Vibration Testing, Analysis, and Human-Structure Interaction Studies of a Slender Footbridge

Abstract

The high strength of construction materials has allowed the design of elegant and architecturally appealing footbridges that are safe against static loads but may be susceptible to large vibrations when crossed by pedestrians. The low natural frequencies and damping of these systems can result in excessive or annoying movements. This paper presents two studies on the vibration serviceability of a footbridge. In the first part, details of the vibration testing and analysis of a slender two-span steel footbridge will be discussed. Vibration tests on the structure were conducted to verify the computer modeling and results of the dynamic analyses. The accuracy of the computer model was evaluated by comparing various dynamic properties and criteria. Lessons learned from the comparison of the results of the tests and analysis are presented. The second part of this paper presents a study of human-structure interaction (HSI) on the dynamic behavior of the footbridge. Results of vibration tests with a number of human subjects are compared with those from the computer modeling. They demonstrate the validity of the human models used, and the effect of humans on the dynamic properties and response of the structure.