The effectiveness of tuned mass friction damper (TMFD) in reducing undesirable resonant response of the bridge subjected to multi-axle vehicular load is investigated.A Taiwan high-speed railway (THSR) bridge subjected to Japanese SKS (Salkesa) train load is considered.The bridge is idealized as a simply supported Euler–Bernoulli beam with uniform properties throughout the length of the bridge, and the train’s vehicular load is modeled as a series of moving forces. Simplified model of vehicle, bridge and TMFD system has been considered to derive coupled differential equations of motion which is solved numerically using the New mark’s linear acceleration method. The critical train velocities at which the bridge undergoes resonant vibration are investigated. Response of the bridge is studied for three different arrangements of TMFD systems, namely, TMFD attached at mid-span of the bridge, multiple tuned mass friction dampers (MTMFD) system concentrated at mid-span of the bridge and MTMFD system with distributed TMFD units along the length of the bridge. The optimum parameters of each TMFD system are found out. It has been demonstrated that an optimized MTMFD system concentrated at mid-span of the bridge is more effective than an optimized TMFD at the same place with the same total mass and an optimized MTMFD system having TMFD units distributed along the length of the bridge. However, the distributed MTMFD system is more effective than an optimized TMFD system provided that TMFD units of MTMFD system are distributed within certain limiting interval and the frequency of TMFD units is appropriately distributed.

The effectiveness of tuned mass friction damper (TMFD) in suppressing the dynamic response of the structure is investigated. The TMFD is a damper which consists of a tuned mass damper (TMD) with linear stiffness and pure friction damper and exhibits non-linear behavior. The response of the single-degree-of-freedom (SDOF) structure with TMFD is investigated under harmonic and seismic ground excitations. The governing equations of motion of the system are derived. The response of the system is obtained by solving the equations of motion, numerically using the state-space method. A parametric study is also conducted to investigate the effects of important parameters such as mass ratio, tuning frequency ratio and slip force on the performance of TMFD. The response of system with TMFD is compared with the response of the system without TMFD. It was found that at a given level of excitation, an optimum value of mass ratio, tuning frequency ratio and damper slip force exist at which the peak displacement of primary structure attains its minimum value. It is also observed that, if the slip force of the damper is appropriately selected, the TMFD can be a more effective and potential device to control undesirable response of the system.

The effectiveness of passive multiple-tuned mass friction dampers (P-MTMFDs) over a single passive-tuned mass friction damper (P-TMFD) is investigated. The governing differential equations of motion are solved numerically using state-space method. The response of a five-story structure is investigated for four considered earthquake ground motions. The number of P-TMFD units of P-MTMFDs is varied and the response of five-story structure with single P-TMFD is compared with the response of the same structure with P-MTMFDs. A parametric study is also conducted to investigate the effects of important parameters like number of P-TMFD units in P-MTMFDs, frequency spacing, mass ratio, tuning ratio and damper slip force. It is found that at a given level of excitation; an optimum value of considered important parameters exists at which the peak displacement of structure attains its minimum value. The response time history of the structure with single P-TMFD and P-MTMFDs, with respect to their optimum parameters is compared. It is found that the P-MTMFDs are more effective in controlling the response of the structure to which it is attached in compare to the single P-TMFD having same mass.

The effectiveness of multiple tuned mass friction dampers (MTMFD) for vibration control of structure over a single tuned mass friction damper (STMFD) is investigated. A five story structure supported with MTMFD is considered and the governing differential equations of motion are derived. The response of the structure under four selected earthquake ground motions is obtained by solving the equations of motion numerically using the state space method. The number of damper in MTMFD is varied and the response of five story structure with STMFD is compared with the response of the same structure with MTMFD. A parametric study is also conducted to investigate the effects of important parameters such as number of dampers in MTMFD, damper frequency spacing, mass ratio, tuning ratio and damper slip force. It is found that for a given structural system and level of excitation an optimum value of the parameters (i.e. frequency spacing, tuning ratio and damper slip force) exists at which the peak displacement of structure attains its minimum value. The response time history of the structure with STMFD and MTMFD with respect to their optimum parameters is compared. It is found that the MTMFD is more effective in controlling the response of the structure in comparison with the STMFD having the same mass.