Abstract: s:The increase of train speed may induce large vibration in lightweight bridge piers.MTMD(Multiple Tuned Mass Damper)is hence proposed for the transverse-vibration control.Assuming the bridge pier to be a single-degree-of-freedom system,a model of pier-MTMD system is developed and its motion differential equation derived.The influences of different MTMD design parameters on the acceleration magnification factor are analyzed.The results show that the frequency width,damping ratio,mass ratio,central frequency ratio and total TMD number of MTMD influence the vibration control effects.It is necessary to optimize these parameters.The MTMD for a lightweight bridge pier was designed and its transverse-vibration control effects analyzed.The results showed that MTMD can suppress the transverse vibration of lightweight railway-bridge piers effectively.But the control effect is related to the vibration characteristic.