Table 1 Summarisation of the advantages and limitations of the force vibration test
From: An Overview: The Application of Vibration-Based Techniques in Bridge Structural Health Monitoring
Forced vibration testing (FVT) | ||
|---|---|---|
Excitation instrument | Advantages | Limitations |
Impact hammer | A straightforward approach to excite the structure Fast in their application and tests can be quickly repeated a large number of times Giving a wide-band input that may trigger many vibration patterns | Susceptible to input noise Higher impact hammer masses can cause the risks of local damage Bridges must be closed to traffic during testing |
Eccentric rotating mass vibrators | Precise results for medium to short span structures with medium-to-high damping The input loading can be changed to meet the requirements of the test Can be operated at various frequencies Generating forces in more than one direction | The exciter needs laboratory testing to determine its parameters before its practical application Bridges must be closed to traffic during testing |
Servo-hydraulic shakers | Generate wide-band stimulation throughout the highest frequency range of interest | The size of the structure may be limited to the use of single input servo-hydraulic-based burst random noise excitation Bridges must be closed to traffic during testing |