Dynamic Analysis of Suspension Footbridges under Human-induced Vibrations and Near-field Earthquakes–Soti Ghat Bridge in Nepal

Suspension footbridges are mainly under the influence of pedestrians’ loads. In addition to the forces caused by pedestrians during the structure’s lifetime, natural forces such as wind and earthquake also affect these structures. The effects of wind force on the suspension bridges are generally considered in the design process of the structure due to the high repetition of this phenomenon and lightweight of these structures but the earthquake forces are ignored due to the low probability of occurrence, low mass, and the high flexibility of these structures. This study aimed to investigate the dynamic behavior of suspension footbridges under the influence of the coincidence of pedestrians loading and earthquake forces. The final finding of this study was the impact of the earthquake on the suspension footbridges, which caused a change in the acceleration and forces of the bridge cables. It was found out that the simultaneity of human loading and earthquake forces increases the response of the lateral acceleration of the structure, and this increase is affected by the acceleration of earthquakes. Moreover, the lateral acceleration response of the structure changes during the pedestrians’ movement, like the vertical acceleration response, but its amount is small at different speeds and does not cause any difficulty in operating the structure.