PSI - Issue 46

Ashikur Rahman Simon et al. / Procedia Structural Integrity 46 (2023) 162–168 Simon A. R. et al./ Structural Integrity Procedia 00 (2019) 000–000

167

6

Table 5. Storey stiffness (kip/in)

X - direction

Y - direction

Storey

Model 1 171.6 217.4 224.8 226.5 227.1 227.7 229.0 233.0 247.2 316.0 928.8

Model 2 428.4 871.4 1269.3 1639.9 2010.5 2416.9 2916.2 3617.4 4787.6 7550.3

Model 3 489.3 974.4 1414.0 1828.6 2247.8 2712.9 3290.9 4114.1 5518.0 8961.6

Model 4 793.7 1581.1 2296.5 2973.0 3658.7 4419.3 5361.0 6690.6 8919.7 14190.6

Model 5 465.0 929.4 1352.3 1753.0 2160.2 2613.4 3178.0 3983.0 5353.4 8692.8

Model 6 437.6 887.9 1294.3 1674.5 2056.2 2476.5 2994.9 3726.6 4954.6 7711.7

Model 1 209.1 292.7 314.0 321.2 324.9 328.1 332.9 343.4 373.2 491.4 1500.7

Model 2 229.7 463.3 668.0 852.2 1031.1 1223.7 1459.6 1794.6 2367.2 3742.9

Model 3 1410.2 2753.6 3937.8 5024.6 6095.9 7248.5 8624.0 10472.6 13352.6 18795.8

Model 4 381.9 757.7 1094.4 1406.4 1717.3 2058.7 2481.6 3085.5 4120.4 6606.9

Model 5 286.1 566.2 814.2 1041.5 1265.6 1509.8 1810.7 2239.1 2973.2 4751.6

Model 6 299.9 608.7 884.0 1137.9 1389.5 1665.0 2006.2 2495.2 3340.8 5411.5

Roof

Storey9 Storey8 Storey7 Storey6 Storey5 Storey4 Storey3 Storey2 Storey1

GF

19166.2 25043.4 36486.5 25231.8 22188.3

10793.7 44531.5 19526.5 14815.4 17598.4

3.5. Torsional irregularity Torsional irregularity in X and Y directions of all models is summarized in Table 6. According to BNBC, torsional irregularity exists when the ratio of maximum storey drift to the average of storey drifts in any direction is more than 1.2. If the values are more than 1 then we must take measures to reduce torsional force. In this study, no torsional irregularity is found in any model because of symmetrical building models. Table 6. Torsional irregularity 9th floor Model no. Direction ∆ 1 ∆ 2 ∆ max ∆ avg ∆ max /∆ avg Allowable limit Comment

X Y X Y X Y X Y X Y X Y

8.47 5.79 0.82 1.60 0.73 0.28 0.43 0.91 0.72 1.24 0.78 1.15

8.47 5.79 0.82 1.60 0.73 0.28 0.43 0.91 0.72 1.24 0.78 1.15

8.47 5.79 0.82 1.60 0.73 0.28 0.43 0.91 0.72 1.24 0.78 1.15

8.47 5.79 0.82 1.60 0.73 0.28 0.43 0.91 0.72 1.24 0.78 1.15

1 1 1 1 1 1 1 1 1 1 1 1

ok ok ok ok ok ok ok ok ok ok ok ok

1

2

3

1.2

4

5

6

3.6. Time period Time period of all the models is summarized in Table 8. It has been observed that the no shear wall model shows a maximum time period of 3.75 seconds among all the models. Time period for shear walls at center model is having a reduction of about 25%, the model with shear walls at sides and inner walls by about 73%, the model with shear walls at the periphery by about 70%, the model with shear walls at corners by about 65%, and shear walls at center and edges model by about 60%. After implementation of shear walls, time period is reduced significantly. It is because shear walls give high stiffness to the structure that can reduce the time period of structure. It is also observed that shear walls at periphery model and shear walls at sides and inner walls model show relatively low natural time period compared to others.