Typical EFP?
Typical EFP?
(OP)
What are some "typical" values that get used for EFP?
I'm asking because I've been doing some work on a few reinforced concrete retaining walls recently. My supervisors pass off the important information and I go to work. With geotech and loading info in hand I try to keep sizes for my walls in general dimensions (all references I have say pretty much the same but looking specifically from Bowles "Foundation Analysis and Design" chapter 12-2 page 433... just so you know where I'm coming from). I have a hard time coming up with these dimensions and my supervisors are always suprised at how thick my walls are, how long my footings are for sliding (they would prefer that I didn't use keys), and how much rebar I have. After doing a little searching around it seems to me that the EFP that I get off the geotech report (60pcf for clay/silty) is a fairly high number in the spectrum of soils, which might be why (I'm hoping) that my layouts end up so large. Any thoughts?
I'm asking because I've been doing some work on a few reinforced concrete retaining walls recently. My supervisors pass off the important information and I go to work. With geotech and loading info in hand I try to keep sizes for my walls in general dimensions (all references I have say pretty much the same but looking specifically from Bowles "Foundation Analysis and Design" chapter 12-2 page 433... just so you know where I'm coming from). I have a hard time coming up with these dimensions and my supervisors are always suprised at how thick my walls are, how long my footings are for sliding (they would prefer that I didn't use keys), and how much rebar I have. After doing a little searching around it seems to me that the EFP that I get off the geotech report (60pcf for clay/silty) is a fairly high number in the spectrum of soils, which might be why (I'm hoping) that my layouts end up so large. Any thoughts?





RE: Typical EFP?
RE: Typical EFP?
RE: Typical EFP?
Now the question is whether you want to design your wall to rotate 1 inch in 10 ft or not. Also, what backfill can you truely depend on, and will the slopes at the top and the toe be horizontal.
Good luck.
f-d
¡papá gordo ain't no madre flaca!
RE: Typical EFP?
Sorry for any confusion.
f-d
¡papá gordo ain't no madre flaca!
RE: Typical EFP?
RE: Typical EFP?
Thats a good idea, I checked the state's typical drawings and they are for 27pcf EFP, but are fairly smaller in size.
fattdad,
I'm making the assumption that at-rest vs active conditions means the same as non-yielding vs yielding walls. The "Conclustions and Recommendations" in the geotech report are 90pcf and 60pcf for non-yielding and yielding walls respectively. I am not given a friction angle so I was back calculating to obtain that of 19.48 deg (I think thats OK, I've seen it done before). The deflection of the wall will not be a problem.
BigH,
I don't have enough info from the geotech report to be able to do Coloumb or Rankine. Otherwise I agree and would feel a little more confident where I have been taught them in school and have a better understanding of them.
RE: Typical EFP?
RE: Typical EFP?
RE: Typical EFP?
RE: Typical EFP?
Not AASHTO, just some wall out in amongst the grass.
civilperson,
Bingo. Good reference, I had no idea that was there. We only had the 1992 edition but our numbers were pretty close. Thanks.
DRC1,
The numbers seemed high to me too after doing a little digging around. I will suggest that it might be worth to do a little poking around and see if we can use any smaller number with proper detailing. I would imagine that it would help significantly if we could.
RE: Typical EFP?
Then again, the friction angle may not be 30 degrees.
f-d
¡papá gordo ain't no madre flaca!
RE: Typical EFP?
RE: Typical EFP?
RE: Typical EFP?
RE: Typical EFP?
Good luck.
f-d
¡papá gordo ain't no madre flaca!
RE: Typical EFP?
Another thought;
Are the clays expansive?
If so, the efp will be increased more toward ko to reflect the creep of the clay.
RE: Typical EFP?
RE: Typical EFP?
RE: Typical EFP?
RE: Typical EFP?
RE: Typical EFP?
f-d
¡papá gordo ain't no madre flaca!