*A. Comparative study of building on soil class-A*

*a) Comparison of Story bending Moment*

The static stiffness of soil has influenced the bending moments, which for the fixed-base and the Flexible-base cases are given below for column and for beam respectively. when comparing the average Story Bending Moment of structural system in both beam and column there is a significant increase for the fixed base with SSI depth of 1.0m for the value of 22.64% less than in column and 9.97% in beam.

This is because of soil flexibility influences internal stress distribution on the frames. But for the increased SSI depth, there is increased static stiffness, there is a decrease in bending moment, when comparing 1.0m embedment with 3.0m embedment 11.01% decrease of moment in column and 8.31% decreased moment in beam, again comparing 3.0m embedment with 5.0m 15.53% decrease of moment in column and 10.57% increase in beam.

*b) Comparison of Story shear force*

To study the effect of SSI depth variation, the column shear force comparison only is considered. The shear force diagram of the column shows that there is a significant increment of about 3.53% from fixed base to 1.0m SSI depth. For further increment of SSI depth as compared with 1.0m depth there is about averagely 9.97% reduced in 3.0m and 7.05% reduction in 5.0m depth of SSI. Graphically those cases of average shear in both structural systems for different SSI depths.

*c) Comparison of Floor Displacement*

The floor displacement obtained from the fixed base structural system differs significantly from the flexible one. For the structural system the variation of 1.05% increment is observed from fixed to 1.0m and 5.47% decreased when 3.0m embedded, 3.78% increased again in 5.0m embedded

*B. Comparative study of Building on soil class-C*

*a) Comparison of Story bending Moment*

For the purpose of comparative study to know the influence of embedment depth on the two extreme soil case soil classes, soil class-C is again taken in to study. The bending moment is influenced by varying the SSI depth of structures. When taking in to consideration flexibility of 1.0m SSI depth with fixed base there is increment of averagely about 14.53% in column and 5.65% in beam, then increasing the SSI depth to 3.0m and comparing with 1.0m SSI depth there is reduction of 4.07% in column and 4.65% in beam is observed and this number is again reduced to 3.11% in column and 0.94% in beam, when increasing the SSI depth to 5.0m. the chart below describes graphically the influence of SSI depth on soil class-C.

*b) Comparison of Story Shear Force*

the shear force difference is observed from the analysis output in column. The flexible base Story shear force is increased averagely to about 3.54% than 1.0m SSI depth and again the variation is changed when comparing 1.0m of SSI depth of 3.0m and it is reduced to the 5.04%, it becomes to 3.13% decreased.

*c) Comparison of Floor Displacement*

When comparing the floor displacement observed in analysis output, there is about averagely 4.61% of increment from fixed base than for flexible one, and when comparing 1.0m SSI depth with 3.0m it shows that 4.80% averagely reduced floor displacement and when considering the 5.0m embedment depth the floor displacement is reduced insignificantly to 0.60%.