Dynamic analysis of Footbridge to Eurocode (case study on Leventis Footbridge, Aba Road, Port Harcourt)

This research project presents a dynamic structural analysis of footbridges as per Eurocode (case study on Leventis Footbridge, Aba Road, Port Harcourt). The footbridge was simulated using a commercial finite element software; Midas FEA. The crowd-footbridge is modelled as a structural oscillator to which some external load is applied. Therefore, the crowd is taken as an imposed load rather than as a dynamical system. The eigenvalue analysis was carried out to obtain the natural frequency ⍵n, which is obtained as the eigenvalue of the characteristic equation and the corresponding mode shape is obtained as the eigenvector of the characteristic equation. The values are compared to Eurocode specification for comfort criteria on footbridges. Time history analysis was also carried out. This method was used to construct time histories of variables, such as displacement and acceleration, by calculating the response at the end of a succession of very small time steps. The peak deck acceleration is obtained and compared to Eurocode specification for comfort criteria on footbridges. From the time history graph, it was observed that the maximum acceleration of the footbridge is 0.56m/s2 which is greater than the value stated in the Eurocode standard specification of 0.5m/s2 for maximum comfort. This implies that the footbridge acceleration obtained is not satisfactory and that some measures need to be taken in order to remediate this effect and control the vibrations. Some measures to reduce vibration are recommended