The Damping And Simplified Algorithm Research On Footbridge-TMD Located In Tianjin Stadium

With an improving of the using conditions, material performance and landscaperequirement, the footbridge becomes a long-span, soft and low damping structure. Inrecent years, the strong vibration by crowd occurs, seriously affecting the walking comfort.The issue catches more public attention. Currently, during the footbridge design, it usuallyuses the finite element method to evaluate the comfort, however, this article mainlystudies the simplified calculation method. Based on the introduction of walking load andthe theory of human-induced vibration of footbridges, by taking a multi-span continuousbridge as an example, the damping measures and the simplified calculation of vibrationresponse of the structure after adding damping device are studied. The main contents areas follows:(1) Introducing the pedestrian load model and main calculation theory of the modemethod, and it also uses the forced vibration theory to analyze the vibration responseunder the single person or the crowd.(2) This paper uses the finite element method and SDOF resonance theory tocalculate vibration response of the footbridge, separately, assesses the footbridge comfort,and designs appropriate TMD(Tuned Mass Dampers) parameters for the structure, also,analyzes the damping effect of TMD.(3) Choosing the flexural vibration model function is important to calculate thefootbridge vibraiton responses. In this paper, the deflection curve under uniform loads isinvolved in the calculation instead of the vibration curve. We can determine the value ofseveral basic parameters based on the deflection curve in the simplified calculation andTMD design. It could draw a clear comparision between two results in the2nd point andjustify the modal function,while the damping effect of TMD can also justify the modalfunction.(4) This paper calculates the vibration response of the continuous bridge-TMD in thelight of the SDOF structure-TMD model. In this paper, two methods that are simple andeasier to understand for solving equations of motion are given; also, it analyzes the influence factors to the simplify calculation and vibration response.Vibration mode function and the simplified calculation method proposed in this papercan provide a reference for the preliminary design of continuous bridges, but it still needsmore project examples to verify its accuracy.