Research On Parameter Analysis And Performance Of Tibds For Seismic Control Of Continuous Beam Bridges

As the critical parts of the lifeline project,bridges will bring huge disasters when they are destroyed during the earthquake.In practical engineerings,various dampers have been used to absorb and dissipate the seismic energy inputed into the primary structures,and to mitigate the seismic responses of the bridge.The tuned inerter based dampers(TIBD)is a new type of damper devices,which can enlarge their actual mass level to a thousand times and use the inertia force and tuning effect to realize the seismic control purpose of bridge.The tuned viscous mass damper(TVMD)and the tuned inerter damper(TID)belong to the new type of damper devices.In this paper,the continuous beam bridge in practical engineering is taken as an example to study parameter optimization and damping performance of the TIBDs.The main works are as follows:(1)Based on the existing modeling methods of continuous beam bridge,a typical continuous beam bridge with three spans is simplified as two different models for the seismic response analysis,i.e.simplified model with two degree of freedoms and fine model with multiple degree of freedoms,by which the seismic control performance of the TVMD and TID to the continuous beam bridge are studied.Then the structure with single degree of freedom is taken as an example to study the damping mechanism of TVMD and TID.The output force of TIBDs are divided into two parts,i.e.the elastic force and damping force,whose calculation formulas are inferred to compare the influence of equivalent stiffness and damping on the seismic control performance of the TVMD and TID.(2)Takeing the simplified model with two degree of freedoms as the analysis model,the dynamic magnification factors from external excitation to the critical responses are regarded as evaluating indicators to achieve parameter optimization and analyse the influence of primary structure and damper parameters on the seismic control performance.Then based on the fine model with multiple degree of freedoms,two kinds of typical states for the seismic response analysis,i.e.the along state and the cross state of bridges are proposed.H2 optimization method is applied to optimize parameters of TIBDs,and compared with the traditional viscous damper,the efficient damping performance for multiple modes of continuous beam bridges is studied.Research shows the two kinds of TIBDs both have obvious seismic control effect for the single and multiple modes of continuous beam bridges.(3)Considering the influence of dynamic characteristics of structures on seismic control performance of dampers,the fine models with different sizes of piers and spans are set up to analyse the influence of piers and spans on the performance of TIBDs.Research shows TIBDs have excellent damping performance for continuous beam bridges with different sizes of piers and spans,however the effect will decrease in the wake of the increase of piers and spans.Finally,a typical continuous beam bridge with five spans is simplified as fine model with multiple degree of freedoms to study the damping performance of the TIBDs,and research shows that TIBDs also have efficient damping performance for the five spans continuous beam bridges.