Simulation and Measurement of Human-Induced Vibrations of the Beijing Olympic Watchtower with Tuned Mass Dampers

Abstract

The Beijing Olympic Watchtower (BOW) is a landmark building with irregular shape and complex structural configuration; however, excessive human-induced vibrations of the sightseeing platform may occur during service, resulting in discomfort or panic of sightseers. Therefore, tuned mass dampers (TMDs) were designed to control the maximum acceleration under human activities. This paper presents the finite-element (FE) simulation of the vibrations under different human densities and moving frequencies. Field vibration tests on the fifth sightseeing platform of the BOW were further conducted to study the dynamic behavior of the platform and to validate the effectiveness of TMDs. The tests consisted of two free vibration modal tests (before and after the construction of the floor surface layer) and tests to measure the dynamic responses with controlled crowd moving. It is observed that prior to the use of TMDs, the accelerations significantly exceeded the threshold value, and there was lateral torsional vibration of the platform; resonance occurred as the crowd moved at 2.5 Hz, resulting in significant human discomfort. After the installation of TMDs, the human-induced responses were significantly mitigated, although due to the absence of a floor surface layer during the field measurement, there were some differences between the designed and measured modal frequencies, and the TMDs may not have fully reached their capacity.