Serviceability Assessment of Footbridges Under Heel-Drop Impact Considering Human Structure Interaction

Abstract

The vibration serviceability of a long-span landscape footbridge was comprehensively investigated both experimentally and numerically. Specifically, the dynamic responses of the footbridge under heel-drop impacts, such as the peak acceleration and maximum transient vibration value (MTVV), were determined by tests, and the heel-drop loads were measured. In addition, the modal analysis was performed to obtain the natural frequencies, damping ratios, and mode shapes of the footbridge. As a result, the footbridge had low frequency (4.22[Formula: see text]Hz) and modal damping ratio (1.77%). Comparing the test results with the China design code, AISC design guide, and ISO standard, the footbridge generally exhibited satisfactory vibration perceptibility. A finite element (FE) model considering the interaction between human and structure was established and validated with the test results. To validate the human–structure interaction (HSI) model in the future with a simple heel-drop excitation test, a heel-drop load model is proposed. The ratio of root-mean-square (RMS) acceleration to peak acceleration is also proposed to calculate the MTVV conveniently.