Effect of human-induced dynamic loading and its mitigation on pedestrian steel truss bridges

Abstract

Vibration challenges in lightweight pedestrian structures, such as footbridges, have been extensively studied, particularly following the notable lateral vibrations observed during the opening of the London Millennium Bridge on June 10, 2000. This incident underscores the critical need for a deeper understanding of the dynamic behavior of pedestrian bridges subjected to human-induced loads. This study focuses on the dynamic responses of pedestrian steel truss bridges under various loading conditions, including walking, jogging, and crowd-induced vibrations. Finite element analysis is used to identify critical parameters such as the fundamental frequency, acceleration, and damping and evaluate these parameters against the comfort criteria specified in BS EN 1991-2: 2003. Initial findings revealed that acceleration values exceeded the acceptable limits, prompting structural modifications to enhance mass, stiffness, and damping properties. Additionally, incorporating tuned mass dampers as a mitigation strategy demonstrated significant efficacy, achieving up to a 90% reduction in deck acceleration. The results provide valuable insights into optimising pedestrian bridge designs to improve both structural performance and user comfort, contributing to safer and more resilient infrastructures.