Analysis Of Steel Pedestrian Bridges Dynamic Response Of Pedestrian-induced And Vehicle-induced And Comfort Assessment

With the development of city construction and the city road widen,the steel pedestrian bridges have been more and more widely used. As the structure of steel pedestrian bridge is light and soft, the external load excitation in the integrated environment may lead to a large vibration to footbridges, which includes two aspects: one is vibration caused by pedestrian load and another is vibration caused by vehicle passing through the footbridge. Vibration not only brings some harm to structure performance which can reduce the life of footbridges, but also influences the comfort of pedestrians on the footbridges, makes the pedestrians feel panic,and reduces the functions of footbridges. As the dynamic properties of the steel pedestrian bridge are different because of its structure and quality, it need targeted analysis. This article takes two-span steel pedestrian bridge of Hefei for example, using finite element method, to analyze dynamic characteristics and dynamic time history of pedestrian bridges caused by pedestrian and vehicle load, and to study reasons for footbridge vibration and to assess the footbridge comfort. The research content mainly includes:1. Characteristics of single pedestrian, crowd load model and calculation on pedestrian-induced vibration of footbridges are compared and discussed in detail, one is selected to use in the article. Pedestrian forces are expressed by Fourier series, that pedestrian-induced vibration can be simplified as forced resonance vibration.2. Road vibration theory caused by the traffic loads is described in detail. Reasons, propagation and characteristics are analyzed, also the classical semi-infinite soil theory of random vibration force and model of experienced theory widely used presently.3. Use finite element software MSC.MARC to establish three-dimensional solid model of steel pedestrian bridge of Hefei, to analyze static and dynamic characteristic of footbridges and to study the basic problem in the process of footbridge vibration. In the process of establish model, diaphragms and Stiffeners should be considered.4. On the basis of the dynamic characteristic study, using the transient state analytic method, carry on the dynamic time interval response analysis of the steel pedestrian bridges. Research in the pedestrian-induced and vehicle-induced steel pedestrian bridges vibration is done to identify the mail factors and causes. Then, analysis of vibration of the footbridge in the integrated environment is carried out by calculation of the joint action of two kinds of loads.5. Describe the method of the pedestrian bridges comfort level assessment. Use the evaluation criteria widely used in pedestrian bridges to assess the serviceability of the footbridge.