102 M. Sheibani et al. Simulation No. 0 10 20 30 40 50 60 70 80 90 100 Normalized α 0 0.5 1 1.5 1st mode shape 2nd mode shape 3rd mode shape Fig. 13.5 Normalized scale factors—Traffic case 1 Simulation No. 0 10 20 30 40 50 60 70 80 90 100 Normalized α 0 0.5 1 1.5 1st mode shape 2nd mode shape 3rd mode shape Fig. 13.6 Normalized scale factors—Traffic case 2 Simulation No. Normalized α 0 0 10 20 30 40 50 60 70 80 90 100 0.5 1 1.5 1st mode shape 2nd mode shape 3rd mode shape Fig. 13.7 Normalized scale factors—Traffic case 3 Simulation No. Normalized α 0 0 10 20 30 40 50 60 70 80 90 100 0.5 1 1.5 1st mode shape 2nd mode shape 3rd mode shape Fig. 13.8 Normalized scale factors—Traffic case 4 The unscaled mode shapes which are extracted from the free flow traffic condition, the scaled modes using scale factors obtained by the proposed method, and the exact modes calculated using FEM model are shown in Fig. 13.9 for the first three modes of the first traffic case for one random simulation. It should be noted that in order to compare mode shapes extracted from modal tests and the FEM extracted mode shapes, the size of mass and stiffness matrices are reduced using the Guyan reduction technique [20]. The scaled mode shapes extracted from OMA and the corresponding modes calculated by FEM model are also compared using Modal Assurance Criterion (MAC). Figure 13.10 shows the complete correlation of these two conditions.
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