Concrete wall near slab

[rospaw]

Have a 50x80 shop with poured slab. (slab is 7 years old a great condition) I need to put a drive in next to the shop. I have 22' between shop and property line. It goes from flat to the building slab at the front to about a 8' lower at the back corner (80') on the property line. In the back of the shop it is a pretty good slope about 8' down 30' behind the shop.
My thought is to cut down (dig) from 0 to about 8' along the side of the building then cutting back (dig) behind the building about 50' (the width of building) x 40'/ 60' for parking. Putting a poured or block filled wall.

Questions...
Does it sound like a plan that will work?
How close can get to the shop slab digging down 8'? (no fill, they cut top of mountain to build it.)
Poured concrete wall if so how thick?
Footing then block and fill block?
Interlocking retaining style wall?
Best cost effective way to do this?

Back up and PUNT?

Ideas? Thoughts? Will it work? Am i crazy???

 

[dwhee87]

An 8 ft high wall with fill behind it carries a lot of load. You might want to talk to a civil engineer to that them design something for you. Some of the retaining wall companies have staff engineers that'll do that as part of the work for little or no extra charge.

 

[Miguel Cervantes]

Have a 50x80 shop with poured slab. (slab is 7 years old a great condition) I need to put a drive in next to the shop. I have 22' between shop and property line. It goes from flat to the building slab at the front to about a 8' lower at the back corner (80') on the property line. In the back of the shop it is a pretty good slope about 8' down 30' behind the shop.
My thought is to cut down (dig) from 0 to about 8' along the side of the building then cutting back (dig) behind the building about 50' (the width of building) x 40'/ 60' for parking. Putting a poured or block filled wall.

Questions...
Does it sound like a plan that will work?
How close can get to the shop slab digging down 8'? (no fill, they cut top of mountain to build it.)
Poured concrete wall if so how thick?
Footing then block and fill block?
Interlocking retaining style wall?
Best cost effective way to do this?

Back up and PUNT?

Ideas? Thoughts? Will it work? Am i crazy???

You're playing with fire, or water which can be worse sometimes. The hydrostatic load behind that wall is a mighty force.

That being said, if you do a poured wall it will cost you as much for a footer as the wall itself. If you do a block wall it will fall as soon as you start back filling it.

Lay out the bucks and do an engineered modular block system wall, terraced so you can get the top wall high enough to create a swale behind it and turn runoff water.

Build the wall to manufacturers specs and don't take any shortcuts and you should be fine.

You try to go the cheap route on this project and you will have a mess on your hands.

Oh yeah, a couple more ugly facts. This wall will have to have a fence on top and has to be permitted. How bad do you need this parking?

http://www.keystonewalls.com/

http://northgawalls.com/

Look at these links and talk to the lower one. It's free and might help you avoid a colossal headache.

Disclaimer: no I don't know or work for either of those companies, nor have I ever done business with either.

 

[WayneB]

bearing for your slab is cone shaped and approximately 45 degrees outward and down.
8 ft cut translates to 8 ft out at toe of slope. Obviously you won't go to the edge of slab or rainwater will undermine your slab..
Assuming you leave 8 ft at building, 8 ft for slope, you are not left with much.
If you have to have a 'level' area, it would probably be cheaper to fill the lower area and compact it.

Sounds as if you have a challenging situation here.
FWIW: retaining walls 32 inches high or higher require fencing.

 

[rospaw]

Thanks for the comments and keep them coming!

Mex, The main reason for the drive by the building is to get to the back 1500' of the property. Where this is at the property sorta hour glasses to 300' wide. The other side is a no go due to having to go through the front yard/pool.

Yes, i do know that fences will be in order on any wall over a foot or two.

WayneB, Good post. I was wondering how much side load i had and the 45 deg outword sounds reasonable. The slab stops at the edge of the building. It appears when they cut the top to build house/shop ect that it is full of that shell type of rock. Brittle but still a good base. I am thinking that with that base i can cut a pretty straight 90 with my trackhoe. "IF " i can get a straight and built my forms only one sided full of rebar grid, 16" thick plus, drain system in bottom and poured it?
Guys this is all in the pre season. Not doing it until i get it checked out by pro. (dwhee87) (but will do it myself if done) I have seen 100's of old buildings, block houses ect with walls below the grade at the foot of the structure.

To get the straight cut..... Have a buddy that has an old trencher that digs about 8-10 foot. Use it to get my clean 90 then cut the other with big tracked skidsteer? or my 955?

again please shoot holes in my plan. WILL NOT hurt my feelings one bit!
Thanks all!

 

[WayneB]

I would encourage you to contact a geotechnical firm to bore and sample the subgrade. This information will need to be known by a civil engineer before a design can be formulated.

Are you looking for a paved or gravel driveway? A sketch of what you are thinking and some photos would possibly reveal a couple other options.

A segmented block retaining wall is sounding like a pretty viable option, however you must have room between the back of wall and the building to backfill and compact.
Another option may be a Gabion wall. Basically 12 guage wire baskets filled with rip rap and stacked together. Backfill is usually #57 stone.

I've had projects with retaining and gabion walls as part of the sitework, not so much retrofitting against an existing structure.

 

[rospaw]

I would encourage you to contact a geotechnical firm to bore and sample the subgrade. This information will need to be known by a civil engineer before a design can be formulated.

Are you looking for a paved or gravel driveway? A sketch of what you are thinking and some photos would possibly reveal a couple other options.

A segmented block retaining wall is sounding like a pretty viable option, however you must have room between the back of wall and the building to backfill and compact.
Another option may be a Gabion wall. Basically 12 guage wire baskets filled with rip rap and stacked together. Backfill is usually #57 stone.

I've had projects with retaining and gabion walls as part of the sitework, not so much retrofitting against an existing structure.

Quick sketch ......

 

[rospaw]

another pic

 

[calibob1]

Why not drive thru the shop and build more shop on?

 

[rospaw]

Pic

Don't know how to flip pic..... Any mod care to flip it for me.... Thanks

 

[rospaw]

Why not drive thru the shop and build more shop on?

Height is one reason...... T-top on boat, rollback... neither will fit. Plus having to keep a 10' x 80' strip open for when o want to get out. Good thought though!

 

[Jeff C.]

Here ya go rospaw.

 

[WayneB]

looks like a prime spot for a basement..
Definitely going to be a challenge, you needs professional help.

 

[rospaw]

Thanks Jeff

 

[calibob1]

How about moving the retaining wall toward the property line and making a fill,it's a little hard for me to picture.