I am looking to span a stream about 1500mm with some prestressed concrete railway sleepers an wondered what load they would take. Car, transit or concrete truck. Is anybody up on structural engineering. I am using 300x300x1500 concrete blocks as abutments.
I'm not a structural engineer and I don't know much about concrete railway sleepers, but this sounds like an application they weren't designed for.
The "Structural Engineer's Pocket Book" says that a particular brand of pre-stressed concrete lintel (215mm wide by 140mm deep) can support a uniformly distributed load of 33.89kN across a 1500m span. That's for a custom-designed lintel supporting masonry, presumably a railway sleeper with the would be weaker, particularly when subjected to dynamic loads.
Here are some online beam calculators, but they are mostly for timber or steel:
You'd (At least) need to put them upside down, as they're designed to take two point loads (From the rail attachments) near the ends and distribute them evenly along the length. All the reinforcement is set up for that. I'd also be wary of using them in any critical application, as they're normally retired due to faults, some of which may not be apparent to a casual inspection.
You'd probably be better off in the long run using new wooden sleepers, or, preferably, a properly designed beam for the job.
railway sleepers an wondered what load they would take. Car, transit or co ncrete truck. Is anybody up on structural engineering. I am using 300x300x1
500 concrete blocks as abutments.Thanks MrWeld, but the links were over my head. I don't know what a udl of
33kn is in practice, (1/3tonne?) but it was the size of vehicle I was looki ng at and that would involve some live loading.9.8 newtons ~= 1kg force. So about 3 tonnes Uniformly Distributed Load.
Oh dear, so are these sleepers just concrete and nothing else, ie is there any metal inside it, perhaps tensioned at either end. Concrete is great under compression, but rubbish in bending or tension, The underside of these sleepers are going to be under tension.
sounds like you might need a lintel or a reinforced concrete beam. Brian
Yes, retired pre stressed ones tend to have a lot of rust in them which is why thy are no longer in use!
Brian
I say they wouild easily take it, yes...
lets face it, if you can run a truck over a skab of concrete with rebar in its base only about 4-5" thick you can for sure do it with sleepers...
In message , Richard Iansons writes
Might be worth asking in uk.railway, there are some industry pros in there.
Adrian
What sort of ground are those abutments resting on, and how was it prepared?
Above all, what are the penalties for failure? In other words, how deep is the stream?
With it only supported at 1500 mm centres?
In message , Richard Iansons writes
New sawn Oak *sleepers* are available.
railway sleepers an wondered what load they would take. Car, transit or co ncrete truck. Is anybody up on structural engineering. I am using 300x300x1
500 concrete blocks as abutments.The span is 1500 (as stated), the sleepers are prestressed (as stated)and 2
600 long, the foundation is rock. I am aware these are not as new. The smal lest section of concrete, as in most concrete sleepers, is in the centre at about 230 x 140 with 2x3x3 strands of probably 8mm but say 6mm wires at 40 mm c-co-o-o--o-o-o o-o-o--o-o-o o-o-o--o-o-o
I suspect concrete railway sleepers are not subject to tensile loads under normal use, and would break if you used them as such.
te railway sleepers an wondered what load they would take. Car, transit or concrete truck. Is anybody up on structural engineering. I am using 300x300 x1500 concrete blocks as abutments.
2600 long, the foundation is rock. I am aware these are not as new. The sm allest section of concrete, as in most concrete sleepers, is in the centre at about 230 x 140 with 2x3x3 strands of probably 8mm but say 6mm wires at 40mm c-cbridge will be 2 x 300mm blocks high at most.
is an issue. Thanks for the sensible questions.
I imagine they'd be stronger on their edge, no ?
I suspect they wouldn't need the rebar if that were true.
I would not use these personally .. they are designed to take a load at
2 points from above and transfer to an even bed.You want to take load on to 2 points with unsupported span.
Why not just cast using RC and rebar, even if you do it in 2 or 3 pieces.
The question is 5 months old.
And the OP even told us how he'd solved the problem.
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