Wooden bridge span question

[cdhd2001]

I built a similar bridge spanning 12 ft, with an unsprung distance of 10 ft. Building for ATV's is easy, horses are a diferent story because of concentrated heavy loads as they trod across. I used 3 2X10's bolted together to make one joist, used 3 joists, and decked it with 2X8's. Have driven a diesel F350 over it and a 1000lb horse with a fat guy in the saddle and worked fine!

This sounds exactly like what I need to build for my little creek. How wide and what kind of footings did you use?

 

[Aquaman]

I want to build a wooden bridge across a creek for people, ATV's and horses.

Is 16' too much?

I built a 16' free-span bridge for exactly the same uses as you out of 2x12's and as you can see, it will even hold up a weiner dog!! The trick is to run your treads lengthways instead of across the joists. This spreads the weight of a hoof, foot, tire, etc. out along a larger area. I made it 4 boards wide, each 2x12 being about 11.5 inches wide for a total of 46". I deliberately made it this size (narrow) to keep unwanted vehicles from having access to my trails. I used 5 2x12's for the joists, with a 2x4 on each of the 3 middle ones. This keeps you from having to place the treads where they are "sharing" a joist to fasten to. I hope the underneath picture shows this clearly. Also, GLUE and SCREW everywhere 2 boards come together. Nails have no place in a project like this. The hand rail is just a truss in disguise to add support in the center making the true span only 8'. Putting the bridge above ground and back-filling up to it will add many years to it's life. There's plenty enough time for it to settle on it's own. Where I live, 16'x2x12 CCA boards are about $25 each. Do the math. Let me know if you need a better pic or whatever.
Randy

 

[Coyote]

This sounds exactly like what I need to build for my little creek. How wide and what kind of footings did you use?

Standard 8 ft lumber, the bridge is 8 ft wide, 12 ft long. My footings were dug into the banks and set on 2" flat cinder blocks, I didn't pour anything. I am spanning over a "dry" creek bed. It is really a draw that carries water only after a heavy rain. Here is an early picture, there is no center joist yet.

 

[dillo99]

I built one that is 16 feet long and 5 feet wide - I drive my tractor over it which weighs close to 3000 lbs. when the backhoe is attached. It has four joists - 2x12x16. Planking is 2x10s.

Works great - no problems at all.

 

[RobA]

I built one that is 16 feet long and 5 feet wide - I drive my tractor over it which weighs close to 3000 lbs. when the backhoe is attached. It has four joists - 2x12x16. Planking is 2x10s.

Works great - no problems at all.

Any pictures?

 

[dillo99]

Don't have any handy but I'll try to get out there this weekend and get some to post.

 

[katyhorn]

Wayne, it has been a while, but can you provide details on how you did the splicing? I am an engineer (chemical) but don't have the practical experience to do this.