Idea for a Bridge deck?

[countrybumpkin]

Pics and size of your beams would help give us more to go on

 

[coldsteelva]

My neighbor and I share a bridge that is engineered by county regs to handle fire trucks. He and I are responsible for the upkeep. We just recently re-decked it with 4x6 PT lumber and it is secured with carriage bolts. The span is only half of what you're describing, but the same principle could be used. We have poured concrete abutments and steel I-beams for the span.

 

[rd_macgregor]

My neighbor and I share a bridge that is engineered by county regs to handle fire trucks. He and I are responsible for the upkeep. We just recently re-decked it with 4x6 PT lumber and it is secured with carriage bolts. The span is only half of what you're describing, but the same principle could be used. We have poured concrete abutments and steel I-beams for the span.

View attachment 551824View attachment 551825

Is that two or three steel I-beams? How wide is the deck?

 

[pmsmechanic]

Well what are you thinking? and whats the budget?

Basically I would look at how trailers are supported and decked. either wood or steel. Copy a HD trailer design for supports and webbing. Because thats basically what you are building....a trailer deck minus the axles and tongue.

Now there's a thought. You could probably buy an old trailer and redeck it for cheaper than building one. And then use it as a bridge!

 

[bcp]

I've seen several bridges made from flat bed semi-trailers.

Bruce

 

[Coyote machine]

My neighbor and I share a bridge that is engineered by county regs to handle fire trucks. He and I are responsible for the upkeep. We just recently re-decked it with 4x6 PT lumber and it is secured with carriage bolts. The span is only half of what you're describing, but the same principle could be used. We have poured concrete abutments and steel I-beams for the span.

View attachment 551824View attachment 551825

That's a really nice bridge and decking. I take it that it incorporates 3 main beams for support, and from the tread pattern, it seems the traffic spans between the two outer and one center beam, yes?

I built a similar style bridge across my pond spillway, with two used telco poles given to me by them when replaced with new. Since last year's storms I added a 3rd telco pole in the middle for extra support when I replaced some cracked/damaged pieces of 3" x 12" wide Hemlock rough cut planks. The decking is bolted to the poles with star drive round head large lag type thread bronze colored screws. I use it, on occasion to travel over with my tractor/hoe - probably 5K#s.

Maybe you, the OP, could get some specs from your local fire dept for a similar bridge span in your area for further ideas?

 

[coldsteelva]

Sorry, I'm late to reply. The decking is perpendicular to the beams. There are actually 7 I-beams there (fire apparatus isn't light). There are 3 in the tire patch area (to the inside of the side rail) on each side and then a single down the center for support of the decking.

The only thing that drives down the center of the bridge is my MF, the neighbor's Deere, and a Craftsman lawn tractor.

Where you see the carriage bolts, the bolts are actually bolted through a 2x6 that provides a wider bolting surface for the decking and is simply to prevent rolling/racking/shifting of the deck. Those 2x6s are wedged in tight against the underside of the 'ears' of the beams and between the abutments and are themselves bolted through the I-beams.

When there isn't so much water in the creek, I'll try and grab a picture from underneath. We were so tired, we didn't think to take any under there.

 

[buckeyefarmer]

When i worked on bridges like this yrs ago, we decked with PT 2x4 on edge, and nailed metal clips on each one that caught on the ibeam edge to hold it.

 

[PILOON]

When you do install a decking you only need a few fasteners to hold the deck in place.
That is if you add a side rail like 2 x 4's or similar to tie the planks together,'
The decking can then actually be 'pinned' to the steel beams with but a few pins here and there, simply to prevent 'slipping' about.
(Concrete contains stones that deflect nails but steel is consistant)
By 'pinned' I refer to using a ramset 'gun'.

 

[ovrszd]

The angle bracing in your second drawing, under the deck, is unnecessary. The bridge cannot fall toward either end because it will be pushing against land.