retaining wall = ada switchback ramp

huangyhg

retaining wall + ada switchback ramp
i started this another thread but a friend thought it belonged more over here. hopefully i can continue the great help i've been getting.
other thread:
if the retaining wall is to extend up past the ramp slab to form the railing, then the ramp slab is just an inclined sidewalk and the retaining wall needs to be designed for the surcharge and the lateral load required by code due to the handrail (usually 50 lb/ft or 200 lb concentrated).  if the retaining wall does not extend up past the ramp slab, then i would expect to see the slab overhang the retaining wall a couple of inches.  retaining wall is sloped to match ramp slope, fill is compacted well, ramp is placed on top of fill and extends over top of retainig wall.  we usually thicken the slab over the retaining wall to 6" or 8".  guard rail and hand rail is attached to ramp slab.
i envisioned the retaing wall matching top elevation or exstending by a couple of inches.(being rectangular) then having the ramp start from elev. 15' to 12' 8" (five foot landing), then ramp from 12'8" to 10'4" (five foot landing) then ramp from 10'4" to existing 9'. then on both sides have gravity walls coming down triangular shaped to meet elev. 15' to 9'.
is that sounding about right?
thanks twinnell. you sparked a good idea.
and thanks to the rest of you for ideas.
~rich~