Trail Cameras Again

valis

Super Anarchist
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Friday Harbor, WA
If I'm doing that correctly, it says putting 2500 lbs in the middle will result in almost 3 feet of deflection. That's a little more than I had in mind.
Yes, if you put *all* the weight on one beam.  You have two beams so the load will be 1/2 of that, giving you a deflection (calculated) of 19 inches.  That's still probably way too much, and I don't know if the beam is being stressed beyond safe limits.  Now in reality with your long wheel-base you don't have a single-point load, so the deflection won't be as extreme. 

Steam's strut / stay suggestion may be a reasonable approach, but I'm not a mechanical engineer and wouldn't know how to accurately calculate the forces.

 

Pertinacious Tom

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Punta Gorda FL
Yes, if you put *all* the weight on one beam.  You have two beams so the load will be 1/2 of that, giving you a deflection (calculated) of 19 inches.  That's still probably way too much, and I don't know if the beam is being stressed beyond safe limits.  Now in reality with your long wheel-base you don't have a single-point load, so the deflection won't be as extreme. 

Steam's strut / stay suggestion may be a reasonable approach, but I'm not a mechanical engineer and wouldn't know how to accurately calculate the forces.
It'll be interesting to see how much it actually bends. My neighbor was over yesterday. He's a contractor and can build or fix anything. He looked at those beams and said, "That's what we make swamp buggies and equipment trailers from!"

I told him my general plan and he rejected it immediately as too complex and expensive. His idea was to sink a couple of piece of steel into concrete on both shores and then bolt the beams on. They're going to get stiffer because the next step will be to bolt long boards to the beams to use to screw on the deck. Big, rough cut 2 x 10's or something.

My reaction: "You're hired." Poor guy can't resist a project. He's building about a dozen homes right now, running his restaurant and nursery, and raising 3 teenage boys, so he has plenty of spare time for my games.

 

Pertinacious Tom

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Punta Gorda FL
How much for a pair of Breeding Pair of Koon Killers ??
That's a cypress tree. They're pretty smooth. Little f'ers can still climb up and down.

CoonClimbsDown.jpg


 

Pertinacious Tom

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How much for a pair of Breeding Pair of Koon Killers ??
Price went up! A family of them has figured out how to get into the chicken run and steal leftover food at night. I got some trail cam pics of them but they're not good. Just glowing eyes inside the coop.

But I do have a new picture. Bridge beams bolted to steel rails sitting in reinforced concrete piers in the ground. Waiting on the wood to deck it.

PondBridgeBeams.jpg


 

Pertinacious Tom

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Too late now, but did you think about putting a bit of camber in them?

 A nice sort of Monet-ish arch? (Not so dramatic, but.....)

I'm not even sure how/whether that could be done. I'm just using them as I found them.

A big pile of 16' rough cut 2 x 6's has appeared out there today. Might get it decked this weekend but I just had hernia surgery and am not allowed to do anything useful so that's my neighbor's boy and his buddy in the pic doing the work. They'll be back when they get back.

 

Mrleft8

Super Anarchist
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Suwanee River
I'm not even sure how/whether that could be done. I'm just using them as I found them.

A big pile of 16' rough cut 2 x 6's has appeared out there today. Might get it decked this weekend but I just had hernia surgery and am not allowed to do anything useful so that's my neighbor's boy and his buddy in the pic doing the work. They'll be back when they get back.
Cut a bunch of shallow "v"s in the beams, and weld the cuts up nicey nice.

But, yeah..... Next time.

 

Pertinacious Tom

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Cut a bunch of shallow "v"s in the beams, and weld the cuts up nicey nice.

But, yeah..... Next time.
It would look cool but I avoid cutting metal if possible and I don't weld.

It was too wet and full of cypress knees where one of the piers was supposed to land so the boys had to move it and drill a new 3/4" hole through the beam for that one on the left in the foreground of the pic. He asked me if that plan was OK and my only comment was when it comes to drilling big holes through big pieces of steel, better him than me.

 

valis

Super Anarchist
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Friday Harbor, WA
Bobcat at the bobcat-feeder (gopher holes) today in our NorCal yard.  We've seen this one (probably) at night on the security cams, but today I was able to use my good camera, looking through the bedroom window.

DSCN1298.jpg

 

Pertinacious Tom

Importunate Member
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Punta Gorda FL
Bobcat at the bobcat-feeder (gopher holes) today in our NorCal yard. 
Nice picture. I almost never see them in person or in daylight.

In this area, if someone says "gopher" they mean a gopher tortoise. We even have a day to celebrate them. They're a "keystone species" because lots of other critters use their burrows (and would be fucked without them).

There are already several pics in this thread of my dog carrying them around. She flips them over and guards them until I discover them. Two in the past two days because they're pretty active this time of year. Dogs can kill them but she doesn't harm them, just guards them.

 

valis

Super Anarchist
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610
Friday Harbor, WA
Cut a bunch of shallow "v"s in the beams, and weld the cuts up nicey nice.

But, yeah..... Next time.
Arches:  They work by converting bending force (beam deflection) to linear or compression force (pushing the ends apart as the beam tries to straighten).  You need to secure the ends, and for a shallow arch there is a lot of force pushing sideways.  I don't have the math chops to calculate the forces in an arch, but I could approximate using triangular geometry, as is done on a sailboat for the forces on turning blocks.

Anyway, you would need a significant arch to make a difference in your case.

 

BeSafe

Super Anarchist
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I'm not a Mech E. either but just eyeballing your setup and guessing at the load, it looks like the deflection should be around 6" max.

Pict.png

 
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