small bridge .. anybody done it?

[rockriver]

there is small creek that we need to bridge near us...
I can do a foot bridge with no concern...
but
would like to be able to drive a small piece of equipment over it.
maybe 4000 pounds.. 6000 would be nice.

I can shorten span... but 10-12 feet is first choice.

has anyone done or have an easy source for what is necessary support wise...
6 foot width minimum... will probably go 7ft.
one concern is water flow... half of year dry or very little water flow... several times of year it will get out of banks...
4 foot deep.
'
any comments, references would be helpful.!?.
purposes... minimum -- level is enough support for my skinny self and a 1200 pound mower or a golf cart or a 4 wheeler next level is a compact tractor...

rr

[protus]

When dry...level....grade with rock...add snorkel kit to tractor truck...car and go fir it :).

That much weight you'll want some body with structural knowledge past what I got. Though I see concrete ....and lots of hardware involved :)

[rockriver]

I attended a little fellowship of fellows last evening...
so I posed the above question..
a new friend... quickly explained how to bolt 2x10's together and proceeded from there.
an old friend ... then picked up the discussion with the benefits of using a power/telephone pole.
another old friend... picked up the story with the benefits of an I beam or H beam made of steel.

a third ole friend... goes... "rr, I think you need my backhoe"

[610Alpha]

Not sure if you can do this or not...it depends on how the people at the "department of making you sad" are.

My thought would be to look into a 2-3 metal culverts and a bunch of dirt/rock above them might work. Not sure if it would be more cost effective vs a bridge but its an option I think who knows I could be wrong. I haven't done this but see people use metal culverts all the time to get across ditches.

http://www.metalculverts.com/technical-info_handlingweightscms.htm

[rockriver]

alpha,
I think you are on the right track... especially practically speaking..
last year my driveway culvert collapsed (2 24" pipes) old metal..

I was fortunate (blessed!) and located a 48" plastic road quality culvert that had a small defect...
road dept didn't want to use it and I got it for great deal...

if I could find another deal that would be great. and quick.
I did want to "build" one this time... and will unless I stumble on another deal for a metal or plastic culvert...
build, as in, measure, cut, nail, screw!!
if I go with a metal culvert or plastic, I will need 48" or more. and during a few times each year, 48" isn't big enough!

[Lowdown3]

If you use multiple culverts be sure to anchor them well and put full bags of concrete on the approaches and in between as the water runs in.

The bags of quickcrete might run you $3.50 each, but I've never had a culvert wash out after using them as a brace for them.

[610Alpha]

if I go with a metal culvert or plastic, I will need 48" or more. and during a few times each year, 48" isn't big enough!

I was thinking of multiple culverts since your op said "10-12 feet", you could do 3 - 48" or 2 - 72"

I have never installed a culvert so do not rely on anything i say.

[alco141]

the most critical part of building a bridge are the piers you build on each side these need to be strong with rock and concrete, you could just buy an old flat bed trailer and take off the wheels and place it from pier to pier over the creek after you build the piers. the culverts will cost a lot less than building the bridge even using my trailer method. my understanding is that anchoring the up and down stream ends of the culverts are critical, if water gets under the upstream edge it will take out the whole structure, so concrete of the ends is important. some information about installing culverts over streams:

http://www.na.fs.fed.us/spfo/pubs/stewardship/accessroads/stream.htm

http://www.motherearthnews.com/diy/culvert-installation-all-you-need-to-know.aspx?PageId=3#axzz345Fjalwr

alex



alex

[flightorfight]

Only problem with using culverts is if you have debris wash up and create a dam. The pressure can push the culverts out I found out from experience.

[cpt_sfc]

This is something I can help with 14 years as a combat eng. officer. The best way to get all the info is get a combat eng. officer handbook, they should be around or maybe on line. Mine is 20 years old but tells you what kind of timber , spacing, how strong types of wood are, the whole ball of wax. Handbook is about 2 inchs thick and packed full of very useful info. A army surplus store might have one or amazon. If you know anyone at ft. Leonard Wood that is the new home of the army ENG. I would post a PDF or send a copy but I am a computer idiot. If you have a saw mill or Amish near you they can cut the timbers for you. Culverts are a good idea also except the flooding. All depends on stream type , flow etc. Good luck let me know how I can help.

[cpt_sfc]

PDF FM-5-34 new 2014 I think this is what your looking for big download. US Army Manual pdf format. Also look under military engineer manual Enlisted/officer. Mine is circa 1987 gotta older one somewhere.

[eeyore]

Might want to talk to someone about the 100 year flood plane does in that area. I know the place I lease in WVA lost a state constructed bridge (concrete and steel) and part of the roadway when back to back 100 year floods happened.

I'm a little out of my league with this one, but if you wanted to try to do something temporary only for a few years, use rough cut lumber as described and pour a concrete post in the center if you had too. The engineer book seems like the place to get that sort of information.

[cpt_sfc]

If this is not a controlled (by .GOV stream) you could even build a floating bridge that rises and lowers with the water. It is also in the FM. Only diff is what to use for floats and the on ramps and you have to cable it off. A friend of mine used an old pontoon boat stripped down to the frame He drives a tractor over it and it sits in a huge ditch for crops. Most of the farmers use pre stressed concrete spans that are dug into the banks on either side. I think all that is in the FM.

[alco141]

get a 40 foot flat bed trailer and use as bridge deck, build up either end with concrete and rock to ramp up to the bridge.

[EX121]

My 2 cents, is really consider the approach ways. I've seen a few Farmer built bridges become useless when the approach ways washed out in a flood.
A friend built one out of an old railroad flatcar. He set it on rock & concrete piers.