AREMA Rail Design - Spanning between posts without supporting beam

[fracture_point]

I'm working on a project where we are trying to determine how far a 136lb AREMA rail can span between posts.

The architect wants to maximize the spacing between posts just using a column cap, but we are trying to assess how far these things can span without have a support W-beam beneath.(see attached for section).

Loading:
Arema requires considering an arrangement of either 80,000 for an E80 Cooper loading, or 100,000lb for 4-axles, whichever produces the most critical effect. AREMA Chapter 15 also mandates we consider 25% of a wheel load acting laterally, is my assumption correct in the sketch that we should consider the 25% point load acting either way (longitudinally or transverse) to the posts?

How can I determine the capacity of this AREMA rail? Is it just a similar case of getting the section properties of the rail and designing like a regular beam? Any caveats that I should be aware of?

 

[dik]

What do you require... E80, also? If not what is the actual wheel load and what is the wheel spacing between these loads?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[fracture_point]

What do you require... E80, also? If not what is the actual wheel load and what is the wheel spacing between these loads?

An E80 train set, so the two loading situations I need to consider are below (whichever causes critical loading).

 

[EdStainless]

I was in an old railroad roundhouse once. They had access pits for working belore locomotives.
The heavy rails ran into the building, and were supported by pieces of rail that were vertical every 8-9".
You could reach through them but to access the other side you had to walk to one of the places that had a 30" gap and beam supporting the rail.

You can run the section properties on the rail, but vertical + lateral load you are looking at a beam under the rail.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[SlideRuleEra]

How can I determine the capacity of this AREMA rail?
1) Is it just a similar case of getting the section properties of the rail and designing like a regular beam?
2) Any caveats that I should be aware of?

1) That's what I would do.

2) See if impact or longitudinal loading has to be considered.

Check rail deflection and keep it very low. The rail is probably continuous over several supports, but base calculations on the worst case which is likely a simple span assumption.

http://www.SlideRuleEra.net

 

[rb1957]

how long is the rail ? how many bays ?? (is it a continuous beam, or a single simply supported span ?)

Your alternative loading seems much more severe ... E80 is 8000 lb/ft, alternative is 400000/16 = 25000 lb/ft.

Is the "E80" diagram correct ? I get 10000 lbs/ft (564 kip/56')

another day in paradise, or is paradise one day closer ?

 

[fracture_point]

1) That's what I would do.

2) See if impact or longitudinal loading has to be considered.

Check rail deflection and keep it very low. The rail is probably continuous over several supports, but base calculations on the worst case which is likely a simple span assumption.

The lateral load of 25% axle load has to be considered in either lateral direction. Yep, I've kept it to L/500 which is client's requirements (treating it as simply supported whereas it will be continuous).

how long is the rail ? how many bays ?? (is it a continuous beam, or a single simply supported span ?)

Your alternative loading seems much more severe ... E80 is 8000 lb/ft, alternative is 400000/16 = 25000 lb/ft.

Is the "E80" diagram correct ? I get 10000 lbs/ft (564 kip/56')

It's long and continuous. The 8000lb/ft is for trailing cars I believe, so you would consider that behind the axle loads of the train.