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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SI-10, a reduction in stiffness by 43% and 84% has increased the displacement response by 9% and 71.7% respectively when compared to the regular one. The abrupt change in the displacement response along the height of the building at the location of irregularity is also to be noted. It is also observed for most of the SI cases that reduction in storey stiffness increases the storey drift. The same is found to be the maximum at the location of irregularity. The cases SI-2 and SI-10 have shown maximum storey drift compared to the remaining cases of SI. According to IS 1893:2016 (Part 1), the drift should not exceed 0.004 times the storey height. Thus SI-2 and SI-10 have exceeded the specified drift limits. Figure 4 shows the displacement responses and storey drift of VGI cases. Increase in maximum displacement response is observed for VGI-4, VGI-5, VGI-6 and VGI-8 by 79%, 15%, 76% and 50% respectively than that of regular one. The displacement response is reduced by 20%, 22%, 26%, 26%, 22% and 41% for VGI-1, VGI-2, VGI 3, VGI-7, VGI-9 andVGI-10 respectively. The results show that the displacement response is increasing along the height of the building irrespective to the presence of setback. In all the cases, sudden increase in the drift value is observed at the areas of discontinuity in geometry. For VGI-1 due to sudden change in vertical configuration at the 7th storey, drift at that particular storey has increased abruptly and then decreased. Other cases have also followed the same pattern. Among the VGI cases, VGI-6 and VGI-9 are found to display maximum displacement and storey drift.

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Displacement(mm)

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VGI-1 VGI-5 VGI-9

VGI-2 VGI-6 VGI-10

VGI-3 VGI-7

VGI-4 VGI-8

VGI-4 VGI-8

VGI-10

Fig.4. Displacement response and storey drift for VGI cases.

Figure 5 represents the displacement response and storey drift of REC and TI cases. For all the cases of REC, the displacement response and storey drift are found to be less when compared to the regular one owing to the reduction in mass and stiffness. It is observed that the configuration with the least plan area has less displacement response and storey drift and vice versa. Out of the seven cases of REC, REC-4 has more plan area and shows higher response compared to the other cases. The amount of torsion induced in TI-1, TI-2 and TI-3 are 1.56, 1.43 and 1.42 respectively. It is observed that for the cases of TI-2 and TI-3 REC irregularities, torsion is within the limits (i.e. TI < 1.5). Due to the increased stiffness, all the TI cases have shown lesser displacement response and storey drift than the regular model. Due to the presence of columns having different cross-sectional area, TI-1 has shown a decrease in response by 37%. TI-2 has shown a reduction in response by 77% owing to the presence of two shear walls at the corner. TI-3 has two shear walls and two different cross sectional areas of columns and it behaves similar to regular