Research Article
Identification of Sudden Stiffness Change in the Acceleration Response of a Nonlinear Hysteretic Structure
Table 4
The relative errors between identified parameters and actual model parameters.
| Case | Seismic excitation | Relative error (%) | k1 | k2 | ζ1 | ζ2 | Y | α | β | γ | n |
| S1 | (a) El-Centro earthquake | 0.19 | 0.09 | 7.00 | 3.00 | 3.24 | 10.00 | 10.00 | 4.00 | 3.00 | (b) Kobe earthquake | 0.15 | 0.09 | 6.00 | 8.50 | 5.29 | 0.00 | 12.00 | 14.00 | 2.50 | (c) Northridge earthquake | 0.36 | 0.06 | 2.00 | 1.00 | 10.22 | 0.00 | 22.00 | 22.00 | 1.50 | Average values | 0.23 | 0.08 | 5.00 | 4.17 | 6.25 | 3.33 | 14.67 | 13.33 | 2.33 |
| S2 | (a) El-Centro earthquake | 0.50 | 0.18 | 4.50 | 8.00 | 1.93 | 10.00 | 6.00 | — | 0.50 | (b) Kobe earthquake | 0.01 | 0.10 | 6.00 | 9.00 | 0.78 | 0.00 | 2.00 | — | 2.00 | (c) Northridge earthquake | 1.15 | 0.44 | 19.00 | 4.50 | 0.42 | 0.00 | 8.00 | — | 3.50 | Average values | 0.55 | 0.24 | 9.83 | 7.17 | 1.04 | 3.33 | 5.33 | — | 2.00 |
| S3 | (a) El-Centro earthquake | 0.21 | 0.06 | 1.50 | 12.00 | 0.67 | — | 4.00 | — | 0.50 | (b) Kobe earthquake | 0.48 | 0.07 | 7.50 | 8.00 | 1.36 | — | 4.00 | — | 3.50 | (c) Northridge earthquake | 0.08 | 0.36 | 14.00 | 2.50 | 0.64 | — | 8.00 | — | 1.50 | Average values | 0.26 | 0.16 | 7.67 | 7.50 | 0.89 | — | 5.33 | — | 1.83 |
| S4 | (a) El-Centro earthquake | 0.41 | 0.09 | 4.00 | 8.50 | 6.18 | 10.00 | 10.00 | 22.00 | — | (b) Kobe earthquake | 0.10 | 0.09 | 8.00 | 8.00 | 5.82 | 0.00 | 12.00 | 16.00 | — | (c) Northridge earthquake | 0.29 | 0.01 | 8.00 | 0.50 | 2.73 | 0.00 | 4.00 | 12.00 | — | Average values | 0.27 | 0.06 | 6.67 | 5.67 | 4.91 | 3.33 | 8.67 | 16.67 | — |
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