Reaction Spectrum Comparative Analysis of Seismic Performance of 62 m CFST Bridge with Curved-String Truss before and after Reinforcement

Table 2

The first 10-order natural vibration characteristics of the bridge after reinforcement.

Modal number	Frequency (Hz)	Cycle (s)	Mode shape characteristics
1	2.103	0.476	Transverse first-order vibration of the main truss
2	4.010	0.249	Transverse second-order vibration of main truss
3	5.164	0.194	Vertical first-order vibration of the whole bridge
4	5.741	0.174	Full bridge torsion of the first-order vibration, vertical vibration of the bridge deck
5	5.935	0.168	Transverse third-order vibration of the main truss
6	6.433	0.155	Vertical second-order vibration of the whole bridge
7	6.816	0.147	Full bridge torsion second-order vibration, vertical vibration of the bridge deck
8	8.464	0.118	Transverse fourth-order vibration of the main truss
9	8.628	0.116	Vertical third-order vibration of the whole bridge
10	9.078	0.110	Full bridge torsion third-order vibration, vertical vibration of the bridge deck