The Helix Bridge, previously known as the Double Helix Bridge, is a pedestrian bridge linking Marina Centre
with Marina South in the Marina Bay area in Singapore
. It was officially opened on 24 April 2010 at 9 pm, however only half was opened due to ongoing construction at the Marina Bay Sands. It is located beside the Benjamin Sheares Bridge and is accompanied by a vehicular bridge, known as the Bayfront Bridge. The entire bridge was opened on 18 July 2010 to complete the entire walkway around Marina Bay.
The bridge complements other major development projects planned in the area, including the highly anticipated Integrated Resort Marina Bay Sands, Singapore Flyer, Gardens by the Bay and the 438,000 m² business and financial centre which will be ready by 2012.
The design consortium is an international team comprising Australian architects the Cox Group and engineers Arup, and Singapore based Architects 61. Canopies (made of fritted-glass and perforated steel mesh) are incorporated along parts of the inner spiral to provide shade for pedestrians. The bridge has four viewing platforms sited at strategic locations which provide stunning views of the Singapore skyline and events taking place within Marina Bay. At night, the bridge will be illuminated by a series of lights that highlight the double-helix structure, thereby creating a special visual experience for the visitors.
From the outset, the project posed several challenges. There was a desire for the plan view of the bridge to be curved in an arc, such that it joins the foreshore promenades on either side seamlessly. Furthermore, it was desirable to create a lightweight structure, in contrast to the adjacent 6-lane vehicle bridge which is rather heavy in appearance.
Due to the tropical climate, the brief also required the bridge to provide shade and shelter against direct sunshine and heavy rainfall. The combination of these factors, together with the desire to create a landmark structure, led to a novel and unique design. The bridge was designed using BS 5950 in combination with a design guide from the SCI.
Extensive numerical analysis was completed in order to explore possible solutions, using the engineer’s in-house structural optimisation software. This enabled a method to be found of linking the two helices. It also ensured that the steel sections are used to their maximum capacity in supporting the pedestrian deck, shade canopies and light fixtures. Prior to specifying materials, or even finalising the designs, the bridge was fully modelled using three-dimensional software in order to visualise its form and geometrical compatibility, as well as to visualise the pedestrian experience on the bridge.
Before any work began on the actual bridge a mock-up was made of carbon steel to try and preempt certain difficulties. Fabrication of the elements worked from the North to the South, components being assembled into segments that could manage the Singapore roads. A trial assembly was done before delivery to site to identify any prefabrication errors.
The duplex stainless steel used is susceptible to contamination by carbon or zinc dust. So a dedicated workshop was specially set up to keep members for the Helix separate from other carbon and galvanized steels.