When we talk about amazing bridges, we usually mean bridges designed to be crossed by cars or at at least trains. The bridges that spark most interest are, for example, the longest bridges in the world, created to span stretches of sea or lakes, or the highest bridges, built to span the deepest gorges. But it must be said that pedestrian bridges can also amaze. Take the famous Segunda Circular Bridge in Portugal, for example, whose bright orange colour and branching structure remain imprinted in the memory of all who see it; or the Denver Millennium Bridge, a cable-stayed pedestrian bridge that has become a symbol of the city due to its spectacular appearance; or the Scale Lane Bridge in the city of Hull, with its original apostrophe shape and the unusual movement it makes to allow boats to pass underneath. The Helix Bridge in Singapore most certainly features among the most fascinating bridges in the world, astounding all tourists who visit this city-state with its absolutely unique structure inspired by the DNA double helix. In this article we take a look at the story of the design and construction of this famous coiled double helix bridge, its distinctive features and its dimensions.
The Helix Bridge in Singapore: the dimensions
The Helix Bridge in Singapore, officially known as The Helix, links the Marina Centre with Marina Bay, near the Benjamin Sheares Bridge. It extends for a total of 280 metres, covered by canopies with five bays: three of these extend for 65 metres, while two are smaller, measuring 45 metres. Another unusual feature of the bridge, apart from its spiral structure, is that it does not follow a straight line, but instead it follows a slight curve.
The construction of the DNA-shaped bridge
Behind the Helix Bridge in Singapore was a team of international architects and engineers: the Australian architects Cox Architecture, the engineers Arup, and finally the Singapore Architects studio. As we shall see later, the design team had to comply with some very particular requirements in constructing the bridge, including Feng Shui criteria. Construction of the bridge began in 2007, and was completed on 24 April 2010, but the full opening of this pedestrian crossing did not take place until 18 July of that year.
The work proceeded from North to South, assembling on site the various pieces, which had been constructed specifically in order to be easily transported along the roads of Singapore. We should add that a mock-up of the metal structure (more specifically, in duplex stainless steel) had already been constructed on the site at the start, in order to identify any errors in the manufacture beforehand.
In order to facilitate the works, a temporary truss bridge was constructed on site in order to span that part of the river; the different segments of the truss that made up the arches were positioned using two mobile cranes, with most of the work being carried out at night in order to minimize the disturbance caused by closing the canal. Once the temporary bridge was constructed, it was possible to position a crane in the centre of it so that it could lift the prefabricated horizontal sections into position.
The Feng Shui requirements
Singapore’s architecture, especially the most recent buildings constructed near Marina Bay and the city’s financial centre, is strongly influenced by the Chinese Feng Shui philosophy. As we know, this ancient Taoist geomantic art provides various indicators on ways to design and build: thanks to its lightness, its guaranteed luminosity, its protection from wind and rain, and its beauty, the Helix Bridge has received the approval of the Feng Shui Committee.
Distinctive features of the Helix Bridge
The most original aspect of the Helix Bridge in Singapore is definitely the way it represents the iconic DNA structure. It is not limited simply to representing the helix of nucleic acid containing genetic information, however. If you walk along the bridge at night, in fact, it is easy to see from the level of the bridge surface the pairs of coloured letters C and G and A and T, illuminated in red and green after sunset, representing cytosine, guanine, adenine and thymine, that is, the four bases of DNA. We should also add that the decision to represent the “left handed DNA-like” design won the bridge a place in The Left Handed DNA Hall of Fame 2010. This is by no means the only award that the Helix Bridge has won: for example, it was also awarded “World’s Best Transport Building” in the World Architecture Festival Awards.
The overall design of the bridge is also unique as a result of the fritted glass canopies that create a roof, protecting people from rain and providing – along with the steel mesh – some shade in the middle of the day. Four viewing platforms are positioned along the sides of the bridge – each able to accommodate up to 100 people – from which people can observe the boats sailing along the river, as well as the bridge itself, of course.