Project 1_Comparative study of different storey buildings for Seismic forces
COMPARATIVE STUDY OF DIFFERENT STOREY BUILDINGS FOR SEISMIC FORCES
AIM
To model and analyze different buildings with varying parameters to study the influence of those parameters on building
Characteristics by comparing the models
PROCEDURE
The following table shows the building with different parameters
From the analysis of models following comparisons are made
EFFECT OF STIFFNESS ON T
Compare fundamental natural periods of buildings E and F as well as G and H.
Why is there a marginal or significant difference in the fundamental natural periods?
The following pictures show the comparison of E, F, G, and H
MODEL E
MODEL F
MODEL G
MODEL H
If we compare the period of E and F, we can see that the period of F is more than E because, model F has uniformly sized columns throughout the building, whereas the size of columns is decreasing with height in E and the uniformity of columns contribute to the stiffness of building which in turn increases the period
The same concept applies for G and H where the period of H is more
EFFECT OF MASS ON T
- Compare fundamental natural periods of building H, J, and K
BUILDING H
BUILDING K
BUILDING J
The period of H is higher than J which in turn is higher than K
It happens due to variations in masses
EFFECT OF BUILDING HEIGHT ON T:
- How do the fundamental natural periods of buildings A, B, F, and H
- Change with change in building height?
BUILDING A
BUILDING B
BUILDING F
BUILDING H
We can see there is a considerable increase in the period of the building due to an increase in the. of stories
Hence increase in height increases the stiffness of the building
EFFECT OF COLUMN ORIENTATION ON T
- How do the fundamental natural periods of buildings B, C, and D change with change in column orientations?
BUILDING B
BUILDING C
BUILDING D
Time period of C is more than D which in turn is more than B
Therefore stiffness of the building is more if the columns are oriented along their longer length direction
EFFECT OF FLEXURAL STIFFNESS OF STRUCTURAL ELEMENTS ON MODE SHAPES
- Compare fundamental mode shape of building B in two situations when flexural stiffness of Beam relative to that of adjoining columns is very small versus when it is large
When flexural stiffness of the beam is smaller than adjoining columns
MODE 1
MODE 2
MODE 3
When the flexural stiffness of beams is larger than adjoining columns
MODE 1
MODE 2
MODE 3
ALL MODES
- EFFECT OF AXIAL STIFFNESS OF VERTICAL MEMBERS ON MODE SHAPES
- Compare fundamental mode shape of building H in two situations when the axial cross-sectional area of columns is very small versus when it is large
When axial cross-sectional area of columns is very large
MODE 1
MODE 2
MODE 3
ALL MODES
When the axial cross-sectional area of the column is very small
MODE 1
MODE 2
MODE 3
ALL MODES
- EFFECT OF DEGREE OF FIXITY AT COLUMN BASED IN MODE SHAPE
- Compare the fundamental mode shape of Building B in two situations when the base of the column is pinned versus when it is fixed
When the supports are pinned
MODE 1
MODE 2
MODE 3
ALL MODES
- EFFECT OF DEGREE OF FIXITY AT COLUMN BASES IN MEDE SHAPE
- Compare fundamental mode shape of building B in two situations when the base of the column is pinned versus when it is fixed
When supports are fixed
MODE 1
MODE 2
MODE 3
ALL MODES
