Concrete wall thickness

[mike65072]

I'm about to replace an older RR tie retaining wall with a poured concrete wall. The new wall be about 12' high for about 20' then turn 90 degrees and taper up hill for 40' to a final height of about 2'. The virgin soil is compacted clay and rock. There will be a proper footing, at least 4 dead men, multiple weep holes and plenty of steel in the concrete. The backfill will be 2" clean rock. Occasionally a car will park on the backfilled area for a few hours at a time.

Some of the contractors are bidding an 8" thick wall, others a 10" wall and one a 12" wall. I realize more is better, but the cost goes up dramatically with each 2" increase in thickness. Will an 8" wall be sufficient?

[wrench spinner]

Re: Concrete wall thickness

I think you need a geotechnical engineer to design the wall for you... NOT the contractor. Once you get some plans then have the contactors rebid the job with all bidding the same thing.

[toolaholic]

Re: Concrete wall thickness

I think you need a geotechnical engineer to design the wall for you... NOT the contractor. Once you get some plans then have the contactors rebid the job with all bidding the same thing.

What He said geo tech. and struct. eng. Not civil

[BHD]

Re: Concrete wall thickness

I think the design of it is more important than the raw thickness, and how it is anchored, was well as it is reinforced, as you could easily have a 30" thick wall and if the earth moved behind it, the wall would not hold it it would either move or tilt, and if the 8" wall is properly anchored and reinforced it should work, now a 8" wall many need more anchor point than a 12" wall would, but for cost one would have to have it designed for proper and the lower cost, for the project, depending on the soil types 12 foot is a lot on retaining wall,
some different types of walls show at link,
Retaining wall - Wikipedia, the free encyclopedia
some info, picture from below link,
Retaining Wall Design - The Concrete Network
a cantilever with reinforcements in the wall
304. L-Shaped Retaining Walls

[toolaholic]

Re: Concrete wall thickness

In the Bay area we are in a serious seismic zone. Hence lots of time spent with Geo techs. and Struct. engineers. NO Found. walls , or retain walls are built without them.
When We have excavators drilling 30 ft. 18" diameter peir holes they record the spoils coming out of each hole. And remember a 6 ft. high retaining wall behind a hillside home is engineered for the sur charge going up the hill at a 45 degree angle!
That 6 ft. high wall may be holding back 15 ft of hillside. I strongly suggest You don't roll the dice ! Good luck tool

[ChuckDee]

Re: Concrete wall thickness

in the bay area we are in a serious seismic zone. Hence lots of time spent with geo techs. And struct. Engineers. No found. Walls , or retain walls are built without them.
When we have excavators drilling 30 ft. 18" diameter peir holes they record the spoils coming out of each hole. And remember a 6 ft. High retaining wall behind a hillside home is engineered for the sur charge going up the hill at a 45 degree angle!
That 6 ft. High wall may be holding back 15 ft of hillside. I strongly suggest you don't roll the dice ! Good luck tool

holy ****!


____________________
"I have busted more hippies' noses than all the narcs in the free world." - Ted Nugent
Chuck Dee - AKA Chris
www.rhinobldg.com

[toolaholic]

Re: Concrete wall thickness

holy ****!

I use to build in Mass. 1970s whole different ball game in the bay area. Coming out of the hole before a stick of lumber is over a hundred Grand! i1970s back East I was building nice capes for $30,000

[joana]

Consulting an engineer is the best option, mate. I hope you did the right decision by this time.

All the best!

I can do every small jobs, just name it.

[shalam]

I'm about to replace an older RR tie retaining wall with a poured concrete wall. The new wall be about 12' high for about 20' then turn 90 degrees and taper up hill for 40' to a final height of about 2'. The virgin soil is compacted clay and rock. There will midasbuy rent a car dubai blue world city zameen

be a proper footing, at least 4 dead men, multiple weep holes and plenty of steel in the concrete. The backfill will be 2" clean rock. Occasionally a car will park on the backfilled area for a few hours at a time.

Some of the contractors are bidding an 8" thick wall, others a 10" wall and one a 12" wall. I realize more is better, but the cost goes up dramatically with each 2" increase in thickness. Will an 8" wall be sufficient?

You must consult with a good practitioner engineer for this sort of thing, as it will ruin your wall and the cost which you want to save will be double.

[madmardigan]

www.handymanleander.com/fence-care
You must consult with a good practitioner engineer for this sort of thing, as it will ruin your wall and the cost which you want to save will be double.

I would agree on this advice since I've been there and the worst scenario happened.

[MaryRose]

Re: Concrete wall thickness

arlington drywall pros

What He said geo tech. and struct. eng. Not civil

I agree.