PSI - Issue 14

Siva Naveen E et al. / Procedia Structural Integrity 14 (2019) 806–819 Siva Naveen E, Nimmy Mariam Abraham, Anitha Kumari S D / Structural Integrity Procedia 00 (2018) 000–000

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respect to the regular model. Due to the sudden change in the vertical geometry at the 6 th storey level, all the three cases of CoI-5 are showing abrupt changes in the drift response. It is observed that all the three cases of CoI-6 show higher displacement and drift than that of regular model. Out of three cases, C-16 has shown more displacement response and the increase is 85% with respect to the regular model. Due to the presence of SI at the first floor, the drift is maximum at the first storey level. All the three cases have shown considerable effect on the storey drift and has exceeded the limits specified as per IS 1893:2016(Part-1). C-18 has shown lesser response because of the reduction in mass and stiffness of the columns at the higher levels (storey 6 to storey 9) and increased stiffness of the frame due to the presence of shear wall. Displacement response of C-18 has reduced to 85%. C-19 and C-20 have shown higher response compared to regular model. Out of three cases, C-20 has the higher displacement response and the percentage increase in displacement response with respect to regular model is 47%. Maximum drift is also shown by C-20.

1 2 3 4 5 6 7 8 9

0 1 2 3 4 5 6 7 8 9

Level

Level

0

10

20

30

40

0

5

10

15

Displacement(mm)

Storey Drift(mm)

R

C-1 C-5 C-9

C-2 C-6

C-3 C-7

R

C-1 C-5 C-9

C-2 C-6

C-3 C-7

C-4 C-8

C-4 C-8

C-10

C-11

C-10

C-11

Fig.6. Displacement responses and storey drift for CoI cases (C1-C11).

Increase in maximum displacement for the configurations that have shown the highest response from each type of single irregularity is summarized in Table 5. It is seen that VGI is the most critical irregularity among the single irregularities considered in this study. Table 6 gives the percentage increase in displacement response for all the combination of irregularity cases with respect to the regular case. Out of the seven combinations (20 different cases), the combination of stiffness and vertical geometric irregularities (C-8) has shown maximum displacement response followed by the combination of mass, stiffness and vertical geometric irregularities (C-11). The combination cases having re-entrant corner and vertical geometric irregularities (CoI-5: C-12, C-13 and C-14) have shown less displacement response. It is further seen that the response shown by the frames having combinations of all five irregularities is less compared to that of the frames having combination of three irregularities. This reduction in response is due to the presence of shear wall and reduction in mass and stiffness in the configuration. It is observed from Tables 5 and 6 that certain cases involving combination of irregularities are way more critical than the ones involving single irregularity. It is also observed that the response displayed by few configurations involving combination of irregularities is less than that of the regular one. The maximum base shear and overturning moment for all the cases studied are tabulated in Table 7. Among the cases having single irregularity, MI cases have shown higher base shear and overturning moment than all other