A small interesting & practical retaining wall project to discuss
A small interesting & practical retaining wall project to discuss
(OP)
Hi, I recently got a small project for designing a small 8" block retaning wall that is about 2' to 3' above driveway. The driveway is close to the edge of the slope.
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1 1 Driveway side
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Before I conducted any design, I reviewed the soil report. 45 active and 250 passive are suggested. Also pier foundation is suggested as alternate for using 200 bearing. My design considerations are the following.
(1) How deep is the portion of the wall that needs to be below the top of the paver driveway? Maybe 2' to 3' ?
(2) What surcharge load should I use? 200 ?
(3) What is the size of the footing? Maybe 1' deep x 2'-6" wide as shown above?
(4) Should I provide drilled pier to prevent the wall from tilting and sliding? Min. 12" diameter x 15' deep? @ 6' max spacing?
(5) How far should the slope be? Maybe 2 to 3 times the height? Say 4'. Slope may be 2.5 to 1 (H to V).
Any suggestions or comments or ideas or points to make and discuss? Thanks
__
1 1 Driveway side
1 1
____1 1_____________
/ 1 1
/ 1 1_____
/ 1_______1
Before I conducted any design, I reviewed the soil report. 45 active and 250 passive are suggested. Also pier foundation is suggested as alternate for using 200 bearing. My design considerations are the following.
(1) How deep is the portion of the wall that needs to be below the top of the paver driveway? Maybe 2' to 3' ?
(2) What surcharge load should I use? 200 ?
(3) What is the size of the footing? Maybe 1' deep x 2'-6" wide as shown above?
(4) Should I provide drilled pier to prevent the wall from tilting and sliding? Min. 12" diameter x 15' deep? @ 6' max spacing?
(5) How far should the slope be? Maybe 2 to 3 times the height? Say 4'. Slope may be 2.5 to 1 (H to V).
Any suggestions or comments or ideas or points to make and discuss? Thanks





RE: A small interesting & practical retaining wall project to discuss
Respect how much deep to put the base of the footing, it depends on some factors such as on whether where you live the soil freezes some days along the year or not. Anyway for so weak structure most wouldn't go as deep as to forfeit entirely the expected (bad) effects of soil freeze, which for temperate zones is about 0.90 to 1.10 m deep (3 to 4 feet).
The layers composing your driveway also influence the top depth, but mainly on if you will end pushing away -to crack- your wall wen undergoing compaction. Many would build entirely the wall after making the paving layers themselves, or at least the exposed parts.
Respect surcharges many have been using for traffic from 400 kgf/m2 to 1000 kgf/m2. You may select any suitable one depending of the kind of vehicles you expect there.
Drilled piers (15 ft deep) sound as some luxury if you have reasonably strong soil. This is even more so for such secondary structures as this wall. Anyway, piling of a required depth would be considered where the soil is as bad that you want to put your wall entirely on a foundation that acts as a beam supported by the piles. This rarely will be the case for ordinary sites, but there are weak soils that may require these things if you want a long lasting structure. Even so for this case it is likely that the structure on piles might stay well but the soil continue separately moving and so some disgusting apparent dislocations appear with time.
Respect the slope it depends much on where it is placed, what goes above (in traffic) and of what material it is made. It is quite typical of public works where the apport material to build the sloped fill is mainly cohesionless and sound to go between 2:1 to 1.5:1 or so (H/V). There are circumnstances and fills that may require lesser slope. With very good fills and support at the base one may also go higher in slope. These things are analyzable, so if you think worth the effort, look for an able designer.
RE: A small interesting & practical retaining wall project to discuss
Where is the site? What are the soil conditions? Groundwater?
Give yourself as much distance away from the slope as possible. But if the slope is only 4 feet tall, then slope "failure" isn't that much of a risk -
Why are you considering the use of drilled piers? If you go with drilled piers, I'd design the system as a cantilever wall supported on drilled shafts, and forget the "footing".
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.
RE: A small interesting & practical retaining wall project to discuss
If a marking is needed a fencing as a non structural member will suffice.
Am I missing something?
RE: A small interesting & practical retaining wall project to discuss
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RE: A small interesting & practical retaining wall project to discuss
RE: A small interesting & practical retaining wall project to discuss
Where is the project located?
Please see FAQ731-376 by VPL for tips on how to make the best use of Eng-Tips Fora.