Bridge Ideas for multiple creek crossings

[WinterDeere]

Sportsman beat me to it, but I'd be using large culvert pipe for all or most of your 3 - 5 ft. crossings. Easy, quick, strong, and long-lasting... almost everything any bridge is not.

If you use concrete culvert pipe, it's commonly available up to 108" (9 feet) diameter. I think plastic corrugated usually stops around 72" (6 feet) diameter.

<-- has bridges in need of replacement

 

[2manyrocks]

The true bridge planks I remember were not 2x (actual 1.5 inch) pt from the box store but something more like actually 3 inch or more thick oak. They were spiked to the tree trunks used as beams with some very large nails.

WinterDeere is likely right that culverts would be less expensive and longer lasting than trying to span a short distance with a bridge.

 

[bcp]

Mobile home frames are very flimsy without the structure of the building on them.

Bruce

 

[Gordon Gould]

Have you seen the simple design used for skidder bridges. These are for 30,000 lb loads so can be scaled down for your use. They are 4' panels for mobility. I plan on making one using this concept 8' wide using 6x6's spaced with 2x4's.

 

[deezler]

I would do 4, here is 3.


Masonry is ideal at each end.
View attachment 1938130

Hey I recognize that footing! Such a fun project.

I pretty much just used what I had around, spare CMU blocks, 3 course high on each side. Has held up very well so far.

I only had 3 telephone poles, really wish I had 4 or 5 underneath my decking. But thankfully my decking is double-layered, old-school treated 2x6s that should last a nice long time.

 

[EddieWalker]

Bridges want to fail. It's just a matter of when that happens. The more wood that you use in your bridge, the sooner something will fail. If you are dead set on building a bridge, the next question you need to ask is how long do you plan on using it? Are you young and expect to use this bridge 50 years from now? Are you retired with a decade or so of time left that you'll be needing it?

From what you have said in your original post, it does not sound like you have a lot of experience in framing. Your choices of materials listed to build the bridge are not what I would use. Even more important then what you use to build the bridge is what you use to support it. That needs to be the first question.

Culverts are simple, affordable, and if sized big enough, will last for a century. If they fail, it's easy enough to fix it and use it again.

Even easier is to just dump a lot of large rock in the bottom of the crossing.

 

[2manyrocks]

Have you seen the simple design used for skidder bridges. These are for 30,000 lb loads so can be scaled down for your use. They are 4' panels for mobility. I plan on making one using this concept 8' wide using 6x6's spaced with 2x4's.

View attachment 1938150

What is the weight and how does it get moved?

 

[bdhsfz6]

How deep is the water and how swiftly does it flow?

Since the streams are dry part of the year, why not a shallow water crossing using crushed stone?

 

[Mallard1]

Thanks for all of the quick replies and good advice. rather than quote everyone I will do my best to answer the questions all at once.


The choice of materials was mostly based on what I have on hand right now, I have an endless supply of free 2-7/8 pipe, I can get oak boards for the decking done for just the cost of having them cut up as we loose oak trees every year.

4 of the 5 crossings are just 18" deep, 1 is about 3' deep. I would prefer a bridge to a low water rock crossing so I can cross at anytime.

The issue I have with culverts is we do a lot of controlled burns here so that would make me install galvanized culverts, also with all of these crossings being in timber areas pine straw, oak leaves and branches will clog the culverts like they do at all of the road crossings. after every hard rain I have to clean all of them out and with a bridge most of that will flow underneath.

at another property we have we have several bridges that are 4 telephone poles, two per side and then decked with shaker screen from a rock quarry and they have been holding up for 20+ years, however this is just for UTV traffic not truck or tractor traffic.

most of these crossings will look very similar to the youtube video posted by bmaverick except lots of trees all around.

I will try and get a few pictures this weekend of what I am looking at.

the stream is not very fast even during a hard rain, there is about 10' of elevation change over the course of 500 yds straight line distance but the creek winds the whole way so it moves slowly.

 

[bcp]

I was on a farm that bridged irrigation ditches with concrete slabs about 8 feet square, 4-6 inches thick. No idea what was inside the slab. Ditches were 4-5 feet wide.

Bruce