Any ideas on how to build a bridge?

[lear]

I have a stream on my property that I need to bridge. The bridge needs to be able to support a tractor (Massey 135) and 7ft flail mower going across it. The Massey is approx. 1.5 metric tonnes and the maximum lift is 1 tonne so it needs to support say 2.75 to 3 tonnes. The stream is 2 metres across and then approximately 1 metre on both banks to hit firm ground.

If you look at US forums for tractor folk they seem to knock bridges up over creeks with Billie-Bob and his backhoe in a weekend - and then show a huge 10 ton skid-steer with full logging gear parked in the middle of it. Over here it seems to require resurrecting Brunel - and enormous cost!

Obviously I’d rather not fall in to the stream...but it doesn’t need to take tanks (actually that’s a thought) and will only be used say once a month. It is also so far down my wife’s list of priorities that it will probably need to built secretly in the dark.

Surely it can’t be that difficult...can it? Any ideas or suggestions on material specs or anyone done anything similar?

[lear]

Thank you very much for all the suggestions! Steel I/W beams and sleepers is what I had in mind. Hadn’t thought of block and beam. Though from the tables I very briefly looked at, would the blocks support the sort of point load I’d be exerting driving across them?

Re permissions it’s a good point and we’ve made provisional enquiries with the LA. It’s definitely not considered a main watercourse and is very low flood risk (it’s very rural) but we’re waiting for them to confirm what we need to do.

For the I beams my main worry is how to stop them twisting - I’m no engineer (as is no doubt very apparent!) but tractors are quite bouncy with the agricultural tyres and kit on the back. So I guess the beams need to be well webbed together internally with a top covering bolted on to the flanges.

Will post pics of the crossing point...last attempt was embarrassingly unsuccessful when the bank collapsed...

[lear]

Manners2001 said:

I'd go with steel screw piles rather than concrete pads footings, with a steel 'I' beam ladder structure infilled with either suitably sized steel reinforced concrete lintels or suitably treated and sized timber.

The screw piles will avoid excavation and having to install mass fill concrete (we use them railway lineside or at the side of roads - great kit). They are designed so they come with an appropriate plate for a bolted connection to the steels...

Thanks for that - really interesting suggestion. I think the bit I’m going to have most trouble with is dumping a load of concrete in the ground rather than flood risk. It’s in designated ancient woodland so Natual England won’t want me poisoning the lichen. Steel screws could be the answer!

[lear]

Munter said:

I of course then had to do that, despite not needing a bridge. Weird and wonderful stuff there.

For the OP:
http://www.bridgesforsale.co.uk/bridge-for-sale/9m...

That looks great! I’ve seen various posts on US tractor sites suggest getting hold of an old plant trailer, taking the axles off and just dropping it across the gap!

[lear]

So, those rare occasions when one is pleasantly surprised by how helpful the authorities can be...The chap in charge of such matters for the district council just called back and said as it’s not a major waterway that no consents are required from them and we have no requirement to notify as we’re not affecting the stream bed (I didn’t mention dropping a Range Rover in it). It’s outside of the environment agency’s remit. Not only that he also happily gave me the details for their private contractor who built a very nice footbridge further upstream for the council - and who used to be head of bridges for E.Sussex county council.

Hmm, so no real excuses not to get building now!

[lear]

Wow Steve, that sounds like some serious bridge building! I fear my intended effort will pale in comparison! What is structured steel sheet?

I still like the idea of a truck bed - was thinking a bale trailer would be ideal as they're a bit shorter and have less road gear attached to them. However I'm leaning towards steel I beams on screw piles with sleepers as I do want something permanent and reasonably aesthetic.

I just saw the most amazing suggestion on another site (which I am not proposing!!):

"Somebody round here rolled round bales into dried up stream
Bit of cheap shuttering
Then ready mix concrete
Instant bridge with arch
Cut bale up with chainsaw"

Culvert a good option but will definitely need consent and I think the water will occasionally get too high in flood season. Will post some pics of the intended site later today...

[lear]

marky1 said:

Try these guys?

http://www.beaverbridges.co.uk/

Thanks - actually got an email in to them asking if they have any of the short span bridges they rent available to buy.

[lear]

Sorry for lack of update; going to be a slow build this! Taken three days to come to terms with the fact my bridge will be pathetic compared to Steve's magnificent engineering. Though I think mine needs to take a bit less traffic as well as being built so my wife doesn't find out. So have been looking into screw piles as suggested earlier. Having spoken to a couple of installers, they seem to be the perfect solution for the footings. Though the one quote I've had so far is for £5k for 5 screws which seems a lot doesn't it?! Not sure what comparable concrete pilings would work out at but vastly prefer not dropping a load of concrete into the ground given the siting. However there are a couple of places you can buy the screws and rent the low speed/high torque driver - either hand held or to attach to an excavator. Can easily get excavator on site so looking at that route... A few pictures of the site:

Firstly, my Massey which needs to cross the bridge as everyone loves an old tractor right?


This is the stream. Which is very gentle in summer:



But is a bit bigger when the rain comes:



This is where the bridgehead (like saying that) will be as it's narrow at about 1.9m across with firm ground on each bank



And this is what awaits the other side...mowing!

[lear]

Im seriously impressed you managed to have all that work done for less than 5k! I had thought about the pad route - and indeed creating a ford. The problem is that the ground on both sides of the stream gets seriously wet and unstable with rain - its basically a small valley on heavy clay with numerous springs running into it. So I think anything on the surface will just sink over time. Similarly with a ford there is just no where you could get the grip going in and driving out - those tractor tyres become big roller skate wheels once they fill with clay...

Though it has given me a thought; I wonder if I could sink telegraph poles as piles in combination with the compacted crushed stone? The guys I use have a big auger that would be perfect and can go deep - they used it to put up my pole barn.

[lear]

Hope nobody minds a bit of a thread resurrection? Just as I was about to start bridge building this time last year, we ran into a planning permission issue with our house. Resolving it dictated whether or not we wished to stay or sell and so we put further works on hold. Over a year and much banging of heads against walls later, planning permission is finally in...which means I get to start building my bridge! Groundworks chaps kicked off yesterday:
So, this is where it is crossing


First step, pulling that tree and a few others (not actually sure how they got the excavator to the other side):



And preparing the ground both sides:




And a pile of nice heavy reclaimed sleepers ready for the deck:



More to follow as we progress!

Edited by lear on Tuesday 16th July 21:59

[lear]

Andeh1 - and I'm pleased to say we're pretty much going with your proposed solution from the second post. Two big RSJ's, sleepers sandwiched in between and bolted to the webs with titanium bolts. Ends of the bridge bolted to concrete piles that will themselves be tied together with the piles going into plastic pipe to minimise leaching. Or something like that...

[lear]

Good progress today (by everyone but me!)...

First had to cut / extend the level access down to the stream and meadow:



To enable this to get the materials down without falling over:


Then the piles drilled and sunk in heavy piping:


And a reinforced ‘bridge’ poured between the piles onto which the steels will be bolted:


To be repeated on the other bank:


So far so good; though it did strike me I could probably have just chucked a bunch of sleepers over the gap, strapped them together and driven across...but hey-ho let’s build a bridge instead!

Edited by lear on Friday 19th July 22:48

[lear]

That’s a lot of concrete for the foundations! Looks a bit bigger than my effort - be interesting to see what’s going on top.

[lear]

Actually you've just reminded me of something I hit upon when looking at this a year ago...my first name is actually "Kai"....I think I need to get a sign made up!!

[lear]

Piles and pad on the other bank went in today....

[lear]

The steels arrived today...:



And some footings built up to level off to the opposite bank...:



Starting to feel this is a lot of building to cross a not quite 2 metre gap. Culvert, couple of boards across, old trailer or digging a ford might have been simpler!

[lear]

Have had a bit of a bridge building hiatus given the weather. Not exactly Whaley Bridge but heavy rain and heavy clay meant the excavator couldn’t slither across. Restarted today and finally we have something traversing it in vaguely the right direction:




And an exciting pic of a load of hard core to build up the approaches...(I am getting that slightly sledgehammer-to-crack-a-nut feeling again)...:

[lear]

biggiles said:

Great seeing how the bridge(s) are progressing. How much load do you think it will be able to carry? An ag trailer can be >10 tonnes across a few closely-packed wheels.

Oh it won’t be anything like that - its primarily for a Massey 135 plus big flail mower and that sort of thing - 2 tonnes tops. Possibly an excavator as have decided I need/want one! It’s been ‘designed’ to take 3 tonnes though that’s possibly stretching the definition a bit...

[lear]

At long last I can now declare us bridged! Pretty much finished today except for some logging and tidying up.

The approach:


The view from any passing ships:


The deck:


The inaugural crossing:


Nobody died...:


Thanks for all the advice on the way through!

[lear]

AlmostUseful said:

Well where's the fun in that? I was looking forward to "Help, how do a I get a crane down here to rescue my Massey"

That’s where this whole malarkey all started! I tried to drive the Massey across a few months ago...with the predictable result below when the bank collapsed. It ended up buried in clay to well above the axle sitting in the stream for two weeks. Had to ask the same chaps to lift it out with the excavator...at which point they suggested it might be time for me to let them build that bridge we’d been talking about...