Issue 54

F. Brandão et alii, Frattura ed Integrità Strutturale, 54 (2020) 66-87; DOI: 10.3221/IGF-ESIS.54.05

Looking Tab. 3 it is important to note to the Loma Prieta Earthquake the ISD of story numbers 2, 3, 5, 6 and 7 exceed ISD limit . To the L’Aquila Earthquake and Canterbury Earthquake the story numbers 2, 3, 4, and 5 exceed ISD limit . And to the Non-Stationary Artificial Earthquake, the non-stationary artificial earthquake which could generate resonance of structure, only the story number 10 did not exceed ISD limit . Therefore, this building requires a vibration control system in order to reduce the interstory drift to the imposed limits. Thus, in Scenario 1 a vibration control using a single TMD of mass m d =6715 kg installed at the top floor of the building, at node 63, was proposed. The parameters ( k TMD and C TMD ) were optimized through the optimization problem shown in Eq. 11. In the WOA the number of search agents and interactions were defined in 50 and 100, respectively. The convergence curve of this problem is presented in Fig. 8 which resulted in optimal values for spring and damping constants corresponding to k TMD =1513880 N/m and c TMD =32878 N.s/m and the TMD frequency of f TMD = 2.3897 Hz . The results obtained for this scenario are reported in Tab. 4 and the percentage of reduction of D max and ISD regarding the uncontrolled structure is shown in Tab. 5.

Figure 8: Convergence curve of Scenario 1.

Scenario 1- Response to single TMD at the top floor

Non-Stationary Artificial Earthquake

Loma Prieta Earthquake

L’Aquila Earthquake

Canterbury Earthquake

Story number

ISD limit (m)

D max (m)

ISD (m)

D max (m)

ISD (m)

D max (m)

ISD (m)

D max (m)

ISD (m)

1

0.0091

0.0030

0.0030

0.0025

0.0025

0.0036

0.0036

0.0039

0.0039

2

0.0137

0.0126

0.0096

0.0111

0.0086

0.0152

0.0117

0.0166

0.0127

3

0.0099

0.0177

0.0051

0.0161

0.0050

0.0219

0.0067

0.0238

0.0072

4

0.0099

0.0218

0.0045

0.0207

0.0045

0.0281

0.0062

0.0303

0.0065

5

0.0099

0.0253

0.0052

0.0250

0.0044

0.0344

0.0063

0.0369

0.0066

6

0.0099

0.0278

0.0052

0.0283

0.0035

0.0397

0.0055

0.0423

0.0058

7

0.0099

0.0332

0.0055

0.0310

0.0035

0.0446

0.0053

0.0471

0.0056

8

0.0099

0.0385

0.0053

0.0331

0.0033

0.0489

0.0048

0.0512

0.0052

9

0.0099

0.0436

0.0051

0.0350

0.0036

0.0533

0.0047

0.0549

0.0052

10

0.0099

0.0470

0.0035

0.0366

0.0029

0.0565

0.0035

0.0578

0.0043

TMD

- - Table 4: Maximum displacements and interstory drifts of the structure under the four earthquakes records to Scenario 1. 0.0903 - 0.1031 - 0.1300 - 0.1875

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