Shear wall for basement of residential building in sap2000? 1

[sagunconsult]

My problem is very simple. Generally my buildings have following dimensions.

Building type: RCC Basement + 5 storied.
General column size used 14" x 14" at perimeter and 16" x 16" and some time 18" x 18" at internal.
Concrete used M25 in column and M20 in beam and slab
Re-bar used are TMT fe500 (combination of 16mm and 20mm and 8mm for stirrups)
foundation isolated and eccentric with bearing capacity 200 kn/m2
height of basement is 10' (out of which 8' concrete wall is surrounded by back-fill soil} i.e. 2' share wall is exposed above ground
shear wall thickness is 6" with two layer of reinforcement, wall braced in all side with column and beams)
depth of foundation 6' deep from basement (for isolated footing)

questions:
should i really consider these share wall in analysis? its only 8' of lateral earth pressure?
share wall also take part in sharing vertical load along with column? which reduced the % of reinforcement in column at basement.
when i model lift shaft (rcc) the results are very much different (reinforcement in surrounding columns (around rcc lift) are reduced to minimum requirements 0.8% ). its only basement+5 storied, can i go for brick for shaft wall?
Am i missing something or i am ignoring elephant in this matter? not sure what am i supposed to do.

Please drop your any comments and suggestion regarding this and any related matters. even discussion will help me and lots of people.

 

[structSU10]

What is your LFRS for the upper floors? Is the earth pressure balanced on all sides of the building?

 

[sagunconsult]

its RCC moment resisting frame, and yes the earth pressure is balanced on all side of the building. it is excavated on plane ground with no GWT problem, soil is gravel mix silty. I have attached my sap2000 v14.0.2 *.sk2 and *.sdb file as well. Its just normal rcc building structure. (note a size of about 6' x 6' hole is left for lift provision. but i still not sure if i should model concrete share wall for lift shaft or what. Please have a look and point where ever its wrong and any improvement i can make. the load combination is as per my country standard (Nepal Building Code). If you can provide us some typical building analysis files that will be very much helpful for reference .

http://files.engineering.com/getfil...-4fb2-a918-4a96af884a36&file=SAGUNCONSULT.SDB

 

[sagunconsult]

s2k file

 

[hokie66]

Not much help with your SAP results, but I am just wondering how you would cast a 6" basement wall with two layers of reinforcement. How do you compact the concrete?

I wouldn't think of using a brick lift shaft in a RC building. And I wouldn't use less than 1% steel in the columns. Your program is telling you that the lift shaft is acting as a shear wall, and you need to reinforce it as such. Pay special attention to the wall with door penetrations.

 

[sagunconsult]

@hokie66
Yes you are right minimum thickness is 8" for double reinforcement, i was wrong here. . I also don't use minimum % of steel in column. In other had shear wall is at basement only so i guess its not problem, is it? Actually i don't consider share wall at basement level for analysis and only provide minimum reinforcement as code provision.
But i don't want to ignore about this for lift shaft. If Any tips?