The vibration problem of bridges under moving loads is getting more sensitive as construction of long-span bridges is increased and the highspeed railway, such as TGV is under construction in Korea. Vibration induced by the heavy moving vehicles may significantly increase the maximum internal stress of bridges and deteriorate serviceability. Vibration control using control devices is very efficient way to suppress the response of bridges, thus to enhance the structural safety and serviceability of bridges. Vibration control devices are mainly divided as passive, active and semi-active types by their energy depression mechanism.
In the study, vibration control using tuned mass damper(TMD) is adopted. TMD, a kind of passive type control device, has a variety of merits in that it has permanent service time, and needs easy management and maintenance efforts and no external power supplying sources. TMD is tuned to the 1st dominant vertical mode and installed in the middle of bridges. The dynamic response of bridges subjected to moving loads can be obtained using moving mass model which considers the effects of the vehicle mass, thus TGV highspeed trains are modeled as 2 DOF system consisting of wheel and body. To show the efficiency of TMD in the case of single span and 3-span bridges, the midpoint vertical displacements and their fast Fourier transform results are compared before and after the installation of TMD.
