Building a bridge across creek

[pinetag]

Just wanted to share the process I used to build my bridge in hopes that it might help some of you looking to do something similar.

Disclaimer: I am not an engineer and take no responsibility for anything that is built in a similar fashion to anything I'm providing here.

The supplies I used...
1. Treated 4x4's for the footer posts
2. Treated 2x12 (16') boards to create the main support beams and joists
3. Treated 2x4's for lateral cross bracing
4. Treated 2x6's (12' cut in 1/2) for the deck boards
5. Treated 2x10's for the runners on top of the decking
6. Deck screws
7. 1/2" bolts - various lengths but 6" was used for the beams and 10" to connect to the footers
8. Gravel and concrete

Here is what I was working with. A spring fed creek that has flowing water year round and is about 17 feet across (total span is 21'). The water level is typically 12" deep but I've seen it as high as 3' after a few heavy rains.

 

[pinetag]

First steps was to dig out my footers. I used some gravel for draining but I did end up adding concrete around these posts as well.

 

[pinetag]

Next step was to build the bridge beams. To get the full 21' span I was trying to achieve, I had to cut a couple of the 16' 2x12" boards down to 5' sections and then alternate them and bolt together.

 

[pinetag]

Then I added joists using joist hangers as well as cross bracing for lateral (side to side) suppoort. I started with just cross bracing on the bottom but I had extra boards so I put some on the top as well which gave me more to tie into for the decking boards later.

 

[pinetag]

I added some additional sections of board to create a sort of sandwich around the seams for the main beams. Two seams were toward the inside and two were toward the outside but unfortunately I didn't get a pic of the ones that were on the outside.

 

[pinetag]

I used a triangle bolt pattern to help disperse the stress at the seams.

 

[pinetag]

I started adding deck boards but I left the ends open in order to build up the dirt ramp to make a smooth transition from the ground onto the ramp.

 

[pinetag]

Finished up the deck boards and then I added some runners to help disperse the weight better as well as some guard rails for good measure. I used decking screws to attach the deck boards to the main beams.

 

[pinetag]

It will support the weight of the 4 wheeler with ease and there is no give or movement. I will be testing my dad's compact Kubota tractor in the near future.

 

[pinetag]

Start to finish...

 

[j-bird]

What sort of ballpark cost figure you have wrapped up in materials? Nice looking bridge......not so sure I would have the stones to try a tractor....... Curious to see how that goes for you......

 

[pinetag]

I was estimating about $500 initially but of course I ended up having to buy more of some things like bolts and concrete. I would say between $600-650. His tractor is a compact Kubota and only weighs 1500 lbs. We'll ease across the first time with me carefully watching from the side. LOL.

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[Doe Shooter]

Very nice work. Hope you don't get gully washers like we do around here.

 

[j-bird]

I was estimating about $500 initially but of course I ended up having to buy more of some things like bolts and concrete. I would say between $600-650. His tractor is a compact Kubota and only weighs 1500 lbs. We'll ease across the first time with me carefully watching from the side. LOL.

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I would push it across well before I would drive it across for the first time......I would suspect it will be fine....but you never know!

 

[buckdeer1]

I would put a couple cement blocks on the ground and wedge a couple 4x4 under there for extra support.I just pushed two electric poles across mine and built 2x8 on top to go across on.When i was trying to figure out how to get poles across a guy said just push them and it worked.I could actually just barely lift up on far end but pushed them right across.i would say they are 25ft

 

[pinetag]

I thought about the telephone pole idea but was unsure how I would even get them out there or down to the creek.

This weekend will be a "good" (or not so good) test to see how well the dirt around the ends holds up as well as how high the creek actually gets with heavy rains. We have been getting hammered and there is flooding everywhere. If the creek doesn't come out of its banks now then I should be good in all but the most extreme cases.

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[lakngolf]

Hope your bridge holds steady

 

[pinetag]

We'll see how it holds up after the rain subsides and current levels drop. Currently under about 1.5 - 2 feet of water...


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[buckdeer1]

I just drug them and had no issues,In fact a month after I built it a big flood cam through and I found it 100 yards away and drug it back and pushed it across creek

 

[pinetag]

Well it appears my craftsmanship held up but unfortunately I will need to re-position the bridge back into place. Probably will add a lot more concrete around the ends this time. The steel cable definitely did its job (second pic).

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