Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
(OP)
Hello,
I'm doing some research...
A client wishes to add to the retained height of an existing masonry retaining wall. The wall is approximately 6' high and is built with reinforced solid-grouted 8" cmu. They wish to add about 24" to the top of the wall.
I'm considering different things to do...and was wondering what you all have done. What do you think is the most efficient way to increase the retained height? The following are some of the things I'm considering:
--Add geo-fabric to the wall to reduce the bending span in the wall. Likely no footing change needed here.
--Add masonry buttresses on the inside of the wall to help the masonry. Expand the footing as needed.
--Add a new wall in front of the existing wall to relieve the pressure increase. Expand the footing...or add tie backs.
Thanks in advance for your help!
I'm doing some research...
A client wishes to add to the retained height of an existing masonry retaining wall. The wall is approximately 6' high and is built with reinforced solid-grouted 8" cmu. They wish to add about 24" to the top of the wall.
I'm considering different things to do...and was wondering what you all have done. What do you think is the most efficient way to increase the retained height? The following are some of the things I'm considering:
--Add geo-fabric to the wall to reduce the bending span in the wall. Likely no footing change needed here.
--Add masonry buttresses on the inside of the wall to help the masonry. Expand the footing as needed.
--Add a new wall in front of the existing wall to relieve the pressure increase. Expand the footing...or add tie backs.
Thanks in advance for your help!





RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
Thanks for the response.
Any particular type of geogrid or geotextile?
Thanks.
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
http://en.wikipedia.org/wiki/Geosynthetics
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
Thanks for the help.
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
DaveAtkins
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
http://www.eng-tips.com/viewthread.cfm?qid=374325
Unless of course you plan on removing and re-installing the original backfill with added geogrid in it. That would reduce the load on the original wall.
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
I plan to:
--Remove the retained soil
--Install geogrid at intervals...</=36" o.c...about 12" above the top of the existing footing...and about 24" below the top of the wall.
The wall is reinforced one way...vertically. So the geogrid reduces the bending moment and shear forces in the existing wall. Instead of a 8' cantilever...we have a masonry wall that is supported every 36" o.c. This seems like a good, safe route to take for this type of alteration.
Having thought this through a bit...I'm not sure there's much else that can be done...that is more efficient.?
It's good to hear and learn what others are doing and recommend...thanks!
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
I would proceed with caution.
The mechanism you are describing does not consider strain compatibility.
Your nearly rigid retaining wall is far more sensitive to lateral movement as compared to the mobilized stiffness of your geogrid-soil system.
If you have a flexible wall, like an MSE wall, geogrid works perfectly. Not for a nearly rigid cantilever wall.
Your wall will "feel" the load via lateral active movement before your grid is even 50% mobilized.
You are better off using low strength grout or geofoam (other cautions to be considered) than geogrid unless you can accept large wall rotations.
Good luck.
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall
RE: Cantilevered Retaining Wall: Adding to the Retained Height in an Existing Wall