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· Stay-at-home GC
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Discussion Starter · #1 ·
Posted some pics in my album of the landscape project I am tackling this summer.

Four phases, 13k in materials, Engineered walls and a pond wooohooo.
 

· Stay-at-home GC
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Discussion Starter · #2 ·
Engineers jumping ship

Haven't been able to get an Engineer on board. At some point I am just going to have to go forward without their blessing.
 

· Stay-at-home GC
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Discussion Starter · #4 ·
Thanks,

I really think the guys I've had out here to look at it are over-complicating it.

It's been stable for 40 years with nothing but a few crumbly dry-stack walls holding it in place.

Now I want to replace all the rotten sandstone with CMU core poured with rods and footings and suddenly its a problem? Planning on backfilling with enough gravel to start my own quarry, weep holes, perf pipe, tie-backs and pilasters if necessary. Throw in a few bond beams and pin the whole thing to the bedrock 12" below grade. What could go wrong?

I don't understand. Is it going to be easy? No. Is it doable? Yes
 

· Stay-at-home GC
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Discussion Starter · #6 ·
Sorry, I guess I was ranting a little and forgot to ask a question.

Anyone ever sprayed Quikrete's Quickwall Surface Bonding Cement through a mortar hopper?

Trying to guess the PSI and CFM. Going to go research it now, as soon as my coffee cup is full.
 

· Stay-at-home GC
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Discussion Starter · #7 ·
Guess I'm just looking for someone to spit-ball ideas with.

If you read through my posts you'll see I have just enough construction know-how to get myself in trouble (hence my signature). This is my first real dirt project and I'm sweating it.

I know there are many retired pros, altruistic pros and hardcore DIY warriors on here that might know a trick or two.
 

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It does seem odd that you selected a CMU wall in your cold climate where deep footers are needed. But maybe the shallow bedrock eliminates the need.

I live in a mild climate where deep footers are not needed. CMU walls are common and many of them fail. The construction of walls is not controlled here or permits required. A lot of walls are DIY.

Around here most CMU walls fail because of inadequate width of footer, inadequate steel re-enforcement from footer to wall, and lack of vertical steel and concrete fill in the block voids.

Block masons often build walls that fail when they do as they would for a house foundation. Walls for a house have the added weight of block above the ground as well as the house, and the house floor locks the top of the wall for lateral stability.

Homeowners are often successful with 2 ft high walls, but a DIY wall more than 4ft almost always fails. Homeowners just do not understand that a 4ft wall has many more times the force against it than does a 2ft wall.

The sketchups you provide do not show the height or separation between walls.

I wonder where you are with the topo map? Maybe you dropped it, since you weren't successful hiring an engineer. The map was important to the engineer and is even more so to you. Here is an early map of my property before I started my wall project. (walls in blue, about 400 lf)

 

· Stay-at-home GC
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Discussion Starter · #9 ·
Sorry, sick PC and fighting with resizing the jpeg image.

The 2' Topo is in my albums now.

I met with a Landscaping Pro yesterday and we had a good "ideas session".

I think the 3rd wall is going to go bye-bye and be replaced with a dry-stack "aesthetic wall". We'll make up the difference in the heights of the other two

The top wall is going to become a counterforte design, which will (hopefully) allow us to move the wall farther forward on the footing without creating tipping issues.

Had a Commercial/Civil Engineer out on Friday. Good vibes that his firm might be interested. Next Engineer is Thursday

I'm also chronicling my sad saga over on Ground Trades Exchange if anyone is interested in following it over there.

Working today on modifying my SketchUp files to reflect the new directions. Might also look into having hyper-accurate 1' interval Topo done of the back hill.
 

· Stay-at-home GC
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Discussion Starter · #10 ·
Another idea that emerged is the possibility of using Aerated Cellular Concrete products where possible. The step treads seem especially well suited to this.

Anyone heard of a landscaping step tread made of this product? Opinions on durability?
 

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The topo survey gives a good general idea of the site. The graphic resizing did make the details un-readable. Maybe you could give it another shot? Try cropping the graphic to just the area from the street to just past the project boundary. Then resize the cropped graphic.

There are elements to the topo that lead me to believe it was part of a plan for the property rather than a post construction survey. If this is true, the actual grades may differ from that shown on the survey.

I haven't seen where you have said what the wall heights might be.

If the contours shown on the graphic are on 2ft intervals, then I think it is unlikely this project can be completed for $15k even if all labor is free.


I read your posts on the other site and i agree with your comments on the look and cost of SRW versus masonry walls. You also said "I have (am) considering forming all of the walls and pumping in but I'm not comfortable with building my own blow-out proof forms. With such massive walls and heights, its to much for DIY Guy." DIY'ers do suffer blow-outs, simply because they fail to understand the pressure that wet concrete exerts on forms, especially on tall pours. But it's not rocket science. A little study of the way pros use snap ties would lead to success. Or you could do as I did and build your own bolt together forms. I've never come close to a blow out.

There are a lot of good reasons for SRW in a cold climate. But once you commit to a masonry wall, I think cost, strength, and skills needed favor a poured wall over CMU.
 

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Discussion Starter · #12 ·
Never did have any success with zooming in the Topo. If anyone is interested in either the Topo or SketchUp file, PM me your email address and I'll send them over.

Power was out all day yesterday and finally came on this morning. So today is adding buttresses and counterforting to the walls.
 

· Concrete & Masonry
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Wow, certainly an aggressive project you have in mind.

Maybe a dumb question, but have you completely ruled our a segmental retaining wall system? There is lot's of information on them available from the manu's, and plenty of engineers who seem to be comfortable in designing the systems. They also have quite a bit of aesthetic options.

If your set on CMU constrution, I'd certainly look at an "Ivany" type block:

http://www.ivanyblock.com/

Extremely strong system for the heights & loads you're apparently working with. Even then though, CMU is going to be alot of work. As for a sprayed finish, I textured my entire shop (after a smooth coat of plaster) with a drywall hopper gun and a strange mix of mortar. It looks like a fairly rough "orange peal" finish, and hides quite a bit of the plaster imperfections.
 

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The aerated concrete you mentioned may have extremely variable properties because of the different manufacturing processes.

The most common type is autoclaved aerated concrete that has been around for decades in Europe. It is available in various densities, but it is genrally not good for abrasion.

Your engineer may also look at segmental retaining wall block (split, colored) that are usually referred to as SRWs that are not laid on a concrete footing (8"-12" thick compacted base instead) with no mortar, rebar or grout allowed. The walls can be straight, curved (inside or outside curves) and can be built with decreasing heights. The tallest wall I have seen is 40' and I also saw a series of walls 6 miles along a freeway with high walls (20' -30') with additional walls offset back that were between 5' and 15' high. It is definitely an engineered project to determine the length and spacing of the geo-grid fabric that is used for the soil retained. Hundreds of millions of sf of this construction has been built internationally. there are 4 major systems (Allan, Anchor, Keystone and Versalok) that a good engineer will be familiar with and can look for applicability for your project.

Dick
 

· Stay-at-home GC
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Discussion Starter · #15 ·
Thanks guys.

Unfortunately the Customer (my wife) is dead set against anything SRW. I like the Rosetta Stone Outcroppping collection from an install perspective but she said it would feel like we were living in a zoo display.

After thinking about it last night I'm starting to lean away from the CMU and toward a monolithic concrete pour.

With the CMU's I'd have 3 different mixes and 3 different set/up tear/downs.

1. Footing mix
2. SBC Mix and sprayer
3. Core grout

With one big pour I could save a-lot of steps.

Still sweating the wall forms though
 

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Earlier in this thread bedrock is mentioned to be at a shallow depth. One possibility not talked about is removing all of the soil and loose rocks over the bedrock. The result might be a pleasing look of a stone cliff serving the same function as a wall. A short wall might be needed at the top to prevent soil being washed onto the lower bedrock. And rock planters could be located at spots on the cliff to provide a place for plants.
 

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Utilizing the site topo provided, I imported a small strip of grid and calibrated the scale to one of the lot boundary dimensions. Next the grid strip was relocated to a position through the house and up the slope.

A part of the site topo was then imported to a grid and scaled to fit it. A line was selected (red) as a x-section location. The location of the contour lines was then used to plot a profile on the grid. It shows a house dimension front to back of 28ft. and slope behind the house to be about 45%.

This is a very steep slope and I would expect there to be heavy erosion trails down it.

The profile can be used to consider size and location for walls.

 

· Stay-at-home GC
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Discussion Starter · #18 ·
Very nice! I hadn't seen that before.

We do have a few areas where the sandstone walls have slid aside and created mini erosion washes.

The original owners had a lot of the hill overgrown with Crown Vetch which is devil weed unless you have a slope you're trying to hold. Might replant some this Fall.

Thanks so much for your help. I'm kind of embarrassed you spent time on my project. I was just expecting guys to point and laugh and looking for a place to rant.
 

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And thank you for the kind words. I’m retired and have more time for idle pursuits than most. It was I that recommended you get the topo map done, knowing full well that you would not how to use it as a design tool.

There are many homeowners that need retaining walls. Most will fear building one. Maybe that’s a good thing because most homeowners fail to understand he immense pressures on walls higher than 3 feet. If you continue to post your efforts at doing this project, it will likely aid many people to understand what is involved in building a wall. A forum is a place where we learn from each other.

Any number of walls could be chosen for this site. I’ll look at one possibility. Your first concept for the site was three walls. Below I select possible locations for the walls on the profile such that they span the vertical height needed of around 15 ft with a relative equal height for each wall of 5ft. I make the locations and depth to the footer keeping in mind that you said the bedrock was about 1ft deep.




I note the ground elevation at the above wall locations of 1158.8, 1163.5, and 1169.0. Turning to the plan view, I can now draw the walls, holding to the contours. The walls can be shorter or longer than those shown. Note that I have turned the ends of the walls back into the slope to match the elevation for the top of each wall.





Since you seem very capable with sketchup, I wonder if you can import this type of graphic and develop a 3d version.
 

· Stay-at-home GC
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Discussion Starter · #20 ·
One possibility not talked about is removing all of the soil and loose rocks over the bedrock.
I like this idea and am looking into it for the left side of the house. We are building a deck there in Phase III and I will probably push that left hill as far back as possible, allowing for some storage/shaded area under the deck.

The Plan view looks great. I am working on importing the Topo into SketchUp now.
 
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