Is there a prescriptive method that talks about wall reinforcement at stairwells? I am looking everywhere and cannot find anything... Do i need to hire an engineer for a basement? drawing

Since the wall is unsupported it does need to be treated the same as a retaining wall. As well the footing should be wider in this area and more towards the inside of the basement area.

But your question always leads to more.

the staricase - is it cast in place? or wood?

In theory the rebar should be placed to the outside (dirt side) =, now with the span being less then 12' (I assume) it is a minor load going against the wall and you could probably get away with following the rest of the wall.

Now that I have confused you. for the little bit it is, chances are the inspector will not notice or say anything, keep the norm, but be sure to terminate the top of the wall with 2 bars horozontal

Chris,

I am with you on all the points... and i do have a retaining wall chart/diagram that gives rebar for different hights and wall thicknesses and even covers the footing size and reinf...

I actually got the answer from PCA tech support guy. 2 answers actually... but none of them are prescriptive... it is amazing the codes and prescriptive guides are silent on this...
1. treat the 12' opening as a 12' high wall - the horizontal rebar becomes vertical rebar (which you look up for a 12' high wall)... the sides of the opening will have to be treated as pilasters (you could place in a little vertical cage on either side. I would not recommend creating a pilaster but just put a few extra bars in there...

2. make the top of the wall a flat down bond beam (icfs are usually 12 to 13" wide anyway) and reinfrce it with a rebar cage to simalte a top restraint...

Normal rebar placement as per the perscriptive method should suffice. If you read the design requirements, if you are under 12' of missing floor then no special rebar requirement is needed. The rebar always goes on the inside of the wall. This is the side under tension as I learned from the Nudura, Amvic and Arxx training classes.

Hey Smartwall... Awesome! Where do you see the 12' number? any documents?

Well, hey, we can't have this too easy or I'd be out of a job.
Too many variables to make a "simple" table, but look in ACI 332, Residential Concrete. It gives a lot of tables you're asking for. These are ones you won't see elsewhere.
The "no design with unsupported less than 12 feet" is a rule-of-thumb, and should be used sparingly.

Under General section 1.0. It describes the limitations of icf's. Plus in looking at your drawing, your only dealing with a total wall lenght of 15' not 65'. The corner turns add strength to the wall.

Jerry,
I just looked in aci332-04 and cound not find this anywhere... i know its a rule of thumb but it must have come from somewhere...

Smartwall,
which document are you referring to? Where did the 65 number come from... lol a bit puzzled... i know about the corners...

I was refering to the fact that you were dealing with a relatively short wall section not a straight wall of 65' in length which makes all the difference in the world as far as backfill load. The document is the precriptive method in the begining it states the limitation of it's design, like not using icf's for walls that are not perpendicular to the ground.

ACI 332-10 Differs greatly from the earlier versions. Tables and everything. It really answers a lot of questions. Check it out if you can get one.

Hey Jerry - i just purchased the 2010 version - they are almost identical... oh well...

smartwall.... i still cant find it in the general section for ICFs in the IRC...

SECTION R611
EXTERIOR CONCRETE
WALL CONSTRUCTION
R611.1 General. Exterior concretewalls shall be designed and
constructed in accordance with the provisions of this section or
in accordance with the provisions of PCA 100 or ACI 318.
When PCA 100, ACI 318 or the provisions of this section are
used to design concrete walls, project drawings, typical details
and specifications are not required to bear the seal of the architect
or engineer responsible for design, unless otherwise
required by the state law of the jurisdiction having authority.
R611.1.1 Interior construction. These provisions are
based on the assumption that interior walls and partitions,
both load-bearing and nonload-bearing, floors and
roof/ceiling assemblies are constructed of light-framed construction
complying with the limitations of this code and the
additional limitations of Section R611.2. Design and construction
of light-framed assemblies shall be in accordance
with the applicable provisions of this code. Where second-
story exterior walls are of light-framed construction,
they shall be designed and constructed as required by this
code.
Aspects of concrete construction not specifically
addressed by this code, including interior concrete walls,
shall comply with ACI 318.
R611.1.2 Other concrete walls. Exterior concrete walls
constructed in accordance with this code shall comply with
the shapes and minimum concrete cross-sectional dimensions
of Table R611.3. Other types of forming systems
resulting in concrete walls not in compliance with this section
shall be designed in accordance with ACI 318.
R611.2 Applicability limits. The provisions of this section
shall apply to the construction of exterior concrete walls for
buildings not greater than 60 feet (18 288 mm) in plan dimensions,
floors with clear spans not greater than 32 feet (9754
mm) and roofs with clear spans not greater than 40 feet (12 192
mm). Buildings shall not exceed 35 feet (10 668 mm) in mean
roof height or two stories in height above-grade. Floor/ceiling
dead loads shall not exceed 10 pounds per square foot (479 Pa),
roof/ceiling dead loads shall not exceed 15 pounds per square
foot (718 Pa) and attic live loads shall not exceed 20 pounds per
square foot (958 Pa). Roof overhangs shall not exceed 2 feet
(610 mm) of horizontal projection beyond the exteriorwall and
the dead load of the overhangs shall not exceed 8 pounds per
square foot (383 Pa).
Walls constructed in accordance with the provisions of this
section shall be limited to buildings subjected to a maximum
design wind speed of 130 miles per hour (58 m/s) Exposure B,
110 miles per hour (49 m/s) Exposure Cand 100 miles per hour
(45 m/s) Exposure D.Walls constructed in accordance with the
provisions of this section shall be limited to detached one- and
two-family dwellings and townhouses assigned to Seismic
Design Category A or B, and detached one- and two-family
dwellings assigned to Seismic Design Category C.

My appologies for that. But the tables apply to ICF, also. For flatwall ICF, there are no design differences, so you won't find anything specific to ICF.