Common Rules of Thumb for Residential Rough Grading? 1

[raydefan]

I have started to work on some rough grading plans for residential subdivisions and person I am working under is not very precise in his methodology. For example, sometimes he will put a two foot bench at the top of slope between back to back pads, and sometimes he won't with to definite reason for each. I am looking for some rules of thumb, so when I need to teach someone I can be definite on why I do something. Here are the "rules" I'm looking for:

1. Bench width for top of slope for back to back pads? Is there a difference in pad elevation (>1' obviously) where this bench can be reduced or eliminated?

2. Bench width for top of slope for side to side pads?

3. Maximum retaining wall height in back of lot? Is this height from top of wall to top of footing?

4. When do you put v-ditch behind a retaining wall?

Any help on these rules would be appreciated. Also, does anyone know of any good books on this subject?

Thanks,

Jeff

 

[francesca]

You're looking for a short cut here. You don't need rules of thumb, you need understanding of why these things are being done.

 

[raydefan]

francesca,

Thanks for your reply, but I do understand, for the most part, why things are done. However, a lot of these "rules" are subjective. For example, I believe the benches at the the tops of slopes are there so that a wall can be built between the two lots. However, I've had contractors tell me they need two feet and I've had contractors tell me they need one foot to properly build the wall. I'm looking for a consensous on what is the standard for each of these questions.

Jeff

 

[cvg]

for good constructability and future maintenance I would suggest at least 2 feet on each side of the wall plus the width of the wall / footing. Total of nearly 5 feet for a good bench. Anything less will make things more difficult.