Hi all,
I will be thankful if you can answer my question and give guidance in this regard.
we are designing a raft foundation using staad pro SS6.
we are assuming
1. We are designing this foundation for 25 mm settlement and bearing capacity is 200kN/m2.
2. We are using IS 456:2000 code for this concrete design.
3.Modulus of subgrade reaction as (200kn/m2)/0.025=10000Kn/m2/m.
4. we are considering elastic mat support direct y only subgrade 10000kn/m3 for all node points.
5. Now for the points below the column, we are taking support reactions are (10000*influence area of that column )=(10000*0.4*0.4*4)=6400Kn/m2/m and on those points supports specifications we are providing as
"FIXED BUT MX MZ KFY 6400 "to transfer this column load to the foundation.
5. We are eliminating that portion (influence area below the column)in case of design.
my questions are
1 Is it okay if we providing this supports specifications below the column influence area points?
2. For which value of settlement we shall consider this, if modules of subgrade reaction test is not performed on site.
should we consider immediate settlement value or just take 25mm settlement value?
3. While generating the plate stress contour we have seen that below the column influence are zone we don't get any stress value is it okay or not?