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Discussion Starter · #1 ·
Spent my vacation last week working on a bridge over the creek. I've built the two main supports and have one in position. The span is 32 ft the support you see is made of triple 2x12 , the diagonals are 2x8. There will be another of those
5 ft away from the first with a triple 2x12 also down the center. The top will be
2x6s. I figured each of the main supports weigh approx 800 lbs. So my question
is any idea how to figure the load capacity?The biggest thing crossing this will be either a golf cart or our lawn tractor.

Later
Rich
 

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Discussion Starter · #3 ·
It's made from that AC2 treated stuff, though I'll probably smear something on
it for protection.One of my neighbors swears by ATF fluid.Still thinking about
some metal to the the top junction. When I get it nailed together this weekend
I was going to string it and see how much it deflects with drunken MX bikers
standing in the middle.Wonder if there will be a difference before vs. after
they recycle their beer.

Later
Rich
 

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(oYo)
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It looks like your main beams only extend 12-18 inches over the top of the slope. Is that accurate?

I'd have probably elected to go a good 48" inland to avoid any problems with errosion in the future.

Did you price Steel I-Beams before choosing the 2X12s? I don't know that they would have made a better choice but I certainly would have pondered them as an option.

This looks like a really fun project, keep posting your progress when you get a chance.

I'm just about to start finishing my basement and i'm contemplating whether or not to subject you guys to another photo thread...
 

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Discussion Starter · #6 ·
They lay on top of notched 6x6s which go down about 3 1/2 feet into the ground. Steel would have been a bit more money plus I don't think I could have moved them with out heavy equipment. Also I don't think my lite-jet torch
would have been up to the job. Damm now that I think of it I could have tried to convince my SO that I just have to have that TIG unit.

Later
Rich
 

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Discussion Starter · #8 ·
Here's a shot of the 6x6s, the triple 2x12 slip over and sit on the notches.
The blocks around the 6x6s are temporary ,when I get the pieces all in place I'll fill the post holes with cement.

Later
Rich
 

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Isn't That Somethin'
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seal it with oil. around here oil is pretty prevalent so all the old timers used straight crude. now i know straight crude is hard to get a hold of but using a thick HEAVY weight oil will do the same. it waterproofs it and bugs don't like it and believe it or not it's still cheaper than commercially available sealers. looks like a couple of 5 gallon pails should do it for you plus it's good insurance and lasts for a long time. a good thick coat or 2 initially should be good for 10yrs or more then just follow it up with a coat every so often.
 

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The "Eagle" Has Landed
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I am no engineer here, but I am curious. Do the diagonal and vertical beams play a part in the construction. They they help with load bearing or anything? I am just wondering why not just a straight bridge across. I did not see the diagonal beams protrude below the bridge itself - like into the embankments. :confused1:
 

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Discussion Starter · #15 ·
That's the plan, I was going to slap another vertical 2x12 so it's a good 1 1/2ft
higher that it would be now. If I did it now anyone standing on the pegs would
be taken to the ground.

Later
Rich
 

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Discussion Starter · #19 ·
Engineer?? There's a guy down the road with stripped overalls and an oil can he carries around with him.He said it looks good.Next week I was going to run a string from one end to the other get about 1000lbs on it and check how much it deflects.
I'm shocked as to how level it turned out.

Later
Rich
 

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(oYo)
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Okay... thanks. The bridge looks great. Craftsmanship looks spot on, obviously well thought out. Bravo.
Sure, picture a heavy load at the center point of the crossing. SOME load should be delivered up the vertical to the intersetion of the 2 diagonals and distributed out towards the ends of the structure...

Did you model this out of balsa first? :laughing4-giggles:

I love it.
 
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