I read your second post but not your first where you mention that the glu-lams would need treating, this works? Neil )

wouldn't the glu-lam sellers counsel against using glu-lam beams outdoors like this since they would tend to delaminate ?
When I was rebuilding part of my house I ventured to use a glu-lam beam which was great. But I remember Weyerheauser company reps not wanting me to even expose the ends to the weather. I also notice that when local buildings here are built using them they do expose the ends to the weather but cover the end with metal flashing.

Thanks for helping us with these questions buening.

Neil

 

[1320stang]

I'd go old flatbed trailer as suggested above, or a bunch of culvert's and rip-rap.

 

[Bear]

Perhaps a culvert arch where each sides are set on concrete footings but the creek bed is not disturbed.

 

[Torque1st]

The reason Gov't people are not much in favor of makeshift bridges is that when they wash away they can damage or destroy downstream structures and cause severe flooding when they block off the waterway. The bills and fines you will receive for that type of damage can be substantial. The state will also figure out where the bridge came from using those nice satellite pictures. They also use them to spot illegal bridges.

 

[sungrove]

The reason Gov't people are not much in favor of makeshift bridges is (snip) The bills and fines you will receive for that type of damage can be substantial. The state will also figure out where the bridge came from using those nice satellite pictures. They also use them to spot illegal bridges.

Ah, that's the beauty of the the semi trailer idea. You just parked it in the wrong place, sorry about that. Neil

 

[Torque1st]

Ah, that's the beauty of the the semi trailer idea. You just parked it in the wrong place, sorry about that. Neil

I don't think that excuse will fly...

 

[sungrove]

I don't think that excuse will fly...

Ok, I think it's time for an entirely different idea. How about a tunnel? I obviously was joking in my last post... and this one too. Neil

 

[Torque1st]

Hmmm rent a TBM, some concrete for liners, dig a hole, dig all the way to the house... Why stop there? Make a nice underground racetrack. You could really go fast with a circular tunnel for banking.

 

[buening]

buening, ( edit, sorry buening, I read your second post but not your first where you mention that the glu-lams would need treating, this works? Neil )

wouldn't the glu-lam sellers counsel against using glu-lam beams outdoors like this since they would tend to delaminate ?
When I was rebuilding part of my house I ventured to use a glu-lam beam which was great. But I remember Weyerheauser company reps not wanting me to even expose the ends to the weather. I also notice that when local buildings here are built using them they do expose the ends to the weather but cover the end with metal flashing.

Thanks for helping us with these questions buening.

Neil

Some places make them for exterior use, such as http://www.rosboro.com/products/treated.html

Note that they are not made to sit in standing water, like a boat dock.

 

[akdiesel]

Torque1st has a valid point. The Government will make a example of you IF YOU ARE CAUGHT.
As for using wood in the ground fro the supports it wil rot over time especially next to a water source. Try getting ahold of some old telephone poles (oil soaked) if you go with wood supports.
Lawfarm has a great idea of using an old flatbed trailer.

 

[SirPoopsALot]

If there are good sized trees on either end, a steel cable "rope bridge" sort of like this:

Obviously you would want it wider, and instead of rope use steel cable... Might be cheaper

 

[Deltarat]

The flatbed trailer is a good idea if it is legal to put in a bridge. It won't wash down stream and destroy anything. I put in a flat railroad car across a creek back in the 60s and water goes over it 10' deep after big rains and it is still there today. We drove 70,000# trailer trucks across it hauling our soybeans out.

 

[SteveP]

Thanks for all your replys. After reading this I will be making some phone calls/ visiting some county offices to see what I can and can't do. I was hoping to put something together without making a big deal out of it, but like many of you have suggested I would hate to have a visit from the G-man, should something happen. A big thank you to you all.

 

[nissan_crawler]

depending on the size of said creek, you can also build a "texas crossing" (at least that's what they were called in North Dakota).

Take some culvert pipe (you can pick this up for free at all sorts of places), drop it in the creek the full width, then pile rock over them as high as you need to level it off (works great if you have farmers around with rocky fields that use rock pickers). We did this and had little problems, and we had huge ice flows. Now, you obviously aren't going to be driving a car across it, but a pickup/atv/tractor will have no trouble.

 

[little d]

i built a bridge for a friend several years ago, we used telephone poles, and 2by4's(cca). worked great, i think its still there.

 

[Jared]

Id use a trailer of railcar, how driving some piles to support it?

 

[onewaydave]

Might check with the County Extension agent.

We have a creek that is about 5' wide and 3' deep. A 7" rain will put a 30' wall of water down it easy. For years my Grandad was frustrated with the corregated drain tubes 'cause they would plug up with trash and the dam would wash. Big hit in repair costs. So he bought a railroad tanker. Must bee 7/16" steel 6' dia and 30' long. He cut the end caps off and since the dam has not washed. The end cap makes the coolest fire pit for our BBQs. 6' dia and 20 people can sit around it easy.

I like the rope bridge though.

 

[krooser]

My old snowmobile club has built several bridges using old school bus frames for the main stringers and then we finished 'em off with a wood deck bolted to the frames. Works great.

We'd rent/borrow/steal farm tractors, skid loaders, wreckers, etc. from club members to move them into position. We even "rolled" one across a field and thru some woods using fence posts as rollers under the rails.

 

[Lippyp]

You could build a ramp either side and cross Dukes of Hazzard style.............

 

[buening]

Would you drive an ATV across a rope/cable type bridge? I know I wouldn't

 

[Smilodon]

Would you drive an ATV across a rope/cable type bridge? I know I wouldn't

Sorry, not to take things too off topic, but everytime somebody says "bridge crossing" I think of this...

I have to put in a plug here for a great "adventure motorcycling" DVD... "One Crazy Ride". I was lucky enough to see it in a group setting with some of the "cast" in attendance.

What does it have to do with this? If you look at the last 40 or so seconds of the trailer (it's about five minutes long), you will see the beginning of a (Royal Enfield!) bridge crossing that will make your hair stand on end!

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[Mike83]

*best to build a bridge too strong than weak*
[/LIST]

chris<pixelmonkey>

Profound statement there.

In any case, you have a long span to deal with. I like the culvert pipe idea (Texas bridge), but you will probably have trouble doing anything that affects the waterway (anything in the water will cause a "backwater increase" which if large enough (we're talking fractions of an inch here) will affect everything upstream from you.) Flood insurance will change, etc. Believe me, we do hydraulic analyses to determine this stuff and we know the implications.

A bridge the size you need is a little out of the homebrew realm.