# Pitched stone construction



## Walt Dizzy (Aug 18, 2003)

I read about this technique in my IMBA Trail Solutions book and thought, "Well that's interesting, wonder if it will ever come in handy?"

The short answer is "Yes". 

We are adding a loop at Blue Mound State Park (WI) this summer, and started work on the second switchback on Friday. The switchback needs a retaining wall because the slope we're working on is too steep for a climbing turn. In the new area we are working in there is a shortage of large rocks. There is a fair amount of flat limestone rocks in the nearby ravine.

We used up all the larger (200 lb +) rocks in short order. On one end of the wall, I started building a second course by pitching (placing up on edge) the smaller rocks above and inside the large ones. They went in like a dream and were...well rock solid!

On the other end of the wall, my project partner was being closely supervised, and was told to stack the rocks like pancakes. 

This morning when we went out to resume work it was obvious with the most casual inspection that the flat stacked wall was much weaker than the pitched construction. We ended up tearing out most of the stacked wall and rebuilding it.

Our turn is looking great, can't wait to ride it!

Walt


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## formica (Jul 4, 2004)

photos?


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## dburatti (Feb 14, 2004)

Nice! Did you take pictures during the construction to show progress? I'd love to see them. I think rock work is my favorite aspect of trail building. Fortunately, we have plenty of rock here in central Texas.

We built a rolling crown switchback with Mark Schmidt and Lora Woolner of IMBA a few years ago. We didn't pitch the stone, as our boulders were big enough. I'm glad to read that pitching the stone for a crib wall works in case we have to do that.

Here's the switchback. It's a little over 3' high at its highest on about a 30% slope.

Dewayne


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## Walt Dizzy (Aug 18, 2003)

*Beautiful work*

dburatti,

The lower leg of the turn looks so high compared to ours. We're having problems finding enough fill to build it up as high as I'd like.

Day 1 we ran out of dirt that was close enough to throw in from the upper leg.

Day 2 we humped a wheelbarrow out, but we worked four hours and still ran short of fill. (We only had 3 guys that day-shorthanded IMO).

The problem is that we made a nice, wide turn and as we fill the lower leg, the area to fill gets w-i-d-e as the filled area gets higher on the slope.

I think our best bet is to fill the area inside of the tread with topsoil, and save the clay for the tread.

Any wisdon to pass on?

Formica,

Lots of pics of people posing with tools, I'll try to get one of the rock work next weekend.

Walt


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## dburatti (Feb 14, 2004)

Walt,

We had a great borrow pit within 40' of the switchback and also plenty of rock to use as filler on the bottom layer. If you can scrounge up rock, it works well. Just make sure to compact the fill dirt well as often as you can.

BTW, it took us 140 man hours (20 people working about 7 hours each in one day) to build that structure. It's defintely solid and will last a loooong time!

If you have any specific questions, please feel free to post them or email me at dewayne @ talontrails.com (without the spaces, of course.)

Dewayne



Walt Dizzy said:


> dburatti,
> 
> The lower leg of the turn looks so high compared to ours. We're having problems finding enough fill to build it up as high as I'd like.
> 
> ...


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## Walt Dizzy (Aug 18, 2003)

*Sounds about right*

Dewayne,

What you're saying about the man-hours makes sense. We have about (3x2)+(6x4)+(3x4)=42 man hours into our turn at this point. (I forgot to include an initial day spent harvesting rocks.)

Not having a wheelbarrow on the first day of construction wasted a bunch of time. I totally underestimated the amount of fill needed, and how far we'd have to go for it. I'm going to take my own wheelbarrow out and leave it for the duration. We have two more rock walls to build in this loop.

I don't think we have the luxury of making a borrow pit, but we should be able to get plenty of fill from the bench cuts leading in and out of the turn. Getting the rocks for the wall has been a challenge too. The slope above the turn is completely rock free, we've had to collect them from a ravine below the turn. The ravine sides are steep, and we have to winch the larger ones up using a chain sling and come-along. Fun engineering, but not fast work!

Thanks for your thoughts.

Walt


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## bitflogger (Jan 12, 2004)

formica said:


> photos?


Photos in this thread:
http://forums.mtbr.com/showthread.php?t=189411

What I'll call the front and top needs more rock and fill here. It's a chore just to get tools to where this is as well as rocks out of the stream bed. Mr. Dizzy's hauling the wheelbarrow there really helped.

FWIW: A scout troupe volunteering really helps accelerate the rock farming.

With pitched stones and not I make sure the ones on top have some purchase as layers and fill build.

It has not been as easy and as accurate as landscaping work I've done due to where we're working and the materials we get. So far what Mr. Dizzy and I have been doing seems to hold up or what we have fixed seems better the next season etc....


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## imba_pete (Aug 9, 2005)

*Example of Really Old Stone Piching*

Thought you guys would enjoy this photo. It is an example of stone pitching from the tiny mountain-top fortress town of Monsaraz in Portugal. I was vacationing there last week on a bike tour. This town is ancient, and every street and alley is paved like this. Some of the stonework is over 500 years old. Many old towns in Europe are cobbled, but stone pitched streets are not as common. You can see more at http://www.monsaraz.com.pt/

Pete


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## Walt Dizzy (Aug 18, 2003)

*Nice Picture*

Thanks, imba_pete.

I'm not quite arrogant enough to believe my work will last 500 years! But I'd like to think that my trail will still be in use after I'm too old to ride it. Stone work is way cool. One of the less selfish things I've done recently is to devote myself to hauling rocks and dirt and turning most of the construction over to my partner.

I feel priveleged to be allowed to build this trail. I can't believe people aren't falling over themselves to make it happen, but unfortunately it's not so.

Walt


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## Walt Dizzy (Aug 18, 2003)

*Update*

William (the guy in the picture) and I made a lot of progress on our turn yesterday. The back or apex of the turn is built up a lot higher now, and is looking good. We made the effort to gather a lot of rocks to make an adequate retaining wall, and we moved tons of dirt to build a well sloped ramp. lt's nearly done now, and I have a lot of confidence that it is built well.

Thanks to everyone for their comments.

Walt


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