MODELLING OF HUMAN INDUCED STRUCTURES LATERAL FORCE ON

Abstract

This work discusses the problem of large amplitude lateral vibrations of bridges induced by crowds of pedestrians. A literature review gives the background of the some of the analysis so far done to find the different causes of failure of footbridges, this issue attracted great public attention. The possibility of excessive lateral vibrations is a serious threat to the design. The problem of influence of walking people on footbridge vibration properties, such as the natural frequency and damping is not well understood. Some of important causes like excessive load at a time, crowd density is one of the major cause of failure. To overcome the above problem the strength of new structural materials has to be increased to take more and more attention for crowd test. First the effect of increasing number of persons on bridge is analyzed in ANSYS. It shows the frequency of vibration values goes on increasing with number of persons and the rate of increase of damped frequency decreases with it. Secondly number of people was kept same and the effect of different on dynamic behavior of the bridge was investigated. It shows the value of damped frequencies decreases with equal spacing between them and also the symmetry plays an important role in increasing or decreasing the damped natural frequency. Unsymmetric orientations seems to have higher damping frequencies and lower damping ratios as compared to symmetric orientations.