Research On Pedestrian-induced Vibration And Comfort Of Footbridge Based On Stochastic Process

The pedestrian-induced vibration of footbridge has attracted wide attention along with the prominent role of footbridge in social life.The study on pedestrian-induced vibration includes pedestrian load,lateral vibration,vertical vibration,comfort and vibration reduction.The pedestrian-induced vibration of footbridge is essentially random vibration.The purpose of this dissertation is to use random vibration theory to analyze the pedestrian-induced vibration of footbridge,and use stochastic process to evaluate the comfort of pedestrians,in order to return to nature of footbridge random vibration.The main work and results are as follows:(1)The stochastic process and random vibration theory are introduced systematically.The random vibration theory is used to deduce the lateral and vertical vibration of the footbridge.The autocorrelation function is obtained which of the footbridge displacement under the pedestrian random load.(2)The pedestrian comfort is evaluated by stochastic process method,and recommended evaluation indicator is given.The significance and essence of stochastic process for comfort evaluation are expounded.The significance in the stochastic process is explained which of the comfort evaluation indicators from many codes,and their limitations are also pointed out.At the same time the limitations of recommended evaluation method are pointed out too.They indicate that pedestrian comfort evaluation is a very complex work.There are still large research spaces in evaluating pedestrian comfort with stochastic process.(3)The "locking" phenomenon of footbridge lateral dynamic instability is explained,and the critical number is derived.The bridge vibration reduction is introduced,and the principle and design method of TMD system are emphatically introduced.(4)Combining with an example of a cable-stayed bridge in China,the random vibration analysis is carried out.Through the interpretation of results,the recommended evaluation method and the theoretical derivation in this dissertation are validated.It shows that the recommended evaluation method is more comprehensive and clearer than others,the theoretical derivation is correct,reliable,and it can be analyzed by finite element software which has high computing efficiency.