Retaining Wall Connection To Rock/Ledge
Retaining Wall Connection To Rock/Ledge
(OP)
I am designing a retaining wall that will sit on ledge. I have completed a full analysis and have a final design that requires a 5 foot heel in order to add enough friction force to prevent sliding. Has anyone ever doweled a footing to ledge to prevent lateral movement? If so, what values could I conservatively assume for the ledge such as allowable lateral bearing pressure from the dowels to the ledge? Any info would be greatly appreciated.






RE: Retaining Wall Connection To Rock/Ledge
If I understand correctly, you will grout rebar dowels into the rock and then pour your retaining wall heel around the dowels. The shear transfer will be limited by a) the shear strength of concrete, b) the shear strength of the rock, or c) the shear strength of the dowel/grout. You should check all three (with appropriate safety factors).
Alternately, you could use a shear key into the rock and avoid doweling altogether.
I would perform unconfined compressive strength tests on any rock cores in order to estimate the rock shear strength. Additionally, you could use the RQD from the rock cores to put together approximate Rock Class or RMR values to develop a design shear strength of the rock.
Good Luck.
Jeff
Jeffrey T. Donville, PE
TTL Associates, Inc.
www.ttlassoc.com
The views or opinions expressed by me are my own and do not necessarily reflect the views or opinions of my employer.
RE: Retaining Wall Connection To Rock/Ledge
RE: Retaining Wall Connection To Rock/Ledge
RE: Retaining Wall Connection To Rock/Ledge
5 foot heel doesn't seem like too much unless it is a difficult excavation.
Rock anchor depth will depend on the characteristics of the rock. You might want to extend as deep as the all is tall in order to engage soil weight equal to the DL you were going to need in the first scenario.