The Olympic symbol consisting of five interlinked circles is stretched out and rotated until the links create a three-dimensional double helix formation in this bridge design, which is scheduled to become reality in Beijing in time for the Olympic Winter Games in 2022. China has already made it clear that it’s willing to go big when it comes to Olympic architecture, filling Beijing with a series of massive structures for the 2008 Summer Olympics, and it aims to make its next turn hosting just as memorable. The San Shan Bridge (3 Mountains Bridge) by architecture firm Penda will connect Beijing with the city of Zhangjiakou, where most of the outdoor events for the Games will take place.

Spanning China’s Gui River, the San Shan Bridge is supported by the double-helix structure made up of three sets of undulating steel arches that cross above and below the road surface, dipping into the water. The deck is suspended from the higher arches using high-strength steel cables in a woven pattern. Four vehicular lanes are edged with greenery, which separates the cars from pedestrian paths on either side. Using up to 5 times less steel than a conventional box girder bridge, the design is slim and lightweight in appearance despite its big visual impact.

The region surrounding the bridge is a popular recreation spot for locals and tourists alike, with booming growth leading to a need for more infrastructure. The bridge will not only provide a crucial (and highly memorable) artery from the city to the Olympic events, it’ll be a central component of the Beijing Expansion Masterplan. Nearly 1500 feet long, the bridge will take a few years to construct, but should be done by the time the Beijing Horticultural Expo 2019 rolls around.

Some of the concepts submitted for the new Nine Elms to Pimlico pedestrian bridge in London are rather – well – pedestrian, while others are so out-there they’ve been nicknamed ‘The Flaming Mouth of Hades.’ Spanning the Thames River, the bridge will link two very different parts of the city, and must be “technically rigorous and beautiful,” cyclist-friendly and well-engineered while providing headroom for river traffic.

The competition to design the bridge has drawn dozens of entries from around the world, with a shortlist set to be announced later this month and a winner unveiled in July. The design brief notes that “how the bridge looks from afar, as it bestrides the Thames, what it feels like to cross and how it touches land on either shore – and the places that it creates around each landing point – will be critical to its success.”

Thus far, there’s only a gallery of images to look at, without any supporting information on each design, so it’s hard to tell just what we’re looking at in some cases. The City Metric called most of the entries ‘ridiculous,’ pointing out “the one which is definitely not a bridge,” “the one like a nightmarish Escher painting” and “the one that’s a spoon.”

It’s clear enough why the word Hades was invoked to describe the strange violet-and-orange creation pictured above, and it’s unclear how this design would actually function as a bridge. You have to wonder whether some of the entrants are just trolling. But some of the designs are actually quite beautiful, like the one featuring a perforated undulating canopy over a network of paths planted with greenery. However will the judges choose?

Spanning valleys and waterways, bridges perform a basic but essential function: getting us from one side to the other. But what if we expanded on that purpose, inserting everything from opera halls and vertical gardens to entire cities into the design? These 13 bridge concepts stretch beyond the boundaries of traditional design, creating bridges that are multi-purpose or simply astonishingly unusual.

Paik Nam Jun Media Bridge, South Korea

(images via: design boom)

Why should bridges be limited to traffic alone? This incredible concept for the Han River in Seoul imagines the bridge as an essential part of the city itself, filled with activity and attractions including a museum, library, and IT offices. People can even arrive via water taxi. The design, by Planning Korea, has a ‘skin’ covered in solar panels that would also function as a massive canvas for art and videos.

Wind Tunnel Bridge

(image via: treehugger)

Could bridges, which are often positioned over waterways that could act as wind corridors, be used to harvest energy? This concept by Michael Jantzen puts a footbridge to work, equipping it with a series of turbines that turn around pedestrians as they walk through it.

London Bridge as Inhabited Vertical Farm

(image via: inhabitat)

London Bridge has been reincarnated several times already, and someday soon, it will be due for a refresh. Will the 21st-century version be a vision of sustainable urban living, with solar-powered spires covered in vertical farms towering into the air? Chetwood Architects’ proposal would harness solar and wind power, collect rainwater, grow and sell food and even house markets, cafes, restaurants and residences.

Informal Bridge City for Italy

(images via: evolo)

Those afraid of heights would want to steer clear of this city-in-a-bridge concept by Ja Studio, modeled after the Ponte Vecchio in Florence. Created for a contest that aims to identify a creative new use for a decommissioned highway between Salerno and Reggio Calabria in Italy, the proposal places a precarious new urban center onto existing infrastructure to not only provide amazing views but have a small impact upon the ecology of the surrounding landscape.

The Hoover Dam Re-imagined, Nevada & Arizona

(images via: evolo)

At the Hoover Dam, the sheet of water pouring over a face of simple concrete is without a doubt the main attraction. Can you imagine if instead it looked like this, with the water entering a series of containers “to engage directly with visitors?” Designer Yheu-Shen Chua gives the iconic structure a shockingly futuristic makeover that would certainly be controversial if it ever saw the light of day.

LM Harbor Gateway by Steven Holl, Copenhagen

(image via: steven holl)

First prize winner in a competition to design a new harbor entrance to the city of Copenhagen and recipient of the 2010 Progressive Architecture Award, ‘LM Harbor Gateway’ by Steven Holl Architects features two towers, each with its own cable-supported bridge, meeting in the middle in an arrow shape reminiscent of the prow of a ship. The bridge serves as a passageway between two piers and as a public overlook, and the towers contain public facilities like cafes and galleries.

CPH Arch by 3XN, Copenhagen

(image via: e-architect.co.uk)

Another proposal for the Copenhagen harbor, designed by 3XN Architects, takes an entirely different tact. As curvilinear as the Holl design is geometric, the ‘CPH Arch’ – which serves as an office tower – is a single seamless volume teeming with movement and activity.

Skyscraper Bridge Unifies the Korean Peninsula

(image via: evolo)

Peaceful reunification of the two Koreas is the dream of many – but if and when it does happen, environmentalists hope that the 50-mile buffer zone between the two countries will remain as it is. Untouched for 50 years, the Demilitarized Zone (DMZ) is one of the world’s most pristine ecological environments and contains half of the Korean Peninsula’s wildlife. With this in mind, Korean architects Kim Sehyeon, Lee Jung Boram and Choung Yongsu have proposed a skyscraper bridge packed with meeting halls and meditation areas where citizens of both countries could meet.

The UK’s Tallest Bridge by Stephen Spence

(images via: archdaily)

This innovative design, created for the River Wear in Sundlerland, could become the UK’s tallest bridge at over 519 feet. Two curved spires cross in the air, supported by cables, in a striking silhouette that will undoubtedly become a local landmark. The status of the project is unclear, but assuming that funds are available, construction is due to start in 2012 with an anticipated completion date in 2015.

World’s Tallest Bridge in Dubai

(image via: world architecture news)

It seems that Dubai has been on a quest to produce the biggest, most jaw-dropping architectural projects in the world, so it’s no surprise that they’re currently constructing the world’s longest and tallest arch bridge. The design, by NYC firm FXFowle, seems to flout the laws of physics. It may look like the kind of design that’s destined to remain a concept forever, but the Sheikh Rashid bin Saeed Bridge is due for completion in 2012. It’ll have 12 passenger lanes, a dual rail track for Dubai’s Metro Green Line and a man-made island with an opera house, and will carry some 20,000 vehicles per hour.

Solar Wind Concept

(images via: discovery)

Large-scale wind power may necessitate putting turbines in unexpected places – including, perhaps, over rivers and valleys that are often wind corridors. So even if this particular design for a wind turbine bridge – which also has a grid of solar cells embedded on the surface of the road – isn’t entirely realistic, it’s an interesting concept. The designers say the bridge could power as many as 115,000 homes.

Living Bridge Towers Over the Seine River, Paris

(image via: evolo)

Part skyscraper, part bridge, this futuristic building is perched directly on the Seine River in Paris. Designer Nicola Marchi was inspired by the inhabited bridges of Europe’s past, saying “The building is integrated with the Seine, becoming a new landmark and offering the historic center the development of the most varied programmatic elements, including recreational, cultural, residential, and performing spaces. The new bridge for the city is a living one.”

Zaha Hadid’s Sheikh Zayed Bridge, Dubai

(images via: zaha hadid)

Asymmetrical steel arches form a wave-like design, emerging from cantilevered road decks on either side, in this design for Dubai’s Sheikh Zayed Bridge by Zaha Hadid. The architect believes that the bridge, a part of a major four-line highway connecting Abu Dhabi island to the mainland, will become a destination in itself. It’s currently under construction.