Development of a human-structure dynamic interaction model for human sway for use in permanent grandstand design

This paper details a first attempt to develop a simple human-structure dynamic interaction (HSDI) model for vibration serviceability design of permanent grandstands subject to crowd sway. To date, extensive research has been conducted on vertical crowd-induced vibrations to understand interaction mechanisms and enable engineers to account for them. Similar mechanisms have not yet been fully understood or researched in the lateral plane. This, alongside the limited, verified measured response data has led to incomplete design assessment methods. In this work, an effective two-degree-of-freedom spring-mass-damper-actuator system is developed to represent co-ordinated spectators swaying laterally in the side-to-side direction on a real grandstand. The dynamic properties attributed in the constituents of the model are determined by curve fitting of laboratory-scale human sway data and the modal analysis of the grandstand’s finite element model. The comparison of the modelling output against existing serviceability criteria approaches illustrates potential conservatism in current practice. Namely, when the maximum responses and forces were examined as part of the integrated dynamic system a notable drop-out effect was observed. Although further research is required to validate and calibrate the proposed simple human-structure sway model for individuals and crowds, the observations qualitatively determine the significance of explicitly considering human-structure interaction in the design and assessment of permanent grandstands. Such effects may lead to construction cost savings in addition to unwanted limitations on architecture, hospitality areas and spectator circulation.