Live Load MSE wall supporting Railway

[MSEMan]

I'm looking at a MSE wall supporting a railway spur (new construction). If I apply the live COOPER 80 load, as a conventional live load, I get a sliding problem since the live load would only be applied over the retained fill for stability/sliding analysis not the MSE wall. However, it seems to me that the conventional analysis is actually meant for live loads whose position is uncertain (i.e. travelling on one of a number of lanes.) I know exactly where this load will be (on the tracks hopefully), so why shouldn't I simply analyze the cases with the Cooper 80 and without it to determine the worst case?

 

[Panars]

The Cooper E-80 load is a concentrated vertical load applied over a discrete area. It is not a uniform surcharge load like the live load surcharge for traffic. So I think you would be correct to analyze the wall with and without the E-80 load and use the worst case.

 

[jdonville]

MSEMan,

I agree with Panars. Treat it as a discrete strip load. That having been said, only the portion of the live load located within the Rankine active wedge will impart lateral forces on the MSE reinforced mass. You could use Jarquio's method to compute what this load is and the effective point of application rather than assuming a uniform lateral load.

Jeff

 

[PEinc]

MSEMan,

You did not describe the geometry of the situation. Is there one track or multiple tracks? Is there a slope between the face of wall and the nearest edge of tracks? Is it possible that the track could be moved or shifted closer or farther away in the future?

If the ground surface behind the wall face is flat, it seems to me that you may need to design your wall with the track over the reinforcement strips (near the wall face) and with the track just behind the back end of the reinforcement strips. You never know where the tracks may be located in the future.

A Cooper E-80 surcharge on top of the grids will make you need heavier grids but won't hurt sliding. A Cooper E-80 surcharge behind the ends of the grids will increase the sliding force and lengthen the grids.

 

[garrettk]

I'm surprised the railroad is accepting the use of an MSE wall to support it's rails. My experience has been that RR companies will not allow the use of MSE walls except for end bents supporting bridges crossing over the tracks.

If you haven't asked this question of the RR company specifically it is worth the call. If it's a private track then the question goes away.

 

[CompositesKid]

Gentlemen-
I am a Manufacturer's Representative for a Company
that is producing Timber type products made from recycled
HDPE.(Post Consumer Plastics) They are producing greater flexural, tensile and
compressive tests results than the traditional wood.
They also probably would make an excellent electrical ground. I was hoping to get some input from the engineering
community as to whether or not they believe materials
such as Rice Hull Cellulose Fiber High Density Polyethelynes could effectively be used for RailRoad Crossties, Temporary Bridge Shoring and similar type applications. It seems they would out perform in seismic tests for elongation and sway as well. Looking for some oppinions of why or why not. Thank You

 

[miecz]

CompositesKid-

Your post has little relation to this thread. As such, it comes off a a thinly veiled advertisement for your product. Suggest you start a new thread.