Any ideas on how to build a bridge?
Discussion
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?
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?
Andehh said:
What an awsome project to have!!
I would look at RSJs with sleepers tucked/sandwiched between, then resin-bolted/buried into concrete either side?
Seems a fair place to start.
This, just open the span tables and see where your load-case leads you. Or ask the supplier to work out what you want, lots will do that for you. I would bolt two RSJs together using some smaller beams to tie it all together, but sleepers or block and beam flooring will be a good option for filling in the gaps. And leave gaps between the sleepers/beams, so they last longer, you use fewer and rain/mud etc washes into the stream.I would look at RSJs with sleepers tucked/sandwiched between, then resin-bolted/buried into concrete either side?
Seems a fair place to start.
If it's on your property, does it need any authority approval or is it entirely up to you?
If (I hope) the latter, then first play bridge builder (available on all platforms) then consider what sort of visual you're looking for. If you don't want "sides" then you'll likely want a pair of steels for the span, and sleepers inset into them. However, if you could get a number of decent lengths of timber, pressure treated, you could build something very simple and effective this way. Timber can take surprisingly high loads.
Great fun project. Take pictures.
If (I hope) the latter, then first play bridge builder (available on all platforms) then consider what sort of visual you're looking for. If you don't want "sides" then you'll likely want a pair of steels for the span, and sleepers inset into them. However, if you could get a number of decent lengths of timber, pressure treated, you could build something very simple and effective this way. Timber can take surprisingly high loads.
Great fun project. Take pictures.
Watchman said:
If it's on your property, does it need any authority approval or is it entirely up to you?
As above: very much the former, if it's regarded as a main watercourse. Given the issues around flooding in recent years, they will be particularly concerned that whatever you do doesn't potentially obstruct or restrict the flow of the stream in flood.
How about using old lighting truss as the support?
https://secondhand-sound-and-lighting-equipment.co...
https://www.ebay.co.uk/sch/i.html?_sop=12&_fro...
You need the heavyweight quad stuff but four lengths of this strapped together should take the load. You'll ned a top surface as well of course but as it's the truss is open it won't restrict the flow of water as much should it rise that high.
https://secondhand-sound-and-lighting-equipment.co...
https://www.ebay.co.uk/sch/i.html?_sop=12&_fro...
You need the heavyweight quad stuff but four lengths of this strapped together should take the load. You'll ned a top surface as well of course but as it's the truss is open it won't restrict the flow of water as much should it rise that high.
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. A few companies out there do them (Google and Youtube are your friend here), but for the sort of loads you are talking about they should be able to install with handheld kit rather than an adapted excavator.
The screw pile installer may even be able to spec the steelwork for you, if not a local Engineer should be able to do it in a couple of hours including detailing the connections. Once the piles are in the rest you can do yourself assuming you have enough muscle/suitable kit to move the larger steels.
I've got a similar project going on in the woods we have just bought, although ours is bridging a ditch only for pedestrian traffic so slightly disappointing in scale in comparison to yours.....
Good luck!
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. A few companies out there do them (Google and Youtube are your friend here), but for the sort of loads you are talking about they should be able to install with handheld kit rather than an adapted excavator.
The screw pile installer may even be able to spec the steelwork for you, if not a local Engineer should be able to do it in a couple of hours including detailing the connections. Once the piles are in the rest you can do yourself assuming you have enough muscle/suitable kit to move the larger steels.
I've got a similar project going on in the woods we have just bought, although ours is bridging a ditch only for pedestrian traffic so slightly disappointing in scale in comparison to yours.....
Good luck!
FourWheelDrift said:
Have you googled "used bridges for sale UK" ? To get a feeling for cost.
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...
Munter said:
FourWheelDrift said:
Have you googled "used bridges for sale UK" ? To get a feeling for cost.
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...
- http://www.russianmilitary.co.uk/details.php?id=20...Hopefully, with the recent rains, you have some idea what the stream can look like in flood conditions? This could an important factor.
Using box culverts is another potential solution (in pairs, if necessary)
https://www.eliteprecast.co.uk/service-protection/...
The carry normal Highway loading. Arrive on Hiab and dropped insitu.
Using box culverts is another potential solution (in pairs, if necessary)
https://www.eliteprecast.co.uk/service-protection/...
The carry normal Highway loading. Arrive on Hiab and dropped insitu.
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...
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...
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