toe/heel proportions
toe/heel proportions
(OP)
I have a wall with a property line so close to the face of the wall that it isn't funny. is there any reason I cannot use a retaining wall without a toe if I can meet all of the soil pressure and stability requirements? I cannot think of one...but then...
thanks.
thanks.





RE: toe/heel proportions
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora.
RE: toe/heel proportions
One approach to retaining walls on property lines is to tie them back (install tiebacks or anchors into the backfill to restrain the wall).
Another approach is to use a Mechanically Stabilized Earth (MSE) wall built out of internal reinforcement that acts like a gravity wall and gets its stability out of its own weight.
Another approach is to use a cantilever wall that gets stability from internal bending moment capacity and is "anchored" by the underlying soils.
I hope this helps.
Glen
RE: toe/heel proportions
thanks for thre input.
RE: toe/heel proportions
I have placed a segmental retaining wall 25 mm from a property line, with a toe load. Depending on the type of wall (or blocks) you are using, a vertical wall near the property line with toe load can be used, followed by a batter (if required).
Check out the segmental retaining wall blocks by risistone.com., many be the Durahold II blocks will work, they did for me along a property line with some truck traffic.
regards
RE: toe/heel proportions
I've done far more conventional walls, but it's pretty clear to me that MSE is the way to go on "short" walls where the underlying support quality is good to excellent.
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora.
RE: toe/heel proportions
What is the finished height of your proposed wall? The height can greatly influence the type of wall needed. Are you placing fill behind the wall, above original grade, to create a new higher finished grade? I would not worry about tiebacks, tie rods, geogrids, etc., until I knew the wall height, soil conditions, required surcharge loads, and if this is a fill wall or a cut wall. Fire lane loading should still meet HS20 or HS25 loading, shouldn't it? You need to consider more than the location of the property line when picking wall type.
gandersen,
you make good points. By "cantilever" wall, did you mean a cantilevered soldier beams/sheet pile wall?.
RE: toe/heel proportions
RE: toe/heel proportions
Your wall isn't very high. You may be able to install a soldier beam wall with either precast concrete lagging or precast panels. These can have an architectural finish. Drilling rock for soldier beam embedment below finished grade could be expensive. Check AASHTO specifications for highway bridges. The manual contains pressure envelopes for cantilevered soldier beam and sheet pile walls.
Your best wall choice could be a segmental retaining wall made of blocks with geogrid, probably founded on rock. This would require a temporary, shallow, sloped excavation onto the adjacent property. It just wouldn't make much sense to install sheeting along the other property line in order to maintain it while making a 2 to 4 feet deep wall excavation. If you have to sheet the excavation, you might as well build a cantilevered soldier beam wall.
RE: toe/heel proportions
You still have several options of retaining walls based on discription. But, from what I read, it may be best to use a cast-in-place wall anchored to bedrock with tie backs also anchored to rock. With the rock only 2 - 4 ft below grade, this is not a problem or big cost to excavate.
I would assess the cost of a few options, including maintenance costs and potential cost associated with damage to the wall should this occur. Also see if there is a preference by the owner. I mention this becasue the SRW mentioned before came about due to construction costs and potential long term maintenance costs. And on another project, the opposite occurred.
regards
RE: toe/heel proportions
RE: toe/heel proportions
I was faced with a virtually identical situation about two years ago. In this case there was a [three] tiered Keystone block wall located just inside the property line. The wall not only provided the "edge" to a site but it also "retained" a buried circular metal detention tank. In addition, the local [County] agency required a fire truck loading immediately along the top of the wall.
The wall reinforcement was installed per design, in itself a somewhat unusual event, but the backfill was a relatively poor quality silty sand wiht "junk", although it was reasonably well compacted in-place.
The contractor built the wall before installing the detention tank. Then, because he wasn't paying attention, he dumped his trackhoe through the top of the tank. This required the removal and replacement of the tank. This replacement process resulted in loaded and unloaded dump truck traffic along the top of the block wall. In all, we counted a total of three thousand four hundred passages of trucks, many of them "overfilled" since they did not have to use a public street. This traffic resulted in about an inch of movement in only the top blocks. Based on this experience I will firmly recommend the use of a geogrid reinforced Keystone [standartd] block wall to you for this project. Providing you engineer the wall appropriately, and closely observe the construction process you should be fine.
Best of luck
g7mann
RE: toe/heel proportions