Study On Parameter Optimization And Performance Of TVMD For Seismic Control Of Continuous Beam Bridges Under Stochastic Excitation

Tuned Viscous Inertial Damper(TVMD),as a kind of energy dissipation device,has become a research hotspot because it can effectively suppress the seismic response of bridge structures.the ground motion input is a stochastic process with nonstationary characteristics.It was usually simplified to a stationary stochastic process in the calculation for ease of analysis.However,nonstationary stochastic excitation has a significant impact on the seismic response of long-period bridge structures.In this paper,the parameter optimization and damping performance of TVMD for continuous beam bridges under stationary and nonstationary stochastic excitation are compared and studied.The main contents are as follows:(1)Taking the main structure of single degree of freedom as an example,the damping optimization system of TVMD under stochastic ground motion input is established.The generalized pattern search algorithm is used to optimize the TVMD parameters.By comparing with the optimization results of the traversal search method,the validity of the pattern search algorithm to optimize the TVMD parameters is confirmed.Furthermore,the influence of nonstationary ground motion parameters on TVMD optimization parameters and damping performance are discussed and analyzed.(2)A two-degree-of-freedom simplified model of continuous beam bridge is established,and the parameter optimization,influence parameters and damping performance of TVMD on the simplified model under stationary and nonstationary stochastic excitation are studied.Furthermore,a multi-degree-of-freedom fine model of continuous girder bridge is established,and the parameters of TVMD are optimized under two stochastic excitations,namely stationary and nonstationary,from two typical situations of shock absorption analysis in the longitudinal and transverse directions,and the shock absorption effect of TVMD optimized under stochastic excitations is clarified.(3)Considering the influence of the dynamic characteristics of the structure on the damping effect of TVMD,a multi-degree-of-freedom fine model of continuous beam bridges with long period characteristics under multi-span and different pier heights is established,and TVMD parameter optimization and damping performance under stationary and nonstationary stochastic excitation are compared and analyzed.It is clarified that the TVMD optimized by nonstationary stochastic excitation method can reduce the displacement response peak value of the structure more effectively,while the optimized TVMD under stationary stochastic excitation is more effective in damping cumulative damage of the structure.