Vibration serviceability of Helix Bridge, Singapore

Helix Bridge is a key feature of the iconic Marina Bay Sands development in Singapore. It usually functions as a pedestrian link between the Esplanade and Sands Casino/Hotel, but is occasionally used as a viewing platform for events in Marina Bay that have centred on a small purpose-built stadium opposite the bridge. To supplement the stadium capacity, integral cantilevered ‘pods’ have been built into the bridge. Because of its dual role, the Land Transport Authority of Singapore commissioned a vibration serviceability evaluation of Helix Bridge following a specification developed by Arup Australia. This evaluation was carried out in three stages. First, an experimental campaign comprising multi-shaker modal testing was used to estimate modal properties. Next, limited pedestrian and crowd testing directly evaluated the dynamic response to individuals and small groups walking, running or jumping. Finally, modal properties were utilised, with bespoke simulation software, to predict the performance of the bridge under extreme crowd loading using models specified in the most up-to-date design guidance on crowd loading for pedestrian bridges and stadia. The bridge performance proved to be acceptable, both in direct testing with small groups and in the simulations of large crowds.