European highways are some of the most challenging feats of engineering in the modern world. They need to have the strength and capability to cater to a torrent of motorists, and due in large part to ‘advisory’ speed limits, these structures have to handle this high volume of cars at incredibly high speeds too. Apart from the obvious necessity of durability, the role of a highway is connectivity. This is especially important when considering a European highway, which often cross not just state, but international boundaries. In order to create a truly successful piece of infrastructure this connectivity and stability must be a shared focus.
Herein lies the major issue.
When assessing the design to be presented for the Stockholmsporten master plan competition in Sweden, the idea of resilient infrastructure and communication between international communities do not mesh well without a little innovation. Thankfully though, that innovation has been generously supplied by BIG, Grontmij and Spacescape.
Assessing the Issue
The challenge faced by this European design team was to create a solution for the newest gateway into Stockholm, known as the Hjulsta intersection, connecting E18 and E4, two major European highways on a three level intersection.
Designers saw that traditional methods of engineering and construction were simply isolating the four surrounding community sections of Barkaby, Järva By, Järva Friomráde and Tensta/ Spágadalen by the giant ‘x’ intersection that was the initial highway plan.
In addition to the disconnectedness of the surrounding areas, the noise levels created by this intersection were extreme in some communities.
Five Points of the Loop
Responding to these challenges, an innovative but simple design scheme was created, which won the support of the Swedish Transport Administration, and is now currently underway.
The basic design scheme is a juxtaposition of design simplicity and engineering complexity. The stark simplicity of creating a connection without isolating any community area is achieved by the ‘Green Loop’. The loop has the ability to link all different sections in a fluid motion, creating a liquid and linked environment that encompasses the 580,000 sqm of land space.
There are five different buildings that are a new possibility due to the space created by the loop. These new structures include a sports centre, a winter garden, a hamam bath, a “naturum” and a mosque on the five outlying points of the loop. In doing so, this creates public spaces to encourage social sustainability. BIG architects’ founder Bjarke Ingels says that the design follows the company’s common ideology of ‘hedonistic sustainability’.
Creating the Sphere
With connectivity accounted for, the project’s primary focus then shifts to urban development. This includes a necessity for sound blocks to shelter the surrounding communities from the road noise. Instead of traditional sound barriers, the design involves the creation of a valley in which the bypass will sit, with soil and earth cleared to make room for the E4 Stockholm bypass, used to create the edge of a new valley that will provide the project’s acoustic needs.
While this new valley will deal with the acoustic issues, the design also calls for something of a landmark, and this is where things get really interesting.
In order to create a visual that will be stylish, in addition to having a greater purpose, the project will feature ‘The Sphere’. Covered in a spray on reflective anti-glare coating, the sphere will allow the valley’s lush greenery surrounds to become a reflected icon, and encourage drivers to be more aware of their surrounds.
Held in place by three cables and a structural truss, the sphere weighs a monolithic 5, 953 kg with a capacity to reach 15, 5953 under the weight of snow or rain. Its lift is provided by the 15 degree temperature difference inside and outside of the massive structure, with high levels of internal pressure allowing it to keep its shape in heavy winds.
Perhaps the most incredible aspect of this engineering feat is the remarkable societal and environmental sustainability potential offered by the sphere. Potovoltaic cells on the surface of the sphere, will channel energy through the support trusses and into the neighbouring city. Not only will this create an energy production high enough to completely maintain the sphere, but the remaining 90% of the energy created, will be funnelled into 235 surrounding homes.
With future plans for the sphere to work in the production and storage of wind power it is apparent that this is one project that is not going to become stale. It’s an innovative solution that offers a great deal more than just an intersection remodel.