Research Of TMD Vibration Controll For Pedestrian Bridge Based On Fish Algorithm

With the development of new high strength material and widely used, the structure of the pedestrian overpass is developing in the direction of large span and slender width, which causes its natural frequency reduced. If the natural frequency of the bridge is same to the pedestrian load frequency, the bridge will has large vibration,accidents will occur frequently. Tuned Mass Damper,as a relatively perfect vibration control system,is widely used in the bridge vibration reduction now.The bridge vibration reduction is related to the optimization of the parameters of TMD, but the optimization is a multi-objective optimization problem,solving mainly relies on the empirical formula method because it is difficult to solve multi-objective optimizationproblems. However, the fish algorithm, as a kind of new intelligent algorithm, has been applied in many areas now because of its simple principle, fast convergence rate and high precision.Therefore, based on the traditional Den Hartog TMD parameters design method, this paper proposes a method based on fish algorithm to search for TMD optimum parameters to meet the requirements of bridge vibration, it mainly includes the following aspects:Firstly,the paper analyzes the several kinds of common model of the pedestrian load in theory, builds the pedestrian load model, analyzes the pedestrian load influence on bridge vibration.Combining with the characteristics of the pedestrian bridge, the paper builds the bridge model and does the modal analysis, the pedestrian load is loaded into the model,the pedestrian load on the dynamic response of a pedestrian bridge is studied.Secondly, analyzes TMD undamped-structure undamped,TMD damped-structure undamped and TMD TMD damped-structure damped in theory; With the traditional TMD design method, the paper designs variety of different mass ratio TMD system, load TMD model in Midas Civil, and researches the bridge’s dynamic response after vibration reduction.Finally, establish the objective function of the structure dynamic magnification coefficient, use the fish algorithm to optimize the function, search the optimal parameters of TMD. With the parameters of the load to the model, the paper compares the bridge vibration reduction effect of the TMD system between before and after optimization, the results show that the algorithm in the search for TMD optimum parameters has certain feasibility and validity.