# Frost Heave (and ladder roadbed supports)



## Scottychaos (Jan 2, 2008)

I guess I dont really understand what frost heave is..or how it works exactly..
I know freezing water expands, and pushes things around..but..

I was just reading through Paul Race's ladder roadbed article:
http://www.btcomm.com/trains/primer/roadbed/ladder1.htm

and he said:

Drive the posts into the ground through the roadbed far enough to prevent posts from tipping. Space 2 foot maximum. Do *not* sharpen the end of the post. Sharpening the post like a stake to make it easier to drive will cause the post to push out of the ground later during frost heave. A square end on the post will minimize this.


This does not make sense to me..
it seems the opposite should be true..
if frost heave is "pushing" things out of the ground, wouldnt a square end offer a *better* surface to push against than a sharp end?
the square end has more surface area to work with..

so what am I missing?

can anyone explain what frost heave is exactly?
and why it effects some things, but not others..

im considering the ladder roadbed for my railroad, and I dont know if I should factor in frost or not!

thanks,
Scot


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## cmjdisanto (Jan 6, 2008)

Scot,

I think it has something to do with the way the point get squeezed in the ground. The tapered end works against the ground making it easier to push it up. With that said.......I would have to say YES, you have to take into account heave if you use a ladder system or sink any solid material into the ground. 

Having lived in your neck of the woods for a couple years (remember I mentioned I was in Geneseo for 3 years) I can say that no matter what you do, in regards to driving any form of stake into the gound for support, if you do not get below the coded 4ft frost line that is in that area...........you'll have issues. And yes it is 4ft or at least that's what we had to set fence posts at when we installed the fence. 
Just for an example,Our foundation for the house was started at 11ft below the grade. That was 3ft of concrete for the footer and 11 courses of CMU Block. Only 3 courses were visible above grade. I also did one of those Hardware cloth fences that use the green metal stakes that have an end like an arrow. First winter freeze and spring thaw, they came up. I could only get them to 2-1/2 ft. because of the soil rock fiields. If you head out into the country, every spring you can see rocks and in some cases boulders that have come up from under the ground because of the heave. 

When we were planning the layout we had planned a free floating road bed (and type we still use). It would seem to me that ballast shifting would be a whole lot easier to deal with than the support system heaving every year.


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## Dougald (Jan 2, 2008)

Scott

Frost heave is simply the expansion of water that is trapped in the soil. As it expands it pushes up on everything above it and causes a sortation of material. The biggest items are pushed higher while the smaller material falls around it. Just like when you shake a bucket of pebbles and gravel, the larger pebbles rise to the surface.

If a post is driven below the frost line deep enough to anchor the end of the post, then the ground will heave and rise and fall around it, theoretically leaving it unscathed. I say theoretically because often side stress will cause the post to tilt. Also, sometimes the post is attached to a large flat object (like your roadbed ladder for example) and the heave in the ground may lift the ladder, essentially levering the post out of the ground.

There are solutions. I always recommend an examination of the local building code to see the specs for building a deck - a ladder is a narrow deck. Those standards will assume that you do not backfill so that your ladder is actually buried in the ground but that there is a small space for expansion and frost heave. Those standards will permit a freestanding structure on stable undisturbed compacted soil or will give the depth for setting in posts. Since digging postholes on 4 foot or maybe 6 foot centres (assuming your ladder is sufficiently strong - most guys build them flimsy!) is very hard work, most of us opt for the freestanding approach wherever we can.

The frost line here is 42 inches and setting 4x4s to 48-52 inches (in concrete no less) is not my idea of a good time. I use the deck blocks recommended by the code for a freestanding structure and have had no trouble with frost heave. The ground still heaves - even compacted soil will heave during the winter. But the whole track roadbed heaves and then resettles without causeing track distortions or problems. This is the equivalent to your deck being heaved very slightly and resettling in ways that do not give trouble. That is of course why the code allows that form of construction.

Should you decide to go other rooutes, a concrete roadbed is essentially a sidewalk in the code. Stick to the standards and your roadbed (sidewalk ) will be less likely to crack. If you trench and use stonedust, see what the code says about that form of walkway or driveway construction and you will understand why the typical modeller's 6 inch deep trench lined with crushed stone and stone dust requires such enormous maintenance each spring due to frost heave.

The long and short of it is ... if you wish low maintenance, then the roadbed must be done right. The building code is there for a reason. Though our track is not heavy, the roadbed must not deflect abruptly due to frost heave. Following the code will give you the best chance to avoid long term labourious maintenance. It is this reason that has led all OVGRS members who have laid track to install an elevated roadbed system on deckblocks as the least costly and labour intensive way of producing solid trackwork.

Regards ... Doug


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## Scottychaos (Jan 2, 2008)

interesting..thanks guys.. 

with all these recent ladder roadbed threads..no one is using it in cold climates? 

if ladder roadbed is no good, because of frost heave.. 
and the traditional "floating in a trench of ballast" is also sub-par..because of frost heave.. 
whats left? /DesktopModules/NTForums/themes/mls/emoticons/sad.gif 

(and no, im not moving to Arizona!  not yet anyway..) 

thanks, 
Scot


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## SteveC (Jan 2, 2008)

Scot

Frost heaving isn't proving to be as simple as one would think, you may find the following interesting and provide additional areas to explore.

*http://en.wikipedia.org/wiki/Frost_heaving*


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## wchasr (Jan 2, 2008)

Scot, 
I think the point is that in cold climates where teh ground freezes and thaws (especially in the spring) things are going to move. Some methods of construction minimize the amount of labor to correct things once the cycle stops. Following local building code methods will minimize the amount of work later. I'm seriously leaning toward a totally raised layout outdoors myself built like a deck on the deck blocks. IF it moves, it will mostly move together as a single deck. i amy do some raised planters as well and connect with bridges but for now no building is taking place save a possible portable live steam track? If I do raised planters they will be compacted as best as I can possibly even renting a motorized tamper for a wekend? 

Chas


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## Spule 4 (Jan 2, 2008)

Frost heave did in our SM32 railway up in Ohio 20 odd years ago, we did a ladder/stake type roadbed, and ended up with a roller coaster.


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## NTCGRR (Jan 2, 2008)

heres a sign from heaving 









This is after winter in thaw. during winter runs I have no problems , its when its coming out of the ground.This sign was stuck in the frozen dirt during winter.


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## Trains (Jan 2, 2008)

Scot,

I installed mine last year, and it came though the winter just fine. I drilled down with a 3" auger 24". Cut my 1 1/2" plastic pipe about 4" longer
then needed. I drove it into the ground till it was level or up or down a little for my grades. I have a small round bubble level I put on the top of 
the pipe and leveled side to side. Then I back filled the hole a little at a time and tamp the dirt.


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## Scottychaos (Jan 2, 2008)

Thanks everyone! 

I think I might build about 24 feet of wall this year, (6 four foot panels) just as a test.. 
using the 2x2x8 boards as the walls, and 4x4's in the ground as posts.. 

maybe build a bit of ladder roadbed too, just to see how it holds up through next winter.. 

then, if everything still looks good next spring, I will be 25% done!  
and if not, I can try something else for the remainder of the railroad.. 

thanks, 
Scot


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## Scottychaos (Jan 2, 2008)

No one has any idea what this means? 

Drive the posts into the ground through the roadbed far enough to prevent posts from tipping. Space 2 foot maximum. Do *not* sharpen the end of the post. Sharpening the post like a stake to make it easier to drive will cause the post to push out of the ground later during frost heave. A square end on the post will minimize this.


I think I will send Paul an email and ask him.. 

Scot


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## Greg Elmassian (Jan 3, 2008)

Think of holding a round rod in your hand... squeeze it... you just get a tighter grip... now taper the end at 45 degrees... hold that end in your hand and squeeze... it will try to pop up out of your hand. 

That's the theory on not putting points on the ends of stakes that are above the frost line... the pressure in the ground from freezing squeezes in every direction... 

Regards, Greg


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## wchasr (Jan 2, 2008)

Besides NOT putting a point on the end think about what Marty said about pouring concrete footers or post bases. They should be tradezoidal with the larger side towards the bottom. Partially for the stability it provides but ALSO so that it becomes "locked" into the ground and is therefore less likely to move with frost heave. Think of a "keystone" shape at the base of the posts. Then buried again. It's gonna be VERY stable.

Chas


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## pdk (Jan 2, 2008)

Doug's post is right on the money as usual imho. I can only add that where frost heave is concerned chaos theory applies, as it has proven to be very unpredictable. Examples abound of work "done right" that did not withstand frost heave. 


For outdoor lines in cold climes like ours, we have to go big or go home -- deep foundations; lots of concrete. OR float the track in rock dust/limestone screenings/crusher fines and be prepared to top up the ballast every spring, and do periodic/constant maintenance to keep the track level. This, I happen to enjoy. But would I enjoy it if I had a huge layout like some of the guys here? Not so much.


To me, frost heave is a small price to pay for the invention of the world's greatest sport -- hockey.




















Posted By Scottychaos on 03/31/2009 12:54 PM
interesting..thanks guys.. 

with all these recent ladder roadbed threads..no one is using it in cold climates? 

if ladder roadbed is no good, because of frost heave.. 
and the traditional "floating in a trench of ballast" is also sub-par..because of frost heave.. 
whats left?







" align="absmiddle" border="0" /> 

(and no, im not moving to Arizona! " align="absmiddle" border="0" /> not yet anyway..) 

thanks, 
Scot


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## Trains (Jan 2, 2008)

It gets mighty cold in Omaha!


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## aceinspp (Jan 2, 2008)

Well if you want to play trains outdoors than be prepared to fight the eliminate just like the big boys. I don't mind the maintenance as I grew up around maintaining a RR. To me that's part of the fun of RRing and a challenge. Even had frost here this winter which is unusual. One can spend a great deal of money on making your RR bullet proof. I'll stick to the routine maint. Later RJD


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## SE18 (Feb 21, 2008)

according to the above wiki link: http://en.wikipedia.org/wiki/Frost_heaving 

sand and clay are less suceptible to heave than silt. Simply dig down below the frost line and fill the trench with sand or clay. Problem solved


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## Dougald (Jan 2, 2008)

Digging below the frost line is not practical for the trench method in cold climates. The city does not find it practical to dig below the frost line for sidewalks either when the frost line is 42 inches down. The local building code here specifies (depending on soil) that trenches for pathways and sidewalks be cut 15 inches and filled with stone dust on crushed stone. Most modellers prefer to only trench 3 or 4 inches - and that led to my comment that those railroads required plenty of spring maintenance in our climate.

Regards ... Doug


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## NTCGRR (Jan 2, 2008)

so whos photo is the bay window? I know it probably was hung with cables from the floor joice. But the bottom needed to be insulated ,wraped around with a 2 X 4 and supported with braces off the wall. 
I was wondering if the brick was done on a brick leadge or angel iron?


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## sheepdog (Jan 2, 2008)

The first thing I have to do in the Spring is check and adjust the ladder level..... Usually side to side is the problem.

Here is a pic of one of my outdoor lights after this winter.










Yes, it was upright in Oct. And yes, it has a pointy end.

Craig

Edit: I also installed one of those 'invisible dog fences'. Had to repair it at least once a year due to frost heave or dry cracking of the soil. Thankfully, it worked long enough for the 'Cool Dog' to figure out the boundaries........ She does not know it has not worked for years...


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