replacing a farm bridge 15~16' span

[skyking1]

They removed the rotted stuff and want to put it back It was sitting on a row of half RR ties hand dug in as pilings on a cap, and (5) 6x12 x 16' notched at the ends a bit to sit over the cap. All pinned together.

My plan is to use some magnum blocks @ 15' apart as I can set those with the mini. I have a whole stack of new looking 6x12x10' deck boards to put on.
I am going to look at some switch ties, but they are used and I would be concerned that they may sag over time. I found some real treated bridge timbers 10x18, but they are a drive and some extra $$
I think those would work with just two at 6' OC.

Planned use is a pickup truck, possibly a light trailer but the span is so short it is one at a time on it.

 

[skyking1]

I found some 6x17 x 20' used treated beams for $100 each, they look to be used dock beams. I can go through the pile and come up with 4 good ones at that price, and freshen up the ends to get rid of the big pin fractures and cracks.
If I build it with a 36" center gap and 18" between the paired side sets, the beams will be 8' wide across the top.
I can use the fresh cutoffs for blocking. It will be stout beyond any practical use.

Those are 6x18 beams pictured here across the pile caps. 4x12 deck boards, and I think that dock was rated for 150 PSF and pretty large forklifts and trucks.

 

[Delmer]

I'd think either way would be fine. That's a crazy good price for the beams, must be the city vs rural. RR ties would be fine too for the expected load.

 

[skyking1]

Yes I am pumped about those beams. I like the redundant setup with two per side. I will see if the guy will proof load them for me after I pick out 4. We can set them on blocking and then rest the loader on it midspan and lift up the tires. It would weed out a fractured one that I could not see.

When I asked about the switch ties, they were $5.50 a foot so more money than those 6x17 and WAY less strength. The only advantage was a slightly shorter stack up. I can deal with the deck being 4~6" higher with just a dab of gravel.

I suggested we start looking for lumber and metal roof to make it a covered bridge

 

[DMiller]

Just remember to add cross blocking between the beams so they do not can not roll out.

 

[skyking1]

another concern is high water floating it off the foundation. The last bunch of wood was pinned together but not otherwise anchored to anything.
My plan is to set these magnum blocks on gravel keyed into stream bed, then put cross rebar and some verts between the two layers.
Pour that in and then wiggle in J-bolts.
I have 6" angle iron and I will make corner hold downs. torch holes on the angle iron and lag bolts in the sides of the beams, and J-bolted to the footing.
The cutoffs will make handy blocking. Block between everything and then pin it all together with the 6x12 decking at that blocking. Drill it and drive in concrete form stakes.

a couple of pieces of plywood on the ends to close up the "forms"

I don't know how the look of a structure would be there in her yard, but I think an open sided cover made with recovered barn boards would be lovely and double as an outdoor deck over the creek. This little job reminds me of how much I would like my own water.

 

[skyking1]

I have the blocks, gravel, the machine is there. I decided to hammer some spalls into the creek bottom and top with crushed and hoe pack it to grade.
I can get 2x4 or 4x8.
Decisions decisions.

 

[skyking1]

I got plenty of 4x8 spalls and we had a great day, even after finding the 1" poly pipe coming from the spring on the hill.
I kept working on the spalls while he fixed the line and we got the rest of the demo done today and the block is set and ready for rebar and concrete.

That propane tank is full and sitting too close to a rotting RR tie wall. The solution was to place a couple of blocks below that wall. I will tear off the last couple of ties when I rock it all in.
I reached the block as far as I could so I would not have to haul them around.




There is rubble all along the bank and I removed a minimal amount and tucked the abutment blocks in place.



Other than not balancing well, the blocks are easy to work with. They set the picking eyes at the physical center but they are quite face-heavy, as the blocks are angled for making round walls.


he'll set bar in that trough and pour the concrete and set J-bolts. I will pick out 4 good beams and see if the forklift operator will proof load them for us.
The clear span is under 13' so this will support quite a bit more than it will ever see.

 

[skyking1]

I'm already cooking up a really nice roof for the bridge.

 

[cuttin edge]

So it's kinda functional, and nice to look at. When I started reading, I was going to suggest an old flat bed trailer. The snowmobile and atv clubs here use them. Cut off the axles and set them in place. Lots of old logging trailers around her that are no longer used. But I think what you are making will look pretty neat.

 

[CM1995]

So it's kinda functional, and nice to look at. When I started reading, I was going to suggest an old flat bed trailer. The snowmobile and atv clubs here use them. Cut off the axles and set them in place. Lots of old logging trailers around her that are no longer used. But I think what you are making will look pretty neat.

CE that's what I thought at first as well - an old flatbed trailer.

Sky - How much are those blocks a piece?

 

[skyking1]

The flatbed trailer would exceed the mini's ability to set it, but that is not why we did not go that way.
We already have a huge stack, I mean 3x what we need of the 6x17 x 10' long deck boards. They are just short beams. We are adding anchors in the center and we will split a deck beam over that, so we can stick out 2' on each side to set the shear wall of a roof structure on each side and no impinge on the width of the bridge. I'll sketch up the roof design.
The 4 long beams are only $400 and I can easily set those with the mini.

The blocks were $151 each my price, retail was $182. They did the trick.
He sent me this, but they are already poured now.